Wheatstone Corporation VP-8IP Technical Manual Download Page 212

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VP-8IP / Sep 2013

V P - 8

i P

P R O C E S S M O D E S

MP3/ACC

<48

VP‑8

MP3/AAC<48K Process Mode

The following discussion is unique to the

VP‑8

Audio Processor when it is operating

in its MP3/AAC<48K mode.

There are two menu screens that are unique to the MP3/AAC<48K mode and used

for adjusting how the processor’s final limiting scheme sounds and interfaces with

external transmission equipment. These are the

Limiters and MP3/AAC<48K screens,

the latter being selectable via the MP3/AAC<48K tab only when

VP‑8

is in that codec

processing mode.

Audio processing within the four band AGC takes place in the Sum and Difference

domain, allowing tasteful management of the MP3/AAC<48K mode’s stereo image

without creating codec-teasing artifacts.

LIMITERS MENU - MP3/AAC<48K MODE

Multiband Limiter

The

VP‑8

contains our exclusive, fully adjustable “swish-free” eight band final

limiter algorithm. This limiter is especially effective in controlling program energy

without generating unnatural swishing and “phasey” artifacts that outdated and simplistic

multiband algorithms usually generate.

There are no caveats for using the eight band limiter other than it is inappropriate to

operate the limiters continuously beyond 3dB of limiting when used with codecs. We

generally recommend operating the limiters in a manner that allows them to do three

things: gently increase RMS energy (loudness), shape the instantaneous HF spectrum

to make it more suitable for the MP3/AAC<48K medium, and control longer duration

transients that the preceding four band AGC/compressor intentionally misses in order

to maintain an unrestrained sound quality.

For best musicality we recommend that the multiband limiters not be operated with

extremely short attack and release times. The reasoning behind this is twofold:

1. Extremely short attack times, while affording virtually perfect energy control,

remove so much transient energy that it makes the sound too homogenized and

lifeless.

2. Even though our limiters utilize a delayed release algorithm, extremely short

release times may increase certain coding artifacts. This is because fast release

Limiters Screen in AAC/MP3<48K Mode

Summary of Contents for VP-8IP

Page 1: ...TECHNICAL MANUAL Digital Multimode Audio Processor VP 8IP 600 Industrial Drive New Bern North Carolina USA 28562 ...

Page 2: ...udio Processor Technical Manual VP8IP GUI version 4 X X exe 2013 Wheatstone Corporation VP 8 IP Sep 2013 600 Industrial Drive New Bern North Carolina 28562 tel 252 638 7000 fax 252 637 1285 Ultra High Resolution Processing ORSIS ...

Page 3: ...installed and used in accordance with the instruction manual may cause harmful interference to radio communications Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his own expense This is a Class A product In a domestic environment this product may cause radio interference in which case...

Page 4: ...ed in the System pane You will see something like this Now select the Peripheral Devices tab Click the Add button to bring up the Add Peripheral Device dialog Type in a convenient Name and insert the IP Address of the device being added Leave the TCP Port at the default setting of 60021 From the Host BLADE drop down select the BLADE that you want to associate the Peripheral device with Click Ok Th...

Page 5: ...uts 1 8 Analog In 1 8 AES In 1 8 SCA In 1 9 Audio Outputs 1 9 Analog Out 1 9 AES baseband192 Out 1 9 TX Out 1 9 Headphones 1 9 Network Connection 1 10 Ethernet RJ 45 1 10 Typical Ethernet Cable 1 10 Typical Crossover Cable 1 10 General Purpose Interface GPI GPO 1 11 GPI 1 11 Example Schematic of General Purpose Inputs 1 12 User Presets 1 13 GPO 1 13 Analog XLR Connections Pinouts Drawing 1 15 Digi...

Page 6: ... ACCESS 2 17 Adding VP 8IP to a WheatNet IP System 2 18 Achieving the Desired Sound 2 20 First a Few Words About Our Factory Presets 2 20 What Sound Are You Trying to Achieve 2 20 About Bass 2 20 Is There a Caveat 2 20 What Is Your Short Term Goal 2 21 How Do I Make It Louder 2 21 What Is Your Long Term Goal 2 21 Clean and Loud 2 22 Can I Generate That Sixties Compression Sound 2 22 VP 8IP Front P...

Page 7: ...4 Network Configuration 4 4 Getting Started 4 4 Connecting the VP 8ip and the Pro GUI 4 5 Using a LAN Connection 4 5 Configuring the VP 8ip IP Address 4 5 Adding Devices 4 7 Connecting Directly Without a LAN 4 9 PC System Requirements 4 9 Wireless Connection 4 9 The Really Remote Connection 4 10 VPN 4 10 The VP 8ip and Internet Security Concerns 4 10 About DHCP and the VP 8ip 4 10 About Ports and ...

Page 8: ...ns 4 26 Gating and AGC Backoff 4 27 Gating Threshold 4 27 Gating Delay 4 27 Gain Freeze 4 27 Slow Recovery 4 27 InterBand Coupling 4 28 AGC Backoff 4 28 Crossover Frequencies 4 29 Selecting Crossover Frequencies 4 29 AGC Compressor Gain Reduction 4 30 System Menu 4 31 Input Output Settings Change With Presets 4 31 Metering Data Over TCP IP 4 32 Headphone Source 4 33 Headphone Control 4 33 Process ...

Page 9: ... 9 Processing Common to All Modes 5 10 VP 8ip FM Process Mode 5 11 Limiters Menu 5 11 Multiband Limiter 5 11 Multiband Enable 5 12 Multiband Drive 5 12 Multiband Knee 5 12 Bass Tools 5 13 Drive 5 14 Style 5 14 Frequency 5 14 Output 5 15 Pre Emphasis Selection 5 15 Type 5 15 Location 5 15 Multiband Limiter Adjustments 5 16 Threshold Screen 5 16 Attack Time Screen 5 17 Release Time Screen 5 18 Final...

Page 10: ... Analog Output 5 27 TX 1 5 28 TX 2 5 28 Pilot Only 5 28 Analog Output and MPX Modes 5 28 VP 8ip AM Process Mode 5 30 Limiters Menu 5 31 Multiband Limiter 5 31 Multiband Enable 5 31 Multiband Drive 5 31 Multiband Knee 5 32 Bass Tools 5 33 Drive 5 33 Style 5 33 Frequency 5 34 Output 5 34 Pre Emphasis Selection 5 34 Type 5 34 Location 5 34 Multiband Limiter Adjustments 5 35 Threshold Screen 5 35 Atta...

Page 11: ...imiter 5 48 Multiband Enable 5 49 Multiband Drive 5 49 Multiband Knee 5 49 Bass Tools 5 50 Drive 5 51 Style 5 51 Frequency 5 51 Output 5 52 Multiband Limiter Adjustments 5 53 Threshold Screen 5 53 Attack Time Screen 5 54 Release Time Screen 5 55 Final Equalization Screen 5 56 FM HD Menu 5 57 FM HD Look Ahead Limiter 5 57 FM HD Look Ahead Limiter Controls 5 58 Look ahead Limiter Enable 5 58 Left Ri...

Page 12: ... 71 L R Linked 5 71 Lim Limiter Drive 5 71 Attack 5 71 Release 5 72 Delayed Release 5 72 Phase Reverse 5 73 Left Right Reverse 5 73 Analog 5 73 Digital Output 5 73 VP 8ip MP3 AAC 48K Process Mode 5 74 Limiters Menu 5 74 Multiband Limiter 5 74 Multiband Enable 5 75 Multiband Drive 5 75 Multiband Knee 5 75 Bass Tools 5 76 Drive 5 77 Style 5 77 Frequency 5 77 Output 5 78 Multiband Limiter Adjustments...

Page 13: ...Time Screen 5 95 Release Time Screen 5 96 Final Equalization Screen 5 97 MP3 AAC 48K Menu 5 98 Multiband Drive 5 98 The Vorsis Spectral Energy Gate 5 98 Adaptive Bandwidth Controller Controls 5 99 Codec Sample Rate 5 99 Low Pass Filter 5 99 Codec Bitrate 5 100 Mask Thresh and Mask Recovery 5 100 Achieving the Proper Settings 5 100 MP3 AAC 48K Look Ahead Limiter 5 102 MP3 AAC 48K Look Ahead Limiter...

Page 14: ... 1 8 SCA In 1 9 Audio Outputs 1 9 Analog Out 1 9 AES baseband192 Out 1 9 TX Out 1 9 Headphones 1 9 Network Connection 1 10 Ethernet RJ 45 1 10 Typical Ethernet Cable 1 10 Typical Crossover Cable 1 10 General Purpose Interface GPI GPO 1 11 GPI 1 11 Example Schematic of General Purpose Inputs 1 12 User Presets 1 13 GPO 1 13 Analog XLR Connections Pinouts Drawing 1 15 Digital XLR Connections Pinouts ...

Page 15: ...ssing experts In that version there are no hidden controls and no secret back door to hide things from the end user Every control is available and labeled for exactly what they do so prior experience with audio processing adjustment is definitely recommended Obtaining the full control Pro GUI is simple and it s free Simply register for it at our website http wheatstone processing com Regardless of...

Page 16: ...ver rely on offshore or contract manufacturing As audio professionals and audio perfectionists we believe that our cus tomers should have not only the right but also the power to shape their OWN sound onewithacompletelyuniquesonicsignaturethat stheirs nottheonecreated by a processor manufacturer To get there it required our team to take a completely fresh approach to audio processor design To achi...

Page 17: ...r band linear phase crossover with adjustable crossover points Exclusive Wheatstone Multiband Dynamics Processing Precision eight band multiband limiter Specialized codec preconditioning tailored for each of the four CODEC modes Advanced Distortion Masked Clipper for absolute FM and AM peak control Reference grade stereo encoder available in FM mode Adjustable positive asymmetry LF tilt correction...

Page 18: ... the unit If only two screws are being used they must be used in the bottom holes in order to provide proper support The VP 8ip does not have top or bottom cover vent holes Latent heat is vented out of the enclosure by natural convection through slots in the top of the rear panel Cooler air is drawn into the unit through vertical slots positioned lower in the side panels There is no fan inside the...

Page 19: ...o 70 ohms and represents a large impedance mismatch from the nominal 110 ohms required in the AES3 standard Such mismatch will result in signal reflections causing bit errors at the AES3 receiver The higher capacitance of generic analog cables also slows down the rise time of the digital data signals impairing the ability of the AES3 receiver to accurately detect digital signal transitions This ma...

Page 20: ...to remove redundant audio information and mask that removal Therefore codec operation may be much more obvious potentially more so than what might occur with the processing located after the codec where the masked artifacts are simply unmasked by the increased gain due to processing Energizing Assuming the VP 8ip Digital Audio Processor is correctly rackmounted you may now energize it There is no ...

Page 21: ...ft right audio DigitalAES3compliantleft rightaudiowithsampleratesbetween32kHzand96kHz Optional WheatNet IP via 100BaseT Ethernet connection to a WheatNet IP audio network Input audio can be applied to all inputs simultaneously Automatic audio failover from analog to digital or vice versa is supported Automatic failover from AES3 or WheatNet IP to analog is instantaneous and based on invalid or mis...

Page 22: ... XLR LT SH LINE LT OUT SH Pin 2 XLR LT HI LINE LT OUT HI Pin 3 XLR LT LO LINE LT OUT LO Pin 1 XLR RT SH LINE RT OUT SH Pin 2 XLR RT HI LINE RT OUT HI Pin 3 XLR RT LO LINE RT OUT LO AES baseband192 Out XLR M Pin 1 XLR SH AES BASEBAND192 OUT SH Pin 2 XLR HI AES BASEBAND192 OUT HI Pin 3 XLR LO AES BASEBAND192 OUT LO TX Out BNC Pin 1 BNC 1 HI TX 1 OUT HI Pin 2 BNC 1 SH TX 1 OUT SH Pin 1 BNC 2 HI TX 2 ...

Page 23: ...you are connecting directly between the computer and the VP 8ip with no network in between it is normal to use a crossover cable Ethernet RJ 45 Pin 1 TXD Pin 2 TXD Pin 3 RXD Pin 4 N C Pin 5 N C Pin 6 RXD Pin 7 N C Pin 8 N C Typical Ethernet Cable Typical Cr ossover Cabl e 1 2 3 4 TXD TXD RXD RXD PIN 1 2 3 4 PIN RJ 45 Plug RJ 45 Plug White Orange 5 6 7 8 N C N C 5 6 7 8 Orange White Green Blue Whit...

Page 24: ... Pin 7 GPI 3 IN Pin 3 GPI 4 IN Pin 8 GPI 5 IN Pin 4 GPI 6 IN Pin 9 GPI 7 IN Pin 5 GPI 8 IN The GPI input circuits are optoisolated by devices with a 1 500VAC isolation rating Each of the GPI inputs is current limited by a 475 ohm resistance The LED device inside the optoisolators is rated at a maximum forward current of 50mA with a normal operating current of 5mA therefore it is necessary to deter...

Page 25: ...page 1 12 VP 8IP Sep 2013 G E N E R A L I N F O R M A T I O N Example Schematic of General Purpose Inputs ...

Page 26: ...as the Stereo Pilot turned off Mono Preset Preset storage is typically as follows Presets 1 8 are user presets that can be quickly selected from the GPI con nector Factory presets are installed starting at Preset 9 with Preset 9 being a bypass preset The factory presets cannot be written over or deleted User presets other than the GPI selectable presets 1 8 are stored above the highest factory pre...

Page 27: ...O R M A T I O N The pin assignment for the rear panel DB 9 GPO connector is as follows Pin 1 N C Pin 2 GPO 1 Return Pin 6 GPO 1 Source Pin 3 GPO 2 Return Pin 7 GPO 2 Source Pin 4 GPO 3 Return Pin 8 GPO 3 Source Pin 5 GPO 4 Return Pin 9 GPO 4 Source ...

Page 28: ...LO XLR LT F 2 1 3 PIN 1 XLR RT SH LINE RT IN SH PIN 2 XLR RT HI LINE RT IN HI PIN 3 XLR RT LO LINE RT IN LO XLR RT F Analog Out XLR M 1 2 3 PIN 1 XLR LT SH LINE LT OUT SH PIN 2 XLR LT HI LINE LT OUT HI PIN 3 XLR LT LO LINE LT OUT LO XLR LT M PIN 1 XLR RT SH LINE RT OUT SH PIN 2 XLR RT HI LINE RT OUT HI PIN 3 XLR RT LO LINE RT OUT LO XLR RT M 1 2 3 Analog XLR Connections ...

Page 29: ...AES In XLR F 2 1 3 PIN 1 XLR SH AES IN SH PIN 2 XLR HI AES IN HI PIN 3 XLR LO AES IN LO XLR F Digital XLR Connections 1 2 3 PIN 1 XLR SH AES BASEBAND192 OUT SH PIN 2 XLR HI AES BASEBAND192 OUT HI PIN 3 XLR LO AES BASEBAND192 OUT LO XLR M AES Out baseband192 XLR M ...

Page 30: ...I SCA 1 IN HI CENTER PIN BNC SCA PIN 2 BNC 1 SH SCA 1 IN SH SHELL PIN 1 BNC 2 HI SCA 2 IN HI CENTER PIN PIN 2 BNC 2 SH SCA 2 IN SH SHELL 1 2 PIN 1 BNC 1 HI TX 1 OUT HI CENTER PIN BNC TX PIN 2 BNC 1 SH TX 1 OUT SH SHELL PIN 1 BNC 2 HI TX 2 OUT HI CENTER PIN PIN 2 BNC 2 SH TX 2 OUT SH SHELL 1 2 ...

Page 31: ...8 TXD TXD RXD RXD N C N C N C N C General Purpose Interface DB 9 GPI 7 IN GPI 5 IN GPI 1 IN GPI 8 IN GPI 6 IN GPI 4 IN GPI 2 IN GPI COM GPI 3 IN GPI DB 9 GPO 4 OUT SOURCE GPO 3 OUT SOURCE GPO 1 OUT SOURCE GPO 4 OUT RETURN GPO 3 OUT RETURN GPO 2 OUT RETURN GPO 1 OUT RETURN N C GPO 2 OUT SOURCE GPO DB 9 ...

Page 32: ...2 10 PRESETS 2 10 MODE S 2 11 INPUT 2 11 OUTPUT 2 13 FM Mode 2 13 AM Mode 2 14 FM HD Mode 2 15 AM HD Mode 2 15 MP3 AAC 48kHz Mode 2 16 MP3 AAC 48kHz Mode 2 16 NETWORK 2 17 VERSION 2 17 ACCESS 2 17 Adding VP 8IP to a WheatNet IP System 2 18 Achieving the Desired Sound 2 20 First a Few Words About Our Factory Presets 2 20 What Sound Are You Trying to Achieve 2 20 About Bass 2 20 Is There a Caveat 2 ...

Page 33: ...ause I don t have time to read the whole manual Please check out the various chapters of this manual if you need some additional information If for some reason you find that you re really stuck you can always call our friendly technical support folks at 252 638 7000 Please inspect the contents of the package to ensure that the following items are present Wheatstone VP 8ip Unit Quantity 1 VP 8ip Gu...

Page 34: ...e VP 8ip front panel Input and Output meters 8 While still in the Calibrate Input Output menu and observing the Input meters within the Guru or on the front panel adjust the Input Gain control AES or Analog as required until the input meters are peaking at no more than 12dBFS with normal program levels being applied 9 If using the Analog outputs pre emphasized navigate to the Calibrate Input Outpu...

Page 35: ...d and play with Presets can easily be installed into your VP 8ip using the Preset management features within the remote GUI The following pages contain additional startup information Please excuse us if there is some repetition of information we know that some of you will be jumping aroundinthemanualratherthanreadingitsequentially Afterall we reengineerstoo Introducing the VP 8ip VP 8ip is a colle...

Page 36: ... Scroll again to EDIT and press You will see the IP address with the first octet 192 assuming the factory default address flashing For each octet dial up a new number if necessary then press to accept After doing the IP address the subnet mask will be presented for possible editing followed by the gateway Once the VP 8ip IP address is set proceed to the section below titled Telling the GUI How to ...

Page 37: ...rogrammed default IPaddress subnet and gateway settings and the remote GUI so that they agree on the networking parameters Before starting the configuration procedure please locate and carefully make a note of the VP 8ip s 12 digit MACAddress which is printed on a label either on the top cover or the rear panel This address will be in the format 00 50 C2 xx xx where xx xx xx are the digits unique ...

Page 38: ...o use the default values from the form Once this is done click the Start button at the bottom of the IP address configuration box A message similar to the one below should appear Click OK then remove power to the VP 8ip for a few seconds and then reapply it As the VP 8ip is booting up the Requests number in the IP Address window should increment to something other than zero please see the bottom o...

Page 39: ...ontheOnline OfflinebuttonjusttotheleftoftheOnlineStatusindicator In the Status window you may see the message Trying as the GUI is handshaking with the VP 8ip Once the handshake is complete and communication protocols are locked in the Status message should revert to Online If for some reason the GUI cannot connect with the VP 8ip the Trying status message will remain and will occasionally blink a...

Page 40: ...ta back to the GUI from the VP 8ip We prefer UDP because of its low overhead and because we don t really mind if a meter data packet is dropped occasionally They are updated so fast that missed meter packets are inconsequential to the operation of the unit What this means is that network traffic on TCP port 55890 and the UDP port range 60000 60010 must be allowed on the portion of the network betw...

Page 41: ...he OUTPUT menu item radically changes as the VP 8ip mode is changed due to large differences in the controls present in the various operating modes In the following pages the front panel navigation will be examined in more detail NOTE Please use the detail shown in the following sections to determine where the appropriate setup controls will be for your particular VP 8ip operating mode and install...

Page 42: ... other disturbing audio discontinuities from appearing at the VP 8ip outputs while the new mode s processing algorithms are being loaded into the DSPs and started up INPUT The INPUT menu item allows the appropriate audio input type to be selected whether Analog or Digital AES or WheatNet IP and also allows independent input gain adjustments to be made for each of the two input types INPUT SOURCE A...

Page 43: ...LADE used may even be the mul tiband eight processorAura8ip Processing BLADE whose physical inputs and outputs half analog half digital may even be used as a substitute for VP 8ip s physical I O Now it s time to open up WheatNet IP Navigator to gain access to VP 8ip s WNIP associated input and output signals Once the WheatNet IP Navigator software is open and you are logged into the system we must...

Page 44: ...dB L R DE EMPH ANALOG OUT PILOT PILOT INJ SCA 1 SCA 1 LEVEL dB SCA 2 SCA 2 LEVEL dB DIG OUT AES3 DIGITAL LEVEL dBFS DE EMPH OUT BASEBAND192 IN OUTPUT The output menu tree is tailored to the current VP 8ip operating mode with the most complex being the FM and AM modes due to their specialized processing requirements The output menu tree for each of the six modes follows along with the corresponding...

Page 45: ...T OUTPUT PRE EMPH FLAT ANALOG INPUT AM B WIDTH FULL NRSC DIGITAL INPUT 4 5kHz PREDELAY 5 0kHz ANALOG OUT 5 5kHz 6K CCIR 6 5kHz 7 5kHz 10kHz NRSC OUT MODE MONO POSMOD 100 150 STEREO ANALOG 1 LEVEL dB M S PHASE ANALOG 2 LEVEL dB PHASE DIG OUT DIGITAL LEVEL dB DE EMPH OUT IN ...

Page 46: ...INPUT OUTPUT ANALOG LEVEL dB ANALOG INPUT FM HD DIG OUT DIGITAL LEVEL dB DIGITAL INPUT PHASE PREDELAY L R SWAP ANALOG OUT AM HD Mode HEADPHONE SOURCE INPUT OUTPUT ANALOG LEVEL dB ANALOG INPUT AM HD DIG OUT DIGITAL LEVEL dB DIGITAL INPUT PHASE PREDELAY L R SWAP ANALOG OUT ...

Page 47: ...E INPUT OUTPUT ANALOG LEVEL dB ANALOG INPUT 48K DIG OUT DIGITAL LEVEL dB DIGITAL INPUT PHASE PREDELAY L R SWAP ANALOG OUT MP3 AAC 48kHz Mode HEADPHONE SOURCE INPUT OUTPUT ANALOG LEVEL dB ANALOG INPUT 48K DIG OUT DIGITAL LEVEL dB DIGITAL INPUT PHASE PREDELAY L R SWAP ANALOG OUT ...

Page 48: ...plays the currently loaded versions of operating system FPGAimage and DSP code noting that these are displayed values only and cannot be changed without actually changing the version s that the VP 8ip is running i e updating it to a new version ACCESS LOCK ACCESS UNLOCK EDIT CHANGE N Y OLD NEW The Access item allows the front panel security features of the VP 8ip to be customized Afrontpanelpasswo...

Page 49: ... system Here we will add the new VP 8ip s name its hardware IP address and tell the system what BLADE will be its host while any BLADE can be its host all third party devices must have a host We do not have to modify the TCP Port setting so we can leave it set to 60021 Once input to the dialog is finished click on the Ok button and it will close Next we ll open Navigator s System Crosspoint window...

Page 50: ...g may be done through the many other methods available within the WheatNet IP system for routing signals and changing the routes of both audio and logic signals More information on configuring and using WheatNet IP Navigator and the other features and capabilities of the WheatNet IP system may be found in the WheatNet IP System product documentation Assistance in configuring VP 8ip for WheatNet IP...

Page 51: ... of and what a typical listener might find appealing Please feel free to experiment with the presets as each one has a unique sound but don t fall into the trap of thinking that for instance the Country presets are only good for Country music formats The preset that sounds best with your program format is the one to use either as is or as the foundation sound on which to add your personalized touc...

Page 52: ...he four band AGC by operating it with faster attack and release times Increase the Drive to the eight band limiters Carefullyusesomeequalizationintheparametricsectiontogentlyboost frequencies that the ear is most sensitive to 1kHz to 4 kHz Drive the limiter section harder to further increase the amount of RMS energy being generated by the processing Operate the eight band section with faster attac...

Page 53: ...configured for post AGC Compressor operation with a center frequency of around 1 2kHz a bandwidth of about 1 5 octaves and a cut of no more than about 1 to 2 dB The above combination will somewhat relax the sound because the AGC sections are operating slower slightly lowering their average output levels and also because of the slightly reduced levels in the ear s most sensitive region due to the m...

Page 54: ...educed in several ways Reduce the amount of reverb Operate the AGC Backoff control at slightly less negative numbers Reduce the overall drive to the AGC Compressor section Raise the Gate Threshold to less negative numbers and decrease the Gate Delay time to something under 100mSec You can use these methods alone or in combination to control reverb tails Alternately if your station s sound demands ...

Page 55: ...page 2 24 VP 8IP Sep 2013 VP 8ip Front Panel Menu ORSIS Ultra High Resolution Processing ...

Page 56: ...RIX AGC 4 BAND CROSSOVER 8 BAND LIMITER LOOKAHEAD LIMITER AGC MIXER 8 BAND LIMITER MAIN AM CLIPPER LOOKAHEAD LIMITER MATH 4 BAND PARAMETRIC EQUALIZER OVERSHOOT CALCULATOR 8 BAND LIMITER FM HD CODEC CONDITIONING LOOKAHEAD LIMITER MATH 4 BAND PARAMETRIC EQUALIZER OVERSHOOT CALCULATOR 8 BAND LIMITER AM HD CODEC CONDITIONING LOOKAHEAD LIMITER MATH 4 BAND PARAMETRIC EQUALIZER OVERSHOOT CALCULATOR 8 BAN...

Page 57: ...ix Controls Why Not Just One 3 9 How Do the Tweakers Work 3 9 What Causes a Guru Control To Stop Before Reaching 0 or 10 3 9 The Six Tweakers 3 11 AGC Depth 3 11 Compression 3 11 Density 3 11 Loudness 3 12 HF EQ 3 12 LF EQ 3 12 Guru Caveats 3 13 Understanding the Difference Between Factory Legacy and Guru Presets 3 13 The Other Two Pages of Guru 3 14 Additional Notes On VP 8ip Network to GUI Conne...

Page 58: ...he sound of our Factory presets without hundreds of tweakable parameters staring back at them Guru has only three basic pages hosting controls that an end user might need for installing the processor and adjusting its sound The first page of Guru is called Adjust Sound and is solely dedicated to making refinements to our Factory preset s default sound The second page of Guru is the Calibrate Input...

Page 59: ...mode configuring the GUI to communicate with the host audio processor and programming the Scheduler Note that for user convenience we ve repeated the appearance of some of the controls across various pages noting that the Input Output and processing related metering are always visible on all three pages Adjust Sound Calibrate In Out Configuration ...

Page 60: ...t IP address of 192 168 1 198 Please follow the steps below noting that if the VP 8ip s Factory default IP address of 192 168 1 198 will work on your network you should skip to step 1 on page 3 5 1 Before starting the configuration procedure please locate and carefully make a note of the processor s 12 digit MAC Address lo cated on a label either on the top cover or the rear panel This address wil...

Page 61: ...UI so that it can talk to the VP 8ip This is done by adding to the list of devices that the VP 8ip s GUI knows about To do this 2 Right click on the control area of the Guru and select Devices The Devices window shown on the right will pop up 3 Next click the Add button and the Edit Device dialog box will appear this box is used for adding new devices or modifying the configura tion of existing on...

Page 62: ...address must be between the addresses 192 168 1 1 and 192 168 1 254 noting that the VP 8ip and GUI PC cannot share the same IP address NOTE TCP port 55890 must be open in any switch or router configuration in order to permit traffic between VP 8ip and GUI Setting the Input Audio Levels Connect the Analog or Digital audio inputs as appropriate for your installation Start up the VP 8ip Guru applicat...

Page 63: ...ight outputs are also transmitting composite stereo not balanced Left Right audio as you might expect If you have an exciter that provides a balanced composite input most do even though the composite input is a BNC connector the best signal to noise performance will be obtained by using the VP 8ip s balanced outputs Give us a call if you d like to interface to your exciter using this method and we...

Page 64: ...all Resist the temptation to try to fix the processing for the one song that sounds bad Instead try to determine why that cut sounds bad If it s the source material fix it If not then you can work on the processing Too many get these processes reversed and spend a lot of time tuning and tuning and still get nowhere The tweaking controls in Guru are located on the Adjust Sound tab of the GUI On thi...

Page 65: ...oint positions which is 5 for the texture tweakers and 0 for the EQ controls Each tweaker then allows adjustments up and down from a Factory preset s starting point We vemadetheadjustmentrangeofeachtweakerprovideplentyofrangearound our Factory preset values and as we ve previously seen with just six tweakers millions of possible sound textures can be created As always you can safely get right back...

Page 66: ...reach 8 before Var 7 maxes out Whenever an internal value reaches its limit the Guru control is prevented from going any further in that direction Now let s look at the opposite scenario where the Guru tweaker is being pulled down and Var 3 which is already nearer its lower limit will reach that limit before any others Guru s tweaker might only be able to get down to a setting of 3 before being pr...

Page 67: ... audible it is Pushing the tweaker up to higher numbers causes an increase in the audibility of compression This effect may be desirable in some formats in order to create a certain level of excitement on the air Likewise reducing the setting of the Compression tweaker reduces the audibility of compression Those seeking that old 60 s retro sound will find the Compression tweaker quite useful Tech ...

Page 68: ...o HF EQ This control modifies the balance of high frequencies to mids and lows The control assumes a setting of 5 when a factory pre set is taken and the more the control is turned above five the brighter the audio will sound Conversely the more the control is turned towards zero the less bright the audio will sound The control will reset back to 5 if the factory preset is retaken LF EQ This contr...

Page 69: ... is not allowed to be modified using Guru 3 Pro GUI can customize presets created by Guru although the reverse is not true Why Pro GUI has full control of all parameters regardless of how where and by whom they were created Guru does not have this capability 4 Guru is not permitted to recall a factory preset modify it save it recall it and then modify it again Why Such an exercise would likely not...

Page 70: ...f Guru come in To find all the controls in Guru simply press one of the three navigation buttons at the top of the GUI s navigation bar Up to now we ve been discussing the Adjust Sound page as that s the one that most customers will want to play with first But there are two other pages of Guru that need some explanation too the ones that are reached using the Calibrate Input Output and Configurati...

Page 71: ...GeneratorcontrolsthereareothersforselectingtheAnalogorDigital input adjusting the gains for the Analog and Digital inputs setting the High Pass Filter cutoff frequency and selecting the audio source for the headphone output Note that for convenience the headphone volume control appears on all pages of Guru and the headphone source selector is present on both the Calibrate Input Output and Configur...

Page 72: ...gs allows the VP 8ip to be switched to one of its six specialized operating modes This page also hosts the links to the Preset Scheduler and Device configuration dialogs Device configuration was covered earlier in this chapter Preset or Event Scheduling is covered in the next chapter which describes the Pro version of the GUI VP 8ip Guru Configuration Page ...

Page 73: ...to be able to use TCP port 55890 and UDP ports in the range of 60000 to 60010 on the portion of the network connecting the VP 8ip and the host PC running Guru The most common problem we see is UDP packets being blocked on the host network When this happens Guru won t be able to receive metering data from the VP 8ip In this case you ll notice that you re connected GUI status is Online and will even...

Page 74: ... Support Our technical support department is available weekdays during the hours of 8 30am to 5 30pm U S East coast time Our telephone number is 252 638 7000 Our website can be found at http wheatstone processing com and provides a wealth of information about our products User manuals specialized presets the very latest software and a plethora of application notes in PDF format are available for d...

Page 75: ...Wireless Connection 4 9 The Really Remote Connection 4 10 VPN 4 10 The VP 8ip and Internet Security Concerns 4 10 About DHCP and the VP 8ip 4 10 About Ports and the VP 8ip 4 11 Using the VP 8ip Pro GUI 4 12 Dynamic Displays Region 4 13 Frequency Domain Graph 4 13 VP 8ip Graphical Interface Operation 4 14 First a short tutorial 4 15 Bargraph Metering 4 16 Selectable Meter 4 16 AES And TX Output Met...

Page 76: ... AGC Enable Comp Enable Buttons 4 26 Gating and AGC Backoff 4 27 Gating Threshold 4 27 Gating Delay 4 27 Gain Freeze 4 27 Slow Recovery 4 27 InterBand Coupling 4 28 AGC Backoff 4 28 Crossover Frequencies 4 29 Selecting Crossover Frequencies 4 29 AGC Compressor Gain Reduction 4 30 System Menu 4 31 Input Output Settings Change With Presets 4 31 Metering Data Over TCP IP 4 32 Headphone Source 4 33 He...

Page 77: ...ave 4 40 Library 4 41 Devices 4 41 Quick Save QSave 4 42 Title Bar Region 4 43 Status 4 43 Devices 4 43 Presets 4 44 Notes on Online and Offline Working 4 45 Accessing Menu Options 4 46 File Menu Items 4 46 Hardware Menu Items 4 46 VP 8ip Hardware Update 4 47 Presets Menu Items 4 49 ...

Page 78: ...to any folder desired on the host computer Use the Browse opportunity when presented during the installation process to point the installer to put the Pro GUI files in any folder desired If a custom program location is not entered the resulting files will be installed under the default location for all Windows based Pro GUI s Program Files Vorsis application folder name where in this instance the ...

Page 79: ...P 8ip IP Address Once the Pro GUI has been installed you must configure it and the VP 8ip so that they can communicate with each other This requires configuration for both the VP 8ip and the remote Pro GUI so that they agree on the networking parameters Before starting the configuration procedure please locate and carefully make a note of the VP 8ip s 12 digit MAC Address which is located on a lab...

Page 80: ...on the network Please consult your friendly IT manager if necessary Next enter a pet name for your VP 8ip like WABC VP8ip 2 etc Then enter the IP address that you wish the VP 8ip to have noting that this address must be unique if the VP 8ip will be communicating over your network Next enter the desired Subnet Mask and Gateway IP addresses In some cases but not all it is sufficient to use the defau...

Page 81: ...adding devices to the list of VP 8ip s that the Pro GUI knows about To do this locate and click on the Devices button that is located along the right side of the Pro GUI When this is done the following window will pop up Next click the Add button and the Edit Device dialog box will appear This box is used for adding new devices or modifying the configuration of existing ones Devices Button ...

Page 82: ...s step tells the Pro GUI specifically which VP 8ip you want to connect to Next click on the Online Offline button just to the left of the Online Status indicator In the Status window you may see the message Trying as the Pro GUI is handshaking withtheVP 8ip Oncethehandshakeiscompleteandcommunicationprotocolsarelocked in the Status message should revert to Online If for some reason the Pro GUI cann...

Page 83: ...speed running at least Windows 2000 or Windows XP and the screen resolution should be at least 1024 x 768 pixels in order to get the full benefit of the high resolution graphics utilized There should be at least 15MB of free space on the hard drive for the Pro GUI software and presets and the PC s LAN interface NIC should be 100baseT 100MHz capable for best performance Wireless Connection Many use...

Page 84: ...y are physically located VPN tunnels can be configured both with and without data encryption Setting up a VPN is not difficult but certainly beyond the scope of this manual Although we have not specifically tested the VP 8ip with VPN connections there is no technical reason why it would not work The VP 8ip and Internet Security Concerns The VP 8ip does not act as a web device or web server nor doe...

Page 85: ...one GUI to run at a time on any given PC the GUI will attempt to open port UDP 60000 If that port cannot be opened the GUI will then try port 60001 then 60002 etc up to 60010 Whichever port successfully opens first that port number will be sent to the VP 8ip and the VP 8ip will begin to stream meter data over that UDP port back to the GUI Note if there are two or more GUIs attached to the VP 8ip t...

Page 86: ...ro GUI may be minimized on the desktop taken off the screen and or closed by way of the familiar controls at the extreme top right Descriptions of the features and functions of the Pro GUI will follow different discrete regions of the screen it will begin with the most eye catching region the Dynamic Displays and then we ll explain the Control Area above it followed by the Side Bar buttons and las...

Page 87: ...nge remains at 30dB with gradations every 3dB This display appears when Audio is checked and Gain Reduction and Controls are unchecked Anumberofreal timedynamicallyvaryingspectraandotherfrequency response versus time data may be observed simultaneously A row of large buttons under the graph determines what data is displayed and there are also buttons to enable disable the display of equalizer freq...

Page 88: ...licking a dot to highlight it to turn it orange and then dragging it with the mouse various operating parameters for each band can be customized There are other ways to set parameters too In fact all of the controls on the graphical screen work the same way regardless of which processing section owns them Parameters within each of the processing sections can be accessed by clicking on the associat...

Page 89: ...graphical area and selecting Group All Adjusters removes all highlighted dots turning all orange dots back to blue Conversely right clicking and selecting UnGroupAllAdjusters turns all remaining blue points orange mean ing they can now each be individually adjusted The Flatten function although next in the list is best explained last Okay highlightasingledotagain anydotwilldo Thenrightclickthe gra...

Page 90: ... Adjacent to the graph and to the left and right and sharing a 30dB vertical range 0 30dB of gain reduction 30dB signal level meter range are a group of vertical bargraph level indicators for signal levels and gain reduction The level meters are peak over average types with peaks riding as a lone dot over a solid bar graphed average An Over indication is at the top but slightly distanced from the ...

Page 91: ...graphical display above it Input Pressing this button enables a Fast Fourier Transform FFT based real time spectral analysis of the selected Left Right input signal An FFT is a mathematical filtering process which calculates the spectral content of a time domain signal The FFT1 is widely used in test equipment in the audio industry because of its extremely precise measurement capability Thanks to ...

Page 92: ...rsity delay Gain Reduction When this box is checked the graphical display includes information related to the amount of gain reduction occurring in theAGC and compressor The Blue line indicates long term AGC activity while the Yellow line indicates the shorter term compression Controls When this box is checked and if there are controls available for the page being viewed they will be shown as blue...

Page 93: ... resolution of the control variation can be increased made finer by holding down the keyboard s Ctrl key while adjusting the control as above or In most cases you can double click on the text that indicates the setting value for example the window that reads X XdB under the Line Gain knob on the Input Section and a box will pop up where you can enter an exact value and click OK From left to right ...

Page 94: ...urrently selected input is shown by a red checkmark Input Signal Presence Below the source selection check boxes are a pair of signal presence indicators The Analog indicator lights if there is a signal present at the analog input that exceeds the threshold of 48dBFS The AES indicator lights if there is a valid AES signal present at the digital input that is above 48dBFS Automatic Input Failover I...

Page 95: ...it is usually peakier in one polarity than the other The algorithm fixes these asymmetrical peaks by phase shifting the signal harmonics relative to their fundamentals This reduces the peak to average ratio and enables an increase in apparent loudness with minimal audible detriment Processing the audio for a symmetrical medium like FM is greatly simplified if the waveforms are symmetrical Ordinari...

Page 96: ... Freq slider and one for the Diff Freq slider are visible Checking a box activates a high pass filter on that channel sum or difference L R or L R Separate frequency sliders are available for adjusting the high pass filter corner frequency for each signal path The mono L R and stereo L R signal paths may have different high pass filter cutoff frequencies Why the Sum and Difference Option In most p...

Page 97: ... each position is different WhentheparametricequalizerisusedaheadofthemultibandAGCtheequalization curves pre load the AGC drive to make it operate in a frequency conscious way Be aware however that EQ changes made to the audio even dramatic changes might be reduced when the audio goes through the multiband compressor especially when operating with ratios greater than about 4 1 The controls of the ...

Page 98: ... the curve s height above or below the 0dB reference line up or down move Clicking on the little tent shaped symbol underneath and holding the left mouse button down and sliding the mouse left or right allows you to change the bandwidth or Q of the equalizer section Right clicking on the graphic opens a window for manual selection of which curve is to be manipulated with the mouse EQ Master Enable...

Page 99: ...e The AGC Drive control adjusts the amount of signal into the AGC Compressor primarily determining the amount of compression that can be achieved Driving harder higher numbers results in a more consistent on air sound with an increased capability to pull up low passages in program material Less drive creates a more gentle on air sound and has less capability to bring up low passages The Drive cont...

Page 100: ...ons determine the presence of theAGC section and the Compressor section in the output AGC Enable When illuminated by clicking on it indicates that the output of the AGC section is in the audio path Comp Enable When illuminated by clicking on it indicates that the output of the Compressor section is in the audio path Compressor Out AGC Out When both AGC and Compressor are switched off signal is bei...

Page 101: ...rded when the input signal falls below the actual Gating Threshold This can be useful for maintaining a more natural drop in signal level during program fades Gain Freeze When Gain Freeze is selected and the audio falls below the Gating Threshold the gains of the four bands will freeze at their current values and will hold at those values until audio is present that is above the Gating Threshold T...

Page 102: ...ly and does not affect a band s ability to reduce its gain when appropriate AGC Backoff The AGC Backoff adjusts the processing balance between slower AGC action and faster compression Think of it as the density control With the AGC Backoff control set at 0 the audio gain control is primarily due to slower AGC action and therefore short term program dynamics are largely unaffected unless they excee...

Page 103: ...of 120Hz will be quite satisfactory Likewise a High Mid to High frequency crossover of about 4kHz works for most material For fine tuning the sound with different types of program formats some general guidelines can be given For Rock music a slightly lower Low to Low Mid crossover of about 100Hz can put some extra gut into the feel of the music likewise with Dance or music of other formats that co...

Page 104: ...tes in sum and difference mode the crossover frequency settings track both signal chains assuring a stable stereo image at all times AGC Compressor Gain Reduction The curve above is broken into four segments representing the instantaneous gain control for each of the four processing bands The blue line depicts the gain reduction occurring in the slowerAGC while the yellow line depicts gain reducti...

Page 105: ...EM or global parameters which are saved with presets but not restored when presets are taken unless the Input Output Settings Change With Presets check box is checked When this box is checked the following control settings are recalled whenever a preset is recalled From the INPUT Screen Audio Source Analog or Digital Analog Gain Analog AES Gain Digital Balance common to both Analog and Digital Inp...

Page 106: ... when the Input Output Settings Change With Presets check box is unchecked Metering Data Over TCP IP The VP 8ip utilizes the UDP protocol by default for transmitting metering data to the remote GUI TCP with its guaranteed packet delivery is always used for control In some instances UDP packets are blocked by In ternetServiceProviders andwhenthisoccurstheGUI can successfully connect to the VP 8ip b...

Page 107: ... volume control for the headphone output is located on the right side of the front panel and at the lower right of the remote Pro GUI To adjust the headphone volume press and hold the black button to the left of the knob while turning the knob clockwise to increase volume and counter clockwise to reduce it Note The headphone outputs of the VP 8ip are driven by National Semiconductor LM675 power op...

Page 108: ...word can be any combination of characters numbers or symbols If the Remember This Password check box is checked the Pro GUI stores the password on the local PC If you do not check the check box you will be asked for the password the next time you connect since the first round of verification will fail When asked for a password while logging in you can also check the remember box to save what you e...

Page 109: ...hem Note however that because Preset Saves was not checked when this access code was created that person may make changes to a preset but may not save them Pro GUI Lock In the event that security has been enabled by configuring the GUI Access Code Permissions Dialog above then selecting Pro GUI Lock will immediately lock the Pro GUI on the host PC prohibiting access until it has been unlocked with...

Page 110: ...I LOCK The GUI Access Code Permissions box will open 13 Carefully click only the Clear Access Code button Then click OK 14 The GUI Access Code Permissions box will close The GUI Access Code is now removed Status Indicators Temp When the Temp indicator is green the operating temperature inside the VP 8ip is satisfactory When it is red the temperature is too high The displayed value is the current o...

Page 111: ...future To create edit or view entries in the Event Scheduler click the Events button on the System Screen The following Event Scheduler screen will open and the events list will be empty when opened for the first time Creating a Weekly Rotation Event 1 Click the Add button in the Weekly Rotation area of the Event Scheduler window The Weekly Rotation window will open as shown below 2 On the left co...

Page 112: ...vent Adding a new event in the Long Term Rotation scheduler works in a similar manner The Long Term Rotation entry window appears as follows Deleting a Scheduled Event Deleting a scheduled preset change is as simple as adding one Open the Event Scheduler window by navigating to the System menu and clicking Events The Event Scheduler window will open To delete an item in either the WeeklyRotationor...

Page 113: ... be set or changed The VP 8ip system time can be synchronized to external time servers SNTP or Simple Network Time Protocol if desired Alternately time can be synchronized to the PC that is running the Windows based GUI In this instance time updates will occur upon successful connection to the GUI on the remote PC ...

Page 114: ...on readily in succession This is a very direct means of comparing pre sets It is important to remember to save the present settings as a preset before invoking others or they will be lost Note also that you can only select presets that are already loaded in the VP 8ip from this dialog box Save Asmalldialogboxappears whichprompts for a name under which to save the present settings of the VP 8ip The...

Page 115: ...drop allows movement between the library folders and the VP 8ip and its mirror archive in the Pro GUI Devices A list of VP 8ip devices with which the Pro GUI has had cause to become familiar is shown in the Devices dialog box Highlighting the desired VP 8ip s name and hitting Select causes the Pro GUI to attempt to connect to it if you are Online In the event noVP 8ip s are listed or one is adding...

Page 116: ...re that QSave A is highlighted If it is not press its button to highlight it Press the B A button This will copy the contents of QSave buffer A to QSave buffer B Now the contents of both buffers are identical Change some settings on the VP 8ip These settings will automatically be stored in the A buffer Compare your changed settings to the recalled factory preset by pressing the QSave B button Comp...

Page 117: ...UI is in communication with and directly reflects a VP 8ip Offline meaning the GUI and VP 8ip are disconnected and Trying meaning the GUI is attempting to find the VP 8ip on the LAN and connect to it An adjacent button toggles between Online and Offline Devices ThenameoftheVP 8ip towhichtheProGUI is connected or with which it is attempting to connect shows here in amber Double clicking on the name...

Page 118: ...eenindicatesthattheVP 8ip s settings for this preset agree with those in the Pro GUI s mirror archive red indicates a discrepancy Double clicking on the name brings up a Preset Difference parameter by parameter setting by setting comparison list between the current VP 8ip settings and the recalled preset ...

Page 119: ...lection list can be made without affecting signal processing within the VP 8ip itself which can continue to be processing away obliviously Preset list manipulation can be undertaken Online too Importantly any adjustments made on the Pro GUI Offline will not take effect until the VP 8ip is rendered Online again Invoking a preset by double clicking a preset from the box brought up by clicking the Pr...

Page 120: ...the look of the Pro GUI s skin As new skins are released from Wheatstone they will be available for download from the Wheatstone Processing website Exit Exits the Pro GUI program Hardware Menu Items TheHardwaremenutreemaybeaccessedbyright clicking anywhere on the main VP 8ip Control Panel Please note that many of these functions require you to be connected Online to a VP 8ip Sub menu choices inclu...

Page 121: ...will work VP 8ip Hardware Update The VP 8ip hardware is extremely easy to update whenever new firmware becomes available from Wheatstone There is only one file required for hardware updates a file with the extension VBN The VBN VBN stands for Vorsis Binary Nugget This filecontainshighlyencryptedversionsofthemotherboard application code FPGA images and DSP code ToupdatetheVP 8ip rightclickonanyport...

Page 122: ...ar actual text will vary Check once again that the versions match the documentation Then click Yes Dialog boxes similar to the following will pop up as the download progress occurs When the process has finished you will be prompted to reboot the VP 8ip by the prompt below When the VP 8ip reboots the new VBN code will be running in the unit ...

Page 123: ...resets Menu Items The Presets menu tree may be accessed by right clicking anywhere on the main VP 8ip Control Panel Take Brings up the Take Preset dialog box Save Brings up the Save as Presets dialog box Library Brings up the Preset Library dialog box ...

Page 124: ...ltiband Limiter 5 11 Multiband Enable 5 12 Multiband Drive 5 12 Multiband Knee 5 12 Bass Tools 5 13 Drive 5 14 Style 5 14 Frequency 5 14 Output 5 15 Pre Emphasis Selection 5 15 Type 5 15 Location 5 15 Multiband Limiter Adjustments 5 16 Threshold Screen 5 16 Attack Time Screen 5 17 Release Time Screen 5 18 Final Equalization Screen 5 19 FM Look Ahead Limiter 5 20 FM Look Ahead Limiter Controls 5 20...

Page 125: ... 27 Mode 5 27 SCA 1 5 27 SCA 2 5 27 Analog Output 5 27 TX 1 5 28 TX 2 5 28 Pilot Only 5 28 Analog Output and MPX Modes 5 28 VP 8ip AM Process Mode 5 30 Limiters Menu 5 31 Multiband Limiter 5 31 Multiband Enable 5 31 Multiband Drive 5 31 Multiband Knee 5 32 Bass Tools 5 33 Drive 5 33 Style 5 33 Frequency 5 34 Output 5 34 Pre Emphasis Selection 5 34 Type 5 34 Location 5 34 Multiband Limiter Adjustme...

Page 126: ... Analog Output 2 5 45 LF Tilt Correct 5 45 Adjusting the Tilt Corrector 5 46 Digital Output 5 47 De Emphasis 5 47 PreDelay 5 47 VP 8ip FM HD Process Mode 5 48 Limiters Menu 5 48 Multiband Limiter 5 48 Multiband Enable 5 49 Multiband Drive 5 49 Multiband Knee 5 49 Bass Tools 5 50 Drive 5 51 Style 5 51 Frequency 5 51 Output 5 52 Multiband Limiter Adjustments 5 53 Threshold Screen 5 53 Attack Time Sc...

Page 127: ... 5 63 Frequency 5 63 Output 5 64 Multiband Limiter Adjustments 5 65 Threshold Screen 5 65 Attack Time Screen 5 66 Release Time Screen 5 67 Final Equalization Screen 5 68 AM HD Menu 5 69 Codec Bandwidth 5 69 Enable 5 69 HF Protect Freq 5 69 HF Ceiling 5 69 A Note About Attack Time 5 69 HF Recovery 5 70 Hyper Mono 5 70 AM HD Look Ahead Limiter 5 71 AM HD Look Ahead Limiter Controls 5 71 Look ahead L...

Page 128: ...e Vorsis Spectral Energy Gate 5 83 MP3 AAC 48K Menu 5 84 Multiband Drive 5 84 MP3 AAC 48K Look Ahead Limiter 5 84 MP3 AAC 48K Look Ahead Limiter Controls 5 85 Look ahead Limiter Enable 5 85 Lim Limiter Drive 5 85 Attack 5 85 Release 5 87 Delayed Release 5 87 Mono Output 5 87 Phase 5 87 Left Right Reverse 5 88 Analog 5 88 Digital Output 5 88 VP 8ip MP3 AAC 48K Process Mode 5 89 Limiters Menu 5 89 M...

Page 129: ...oller Controls 5 99 Codec Sample Rate 5 99 Low Pass Filter 5 99 Codec Bitrate 5 100 Mask Thresh and Mask Recovery 5 100 Achieving the Proper Settings 5 100 MP3 AAC 48K Look Ahead Limiter 5 102 MP3 AAC 48K Look Ahead Limiter Controls 5 102 Look ahead Limiter Enable 5 102 Lim Limiter Drive 5 102 Attack 5 103 Release 5 104 Delayed Release 5 105 Mono Output 5 105 Phase 5 105 Left Right Reverse 5 105 A...

Page 130: ... operating modes including those that are not specifically spelled out by the names we ve given the six operating modes Mode Behavior Overview Processing presets in the VP 8ip are mode based What this means is that presets are always associated with the mode that was running at the time a preset was saved Said another way if a user saves a preset while the VP 8ip is in its FM mode that preset beco...

Page 131: ...ok ahead algorithms developed by Vorsis condition the audio in a manner that makes it most suitable to be coded by the iBiquity FM HD perceptual codec The audio source for the HD mode look ahead limiter is the output of the four band AGC Compressor AM HD Mode Summary This mode has been optimized to operate favorably with the HDC Hybrid Digital Coding codec a proprietary and lossy audio compression...

Page 132: ...s of the program which increases the perceived quality for the listener Audio Processor Tuning for CODECS We strongly caution the user to never use the sound at the output of the VP 8ip to determine how to tune it for best behavior with a codec or make judgments about the sound quality This is because the work that the VP 8ip must do to fool the codec into producing a better overall audio quality ...

Page 133: ...er for final peak control The AM and FM analog modes utilize if desired an oversampled distortion controlled final clipper which has several available knees to enable the sound of the peak limiting to be customized The FM analog mode also has a DSP based stereo coder which generates the composite baseband signal required for analog FM broadcasting An oversampled composite processor which is used t...

Page 134: ...rs in a manner that allows them to only take care of shorter duration transients that the preceding four band AGC compressor misses For the best musicality with music based program formats we recommend that the limiters not be operated with extremely short attack and release times While the limiters are capable of attacking audio peaks in as short as 100 microseconds we recommend attack times at t...

Page 135: ...or this reason the Multiband Drive control is not labeled in dB but instead is labeled in percent With sane settings of the four band Makeup control the eight band limiter Multiband Drive control will usually be found between 85 and 100 The full adjustment range is 0 to 100 Higher Multiband Drive settings also cause deeper levels of clipping in the main clipper algorithm if the Final Lim Clip Driv...

Page 136: ...ing dynamic gain changes and without generating undesirable intermodulation artifacts in higher frequency signals Its primary purpose is to allow the thumps of kick drums and other percussion in struments to sound natural in their percussiveness without pumping or other undesired artifacts The algorithm operates in left right mode treating both channels identically Our laboratory research on codec...

Page 137: ...rly abrupt and generates low order harmonics The Soft setting operates with a transfer function occupying approximately 2dB of transition amplitude Therefore the control is lesssharpthanthehardsetting generatingmore low order harmonics While the two settings may appear to be almost the same the 1dB difference in transfer ratio creates a significant difference in how the two Bass Tools styles sound...

Page 138: ... may be placed in one of three locations in the signal chain Pre MBLim In this position the selected pre emphasis is placed before the eight band limiter clipper section In this mode the eight band section may be operated as a frequency conscious limiter tailored to the inverse of the selected pre emphasis Pre Limiter Inthispositionthepre emphasisisaftertheeight band section but before the Look Ah...

Page 139: ...the earlier VP 8ip Graphical Interface Operation section Lower settings more negative numbers reduce the threshold causing limiting to occur at lower audio levels Conversely higher thresholds cause limiting to occur at higher audio levels Because of the frequency response contouring in FM pre emphasis it is generally customary to adjust the limiter thresholds according to the limiting sensitivity ...

Page 140: ...ead output limiter if enabled or the final clipper The attack times for each band are adjustable from 0 1 milliseconds 100 microseconds to 100 milliseconds As explained above faster attack times exert more control over waveform excursions while slower attack times allow peaks to escape the limiter section with less control Attack times are generally adjusted to taste keeping in mind that the slowe...

Page 141: ...rt release times can also increase intermodulation distortion the mixing of low and high frequency energy or a muddying of the sound The release times for each band are adjustable from 300 milliseconds down to 3 milliseconds Faster release allows a more rapid recovery after a limiting event while slower release times do the opposite Release times should be adjusted to taste keeping in mind that th...

Page 142: ... boost equalization are recommended once final limiting has been accomplished in the eight band section In fact the adjustment range has been limitedto 3dB 12dBinordertocurtailthetemptationtoperform aggressive equalization where it is the most inappropriate and even this range is quite large considering the effect that can be created Small adjustments in EQ boost on the order of 1dB or 2dB at most...

Page 143: ...d audio peaks could still be missed because their relative time alignment would be identical FM Look Ahead Limiter Controls The graphic on the right shows the controls available for the look ahead limiter The following text describes each control according to function Look Ahead Limiter Enable When this check box is checked the look ahead limiter is enabled Note that the look ahead limiter can be ...

Page 144: ...all range of the control is from 33 milliseconds to 330 milliseconds Delayed Release Controls the secondary slow release of the look ahead limiter and is adjustable from 100 milliseconds to 1 second When Delayed Release is engaged via the Enable check box the limiter will release the first 3dB of gain reduction at the faster Release setting and the remainder of the Release at the Delayed Release t...

Page 145: ...nds of compensating delay in steps of 100 microseconds The Coarse delay is set first to align the analog and HD signals as closely as possible and then the Fine delay control is used to trim the delay to precisely compensate for that in the HD channel Generally it is a good idea to set the Fine delay to midrange before adjusting Coarse delay so that the Fine delay can then be adjusted in small inc...

Page 146: ...r When stereo enhancement is utilized in the program chain or in the audio processor L R energy is naturally increased as this is the purpose of stereo enhancement to exaggerate the stereo image width by increasing the level of L R energy When taken to the extreme the extra L R energy can cause unnatural sounding audio on some program material the hole in the middle effect exaggeration of reverb i...

Page 147: ...ing the BS 412 Controller On IMPORTANT TheMPXPowerControllerisrequiredincertainEuropeancountries and its sole purpose is to reduce loudness and program density If you are not required to use the BS 412 Controller it should be left in the OFF position because turning it on can cause up to a 5dB loudness loss when the control is set to its 0dB position When the BS 412 control is moved away from its ...

Page 148: ...is control does not adjust the level of the digital baseband192 output See TX1 TX2 level controls De Emphasis When the De Emphasis check box is selected it applies complementary de emphasis accordingtoanypre emphasissettingthathasbeenmadeintheLimitersscreen s Emphasis list box PreDelay Checking this box routes the AES input audio directly to the FM processing circuitry effectively bypassing the de...

Page 149: ...setting the Drive control to 3dB puts the Soft clipper right at the threshold of clipping with most program material with settings higher than 3dB driving the clipper harder Note that we do not mathematically remove the higher order harmonics in this clipper like we do in the VBMS section because such harmonics are required in order to make the waveform have a tightly defined peak amplitude Hard C...

Page 150: ...would otherwise disturb the phase relationships between the 19kHz stereo pilotandthe38kHzstereosubcarrierandthereforecausedegradationofstereoseparation Mode The stereo encoder can be operated in Stereo or Mono by selecting the desired operating mode with this switch When in mono the Stereo Pilot is turned off SCA 1 Inputs applied to the SCAconnectors are digitized at 192kHz Prior to being digitize...

Page 151: ...emale BNC connectors assigned to TX 1 and TX 2 both carry line level audio The XLR outputs are electronically balanced and the BNC connectors are single ended unbalanced with a level 6dB below that on the balanced outputs If pre emphasis has been selected in the FM Limiter screen then both sets of outputs are pre emphasized also L R deemph In this mode the twin output level controls seen in MPX mo...

Page 152: ... range of the analog outputs regardless of the operating mode is 80dBto0dB 6dBinMPXmode in0 05dBsteps coveringvirtuallyevery conceivable operating need in the field NOTE A0dB setting of the output level controls results in a 22dBu PEAK output level at the balanced outputs FM ...

Page 153: ... compatible with legacy analog AM stereo systems that require separately limited Sum and Difference audio For L R Stereo applications the outputs are derived from a mathematically perfect L R L R to L R matrix This also means that the VP 8ip has perfect mono compatibility because in Mono mode the L R channel is simply discarded Note In ALL VP 8ip AM presets the default settings in the AM Transmiss...

Page 154: ...mes Please open several of our FactoryAM presets and observe the settings in the eight band limiter section to see what we mean The eight band limiter s operating parameters are fully adjustable in order to accommodateawidevarietyofprogrammaterialandcompetitiveneeds Italso contains the embedded Bass Tools which is tightly integrated within the limiter structure to intelligently control bass progra...

Page 155: ...d release are adjustable as is the overall transfer function knee hardness The knee shape determines how the limiters behave at or near their thresholds of limiting The graphic below illustrates the difference between the two transfer functions In the Hard mode limiting does not occur until the threshold within a band is precisely reached The sound of this setting is more open and free because no ...

Page 156: ...icant harmonic levels above the third or fifth somewhat dependent the Bass Tools Style setting there is no audible downside to using it with coded audio Furthermore the ability to utilize the Bass Tools on both the FM and HD sides of the processor allows the sound to be more evenly matched as receiver based digital to analog crossfades are encountered Drive This control adjusts the amount of Input...

Page 157: ...rol is adjustable between 12dB and 0dB Pre Emphasis Type Pre emphasis is selectable as 50 or 75 microseconds or Flat OFF Location When pre emphasis is enabled it may be placed in one of three locations in the signal chain Pre MBLim In this position the selected pre emphasis is placed before the eight band limiter clipper section In this mode the eight band section may be operated as a frequency co...

Page 158: ...old causing limiting to occur at lower audio levels Conversely higher thresholds cause limiting to occur at higher audio levels Because of the frequency response contouring in AM pre emphasis it is generally customary to adjust the limiter thresholds in somewhat of a sloping fashion according to the limiting sensitivity curve required which can create a multiband frequency conscious limiter of any...

Page 159: ...head output limiter if enabled or the final clipper The attack times for each band are adjustable from 0 1 milliseconds 100 microseconds to 100 milliseconds As explained above faster attack times exert more control over audio peaks while slower attack times allow peaks to escape the limiter section with less control Attack times are generally adjusted to taste keeping in mind that the slower the a...

Page 160: ...the mixing of low and high frequency energy or a muddying of the sound The multiband limiters all have Delayed Release timing built in to minimize unintentional intermodulation distortion The release times for each band are adjustable from 300 milliseconds down to 3 milliseconds Faster release allows a more rapid recovery after a limiting event while slower release times do the opposite Release ti...

Page 161: ...ionarerecommendedoncefinal limiting has been accomplished in the eight band section In fact the adjustment range has been limited to 3dB 12dB in order to curtail the temptation to perform aggressive equalization where it is the most inappropriate and even this range is quite large considering the effect that can be created Small adjustments in EQ boost on the order of 1dB or 2dB at most are suffic...

Page 162: ...entical AM Look Ahead Limiter Controls The graphic below shows the controls available for the look ahead limiter The following text describes each control according to function Look Ahead Limiter Enable When the Look Ahead Limiter Enable is checked the look ahead limiter is enabled Likewise when this check box is not checked final peak limiting is via the distortion cancelled clipper only The look...

Page 163: ...n which can muddy the sound The overall range of the control is from 33 milliseconds to 330 milliseconds Delayed Release Controls the secondary slow release of the look ahead limiter and is adjustable from 100 milliseconds to 1 second The Delayed Release control has no effect unless the Enable check box is checked see below WhenDelayedReleaseisengagedviatheEnablecheckbox thelimiterwillreleasethe f...

Page 164: ...tributes roundness to the audio without sounding harsh and can be quite powerful for certain AM formats when tuned correctly We offer the Firm and Round modes for two reasons 1 they create a different on air sound a sound that may be suitable for a particular application and 2 they may be easier on the transmission system and its passive components than the Hard clipper style Diversity Delay The V...

Page 165: ...justing a delay slider to affect faster adjustment rates or hold down the Ctrl key to achieve finer control If entering a delay time manually keep in mind that the text box expects the manual input to be in milliseconds so a delay of 8 3488 seconds would be entered as 8348 8 AM ...

Page 166: ...hen Tilt Test is checked a clipped sine wave at 50 amplitude is produced that can be used to properly set the low frequency tilt correction for older plate modulated transmitters that require it Bandwidth Offers eight Low Pass Filter selections typically required for AM and Medium Wave applications with the eight selections being Full AM Bandwidth is unrestricted out to 20 kHz 4 5K Restricts the o...

Page 167: ...value The VP 8ip s AM mode is capable of providing dense modulation up to the 150 limit of its Positive Modulation Asymmetry control and peak control in both negative and positive directions is quite good at all settings Caveat 1 It needs to be mentioned that unless the transmitter is either 1 a grossly over designed plate modulated rig or 2 is of recent design and has one of the newer modulation ...

Page 168: ...om 79 95dB or 59 95dBu to 0 00dB or 24 0dBu in 0 05dB steps The output level control should be adjusted to provide the desired negative modulation percentage Positive modulation asymmetry may then be set using the Positive Modulation control LF Tilt Correct Low Frequency Tilt Correction is used to correct either fully or partially for the low frequency response inadequacies of primarily older styl...

Page 169: ...odulate well at low frequencies and the following procedure will determine this 1 Connect the VP 8ip to the audio input of the transmitter to be tested 2 Connect the transmitter to either a dummy load of rated power or to the antenna system 3 Turn on theVP 8ip sTest Oscillator Adjust it to a frequency of 75Hz Adjust the Test Oscillator Level control and the Analog 1 or Analog 2 output as appropria...

Page 170: ...with gross amounts of final clipping in the processor large amounts of bass equalization and positive modulation beyond 100 Doing so or attempting to do so can overstress components in the transmitter leading to overheating and damage or much worse Digital Output Adjusts the peak audio signal level present at the AES EBU digital output The resulting output levels are simultaneously indicated in dB...

Page 171: ...naturalswishingand phasey artifactsthatoutdatedand simplistic multiband algorithms even with fewer bands generate There are no caveats for using the eight band limiter for FM HD though it is probably inappropriate to drive the limiters continuously beyond 3 6dB of indicated gain reduction We recommend operating the limiters in a manner that allows them to do three things gently increase RMS energy...

Page 172: ... term audio density Very high drive settings resulting in more than 6 8dB of continuous gain reduction are typically unnecessary The absolute Multiband Drive control setting is dependent upon the setting of the Makeup control in the four bandAGC s control screen For this reason the control is not labeled in dB Drive but instead is labeled in percent With typical settings of the four band Makeup co...

Page 173: ...undesirable intermodulation artifacts in higher frequency signals Its primary purpose is to allow the thumps of kick drums and other percussion instrumentstosoundnaturalintheir percussiveness without pumping or other undesired artifacts The algorithm operates in left right mode treating both channels identically Our laboratory research on codec behavior rather surprisingly revealed that it is perf...

Page 174: ...abrupt and generates low order harmonics TheSoftsettingoperateswithatransfer function occupying approximately 2dB of transition amplitude Therefore the control is less sharp than the hard setting generating more low order harmonics While the two settings may appear to be almost the same the 1dB difference in transfer ratio creates a significant difference in how the two Bass Tools styles sound on ...

Page 175: ...ls algorithm and can be thought of as a low bass mix control Settings between 6dB and 3 0dB add extra bass to the overall mix while settings lower than 6 0dB reduce it Both the Bass Tools Drive and the Output controls are best adjusted by ear using percussive bass material The Output control is adjustable between 12dB and 0dB FM HD ...

Page 176: ... needed Each of the limiter thresholds can be adjusted separately or in groups according to the manner described in the earlier VP 8ip Graphical Interface Operation section Lower settings more negative numbers reduce the threshold causing limiting to occur at lower audio levels Conversely higher thresholds cause limiting to occur at higher audio levels Note Radically different settings between adj...

Page 177: ...are adjustable from 0 1 milliseconds 100 microseconds to 100 milliseconds As explained above faster attack times exert more control over audio peaks while slower attack times allow peaks to escape the limiter section with less control Attack times are generally adjusted to taste keeping in mind that the slower the attack time the more work the limiter must do while conversely the faster the attack...

Page 178: ...the mixing of low and high frequency energy or a muddying of the sound The multiband limiters all have Delayed Release timing built in to minimize unintentional intermodulation distortion The release times for each band are adjustable from 300 milliseconds down to 3 milliseconds Faster release allows a more rapid recovery after a limiting event while slower release times do the opposite Release ti...

Page 179: ...n are recommended once spectral limiting has been accomplished in the eight band section In fact the adjustment range has been limited to 3dB 12dB in order to curtail the temptation to perform aggressive equalization where it is the most inappropriate Even this range is quite large considering the effect that can be created Small adjustments in EQ boost on the order of 1dB or 2dB at most are suffi...

Page 180: ...limiter with a 0 5 millisecond 500 microseconds look ahead time The control path not the audio path is highly oversampled in order to achieve extremely precise peak control The primary goal of oversampling in the control sidechain is better peak control through finer definition of the audio waveform at the input to the detector Oversampling of the audio signal itself is not only unnecessary but wa...

Page 181: ...rd very accurate peak control but at the expense of musicality and program dynamics Therefore you should always choose the fastest attack time consistent with how you wish the output of the processor to sound realizing that adjusting the limiter for longer attack times will as a consequence of those longer attack times allow some audio peaks to escape uncontrolled How the attack time is adjusted i...

Page 182: ...ayed Release control offers adjustments between 100 milliseconds and 1 000seconds WecannotrecommendaDelayedReleasesettingbelow approximately 160 milliseconds when processing for a perceptual codec An ideal setting for the majority of applications will fall between settings of 300 and 600 milliseconds Phase Reverse When this check box is checked the electrical phase of the left and right signals ar...

Page 183: ...our exclusive fully adjustable eight band AM HD Spectral Limiteralgorithm Thislimiterisespeciallyeffectiveatcontrollingpeakenergy without generating unnatural swishing and phasey artifacts that outdated and simplistic multiband algorithms even with fewer bands generate There are no caveats for using the eight band limiter for AM HD though it is probably inappropriate to drive the limiters continuo...

Page 184: ...ive set tings make the sound more aggressive by increasing short term audio density Very high drive settings resulting in more than 6 10dB of continuous gain reduction are typically unnecessary The absolute Multiband Drive control setting is dependent upon the setting of the Makeup control in the four band AGC s control screen For this reason the control is not labeled in dB Drive but instead is l...

Page 185: ...ng undesirable intermodulation artifacts in higher frequency signals Its primary purpose is to allow the thumps of kick drums and other percussion in struments to sound natural in their percussiveness without pumping or other undesired artifacts The algorithm operates in left right mode treating both channels identically Our laboratory research on codec behavior rather surpris ingly revealed that ...

Page 186: ... is fairlyabruptandgeneratesloworderharmonics The Soft setting operates with a transfer functionoccupyingapproximately2dBoftransi tionamplitude Thereforethecontrolislesssharp than the hard setting generating more low order harmonics While the two settings may appear to be almost the same the 1dB difference in transfer ratio creates a significant difference in how the two Bass Tools styles sound on...

Page 187: ...ss Tools algorithm and can be thought of as a low bass mix control Settings between 6dB and 3 0dB add extra bass to the overall mix while settings lower than 6 0dB reduce it Both the Bass Tools Drive and the Output controls are best adjusted by ear using percussive bass material The Output control is adjustable between 12dB and 0dB ...

Page 188: ...g if needed Each of the limiter thresholds can be adjusted separately or in groups according to the manner described in the earlier VP 8ip Graphical Interface Operation section Lower settings more negative numbers reduce the threshold causing limiting to occur at lower audio levels Conversely higher thresholds cause limiting to occur at higher audio levels Note Radically different settings between...

Page 189: ...liseconds 100 microseconds to 100 milliseconds As explained above faster attack times exert more control over audio peaks while slower attack times allow peaks to escape the limiter section with less control Attack times are generally adjusted to taste keeping in mind that the slower the attack time the more work the limiter must do while conversely the faster the attack time the fewer short term ...

Page 190: ...the mixing of low and high frequency energy or a muddying of the sound The multiband limiters all have Delayed Release timing built in to minimize unintentional intermodulation distortion The release times for each band are adjustable from 300 milliseconds down to 3 milliseconds Faster release allows a more rapid recovery after a limiting event while slower release times do the opposite Release ti...

Page 191: ...qualization are recommended once final limiting has been accomplished in the eight band section In fact the adjustment range has been limitedto 3dB 12dBinordertocurtailthetemptationtoperformaggressive equalization where it is the most inappropriate and even this range is quite large considering the effect that can be created Small adjustments in EQ boost on the order of 1dB or 2dB at most are suff...

Page 192: ... artifacts caused by certain kinds of high frequency program energy The HF Protect control adjusts the frequency where control action begins This control works in concert with the Ceiling control below HF Ceiling The Ceiling control adjusts the audio threshold where the HF Protect algorithm will begin to operate The more negative the control s setting in dB the sooner amplitude domain wise the hig...

Page 193: ...ated regardless of control settings by the user and the input program material The above means that even if a user has set the Recovery control to its fastest possible setting the Recovery algorithm may and will automatically set it slower under certain program circumstances in order to prevent codec induced close in intermodulation products Hyper Mono When this box is checked weak or incorrect L ...

Page 194: ...because their relative time alignment would be identical AM HD Look Ahead Limiter Controls The graphic on the right shows the controls available for the look ahead limiter The following text describes each control according to function Look ahead Limiter Enable When this check box is checked the look head limiter is enabled L R Linked When this box is checked the look ahead limiter s left and righ...

Page 195: ...ster than 50 milliseconds in order to minimize the generation and coding of close in difference frequency intermodulation components that can result from very fast release times The overall range of the control is from 33 milliseconds to 330 milliseconds with an ideal setting for most applications falling between 70 and 130 milliseconds Delayed Release Controls the secondary slow release of the lo...

Page 196: ...ar to be interchanged at the output of the VP 8ip please check this control first to ensure that it is not checked Analog Controls the output amplitude of the analog output signal appearing on the left and right channel XLR connectors on the rear panel This output control can be set to OFF or to levels from 79 95dB or 57 95dBu to 0 00dB or 24 0dBu in 0 05dB steps Digital Output Adjusts the peak au...

Page 197: ... often generate There are no caveats for using the eight band limiter though it is probably unnecessary to drive the limiters continuously beyond 3dB of indicated gain reduction We generally recommend operating the limiters in a manner that allows them to do three things gently increase RMS energy loudness shape the HF spectrum to make it more suitable for the codec medium and control longer durat...

Page 198: ...etting of the Makeup control in the four band AGC s control screen For this reason the control is not labeled in dB Drive but instead is labeled in percent With typical settings of the four band AGC s Makeup control 24dB to 30dB the correct eight band limiter Multiband Drive control setting will usually be between 85 and 95 The full adjustment range is 0 to 100 Higher Multiband Drive settings caus...

Page 199: ...able intermodulation artifacts in higher frequency signals Its primary purpose is to allow the thumps of kick drums and other percussion instruments to sound natural in their percussiveness without pumping or other undesired artifacts The algorithm operates in left right mode treating both channels identically Our laboratory research on codec behavior rather surprisingly revealed that it is perfec...

Page 200: ...upt and generates low order harmonics TheSoftsettingoperateswithatransferfunc tion occupying approximately 2dB of transition amplitude Therefore the control is less sharp than the hard setting generating more low order harmonics While the two settings may appear to be almost the same the 1dB difference in transfer ratio creates a significant difference in how the two Bass Tools styles sound on act...

Page 201: ...algorithm and can be thought of as a low bass mix control Settings between 6dB and 3 0dB add extra bass to the overall mix while settings lower than 6 0dB reduce it Both the Bass Tools Drive and the Output controls are best adjusted by ear using percussive bass material The Output control is adjustable between 12dB and 0dB MP3 ACC 48k ...

Page 202: ...limiting to be created if needed Each of the limiter thresholds can be adjusted separately or in groups according to the manner described in the earlier VP 8ip Graphical Interface Operation section Lower settings more negative numbers reduce the threshold causing limiting to occur at lower audio levels Conversely higher thresholds cause limiting to occur at higher audio levels Note Radically diffe...

Page 203: ...aged leaving them to be controlled solely by the final look ahead output limiter The attack times for each band are adjustable from 0 1 milliseconds 100 microseconds to 100 milliseconds As explained above faster attack times exert more control over audio peaks while slower attack times allow peaks to escape the limiter section with less control Attack times are generally adjusted to taste keeping ...

Page 204: ...d The multiband limiters in the VP 8ip have Delayed Release timing built in to minimize unintentional intermodulation distortion See the graph below for a plot of this behavior note that all gain trajectories are linear The release times for each band are adjustable from 300 milliseconds down to 3 milliseconds Faster release allows a more rapid recovery after a limiting event while slower release ...

Page 205: ...n we allow this to be done is that certain custom audio textures especially in the bass region may be created by purposely operating the lower frequency limiters with extremely fast release times Such settings in effect create distortion on purpose But because the resulting distortion is constrained to the narrow frequency bands within each of the VP 8ip s multiband limiters it is possible to crea...

Page 206: ...ke the MP3 AAC 48K mode in the VP 8ip s MP3 AAC 48K mode the Spectral Energy Gate is fully automatic and therefore requires no special user adjustment Note We strongly suggest that the output of the VP 8ip NOT be used to evaluate the subjective sound quality of the codec system Rather listen to the output of the decoder as this is where sound quality should always be judged This is because in orde...

Page 207: ...n It is duplicated here in order to enable fine adjustments of the eight band limiter s sound withouthavingtotogglebackandforthbetweentheMP3 AAC 48KandLimitersscreens MP3 AAC 48K Look Ahead Limiter TheMP3 AAC 48Koutputmaybeaccuratelypeakcontrolledbyahighly oversampled feed forward limiter with a 0 5 millisecond 500 microseconds look ahead time The control path not the audio path is highly oversamp...

Page 208: ...ed When the box is not checked no peak limiting is performed and the peak output levels will be uncontrolled and therefore undefined Lim Limiter Drive This controls the amount of drive to the look ahead limiter noting that unlike other VP 8ip operating modes there are no clippers available all limiting must be done by the look ahead limiter The gain range of this control is 18dB to 12dB The resolu...

Page 209: ...e VP 8ip are accurately controlled if the attack time is slowed down set to larger numbers in order to create a sound that is more open and less restrained then due consideration must be given to the resulting peak output levels Why 1 If the Digital and or Analog output controls are operated near their maximum output levels and the look ahead limiter is operated with slow attack times clipping wil...

Page 210: ...uce intermodulation distortion permitting deeper limiting depth without incurring an intermodulation distortion penalty Use of the Delayed Release mode is always recommended when processing ahead of a perceptual codec As we discussed before very fast limiter release times can generate close in intermodulation products around desirable program signals which can degrade the perceived quality of the ...

Page 211: ... right channel XLR s on the rear panel This control can be set to OFF or to levels from 79 95dB or 57 95dBu to 0 00dB or 24 0dBu in 0 05dB steps Digital Output Adjusts the peak audio signal level present at the AES EBU digital output The resulting output levels are simultaneously indicated in dBFS by the front panel and remote GUI bargraph meters This control can be set to OFF or adjusted over the...

Page 212: ...tingunnaturalswishingand phasey artifactsthatoutdatedand simplistic multiband algorithms usually generate There are no caveats for using the eight band limiter other than it is inappropriate to operate the limiters continuously beyond 3dB of limiting when used with codecs We generally recommend operating the limiters in a manner that allows them to do three things gently increase RMS energy loudne...

Page 213: ...and Drive settings create a more gentle sound while still controlling program energy whilehigherMultibandDrivesettingsmakethesoundmore aggressive by increasing short term audio density Very high drive settings resulting in more than 6 8dB of continuous gain reduction in any band is typically unnecessary as well as undesired The Multiband Drive control setting is also somewhat dependent upon the se...

Page 214: ...mpressors than multiband limiters Bass Tools Vorsis Bass Tools allows extremely low program frequen cies to be processed without causing dynamic gain changes and without generating undesirable intermodulation artifacts in higher frequency signals Its primary purpose is to allow the thumps of kick drums and other percussion instruments to sound natural in their percussiveness without pumping or oth...

Page 215: ...ly abrupt and generates low order harmonics The Soft setting operates with a transfer function occupying approximately 2dB of transition amplitude Therefore the control is less sharp than the hard setting generating more low order harmonics While the two settings may appear to be almost the same the 1dB difference in transfer ratio creates a significant difference in how the two Bass Tools styles ...

Page 216: ... Bass Tools algorithm and can be thought of as a low bass mix control Settings between 6dB and 3 0dB add extra bass to the overall mix while settings lower than 6 0dB reduce it Both the Bass Tools Drive and the Output controls are best adjusted by ear using percussive bass material The Output control is adjustable between 12dB and 0dB ...

Page 217: ...e adjustable over a 10dB range permitting frequency conscious limiting to be created if needed Lower Threshold settings more negative numbers reduce the threshold causing limiting to occur at lower audio levels Conversely higher thresholds cause limiting to occur at higher audio levels Note Radically different settings between adjacent bands won t cause strange sounds there is no swishing possible...

Page 218: ...tack times for each band are adjustable from 0 1 milliseconds 100 microseconds to 100 milliseconds As explained above faster attack times exert more control over audio peaks while slower attack times allow peaks to escape the limiter section with less control Attack times are generally adjusted to taste keeping in mind that the slower the attack time the more work the final limiter must do Convers...

Page 219: ...xing of low and high frequency energy or a muddying of the sound The multiband limiters in the VP 8ip have built in Delayed Release timing to minimize unintentional intermodulation distortion See the graph below for a plot of this behavior The release times for each band are adjustable from 300 milliseconds down to 3 milliseconds Faster release allows a more rapid recovery after a limiting event w...

Page 220: ...s especially in the bass region may be created by purposely operating the lower frequency limiters with extremely fast release times In effect such drastic settings create harmonic and narrow band IM distortion But because the resulting distortion is constrained to the quite narrow frequency bands of the VP 8ip s multiband limiters it is possible to create aesthetically pleasing warmth on the low ...

Page 221: ... sophisticated audio processing algorithm the exclusive Spectral Energy Gate is tailored specifically for use with low bitrate perceptual codecs Though it can be utilized with all audio codecs it really shines when used in combination with codecs operating at bitrates below approximately 48kBPS The VP 8ip s Spectral Energy Gate is a complex multiband control structure for managing audio program en...

Page 222: ...sition for codecs operating at those sample rates Sample rates lower than 22 05kHz may benefit most from the use of the 44 1 22 05kHz setting Low Pass Filter The purpose of the low pass filter is to remove program energy higher than the frequency selected by the control By removing audio energy above a certain frequency highersubjectiveaudioqualitycanbeachievedbythecodecwhenoperatingata particular...

Page 223: ... interaction between the Mask Thresh and Mask Recovery controls although achieving the proper settings is easy if the following guidelines are used First set the Codec Bitrate control according to the bitrate being used Next set the Mask Recovery control to 330mS and the Mask Thresh control to 0dB Then adjust the Mask Thresh control counter clockwise until the onset of high frequency dulling is ju...

Page 224: ... to the codec in such a way that it sounds better at the output of the decoder the output of the VP 8ip might not sound very pleasing This is no cause for concern simply use the output of the decoder as the sound quality reference The upside of the above is that maximum possible sound quality will be extracted from the encode decode process The downside of the above is that the latency through the...

Page 225: ...inishing returns is rapidly reached our lab research revealed that oversampling the control signal by more than about 4x over the audio has no real benefit in an audio application Note that if the audio and the control signals were both oversampled peaks would be missed again because their relative time alignment that is peaks occurring between samples would be identical to the non oversampled cas...

Page 226: ...ead which is always active The full adjustment range is 0 2mS to 100mS Very fast attack times afford accurate peak control at the expense of musicality Always choose the fastest attack time consistent with how you wish the output of the processor to sound realizing that adjusting the limiter for longer attack times will allow some audio peaks to escape uncontrolled How the attack time is adjusted ...

Page 227: ...output level controls is valid only when the look ahead limiter is being operated with an attack time of 0 5 milliseconds or less which ensures that the peak output level is being defined by the peak limiter s threshold and not by some arbitrary program related overshoot caused by limiter attack times that are simply too slow Release Release controls the primary fast release time of the look ahead...

Page 228: ...ay degrade the perceived quality of the audio at the output of the codec more than just the action of the codec or limiters themselves would imply The use of Delay Release mitigates this distortion improving the sound of the codec at any practical bitrate The Delayed Release control offers adjustments between 100 milliseconds and 1 000 seconds thoughwedonotrecommendDelayedReleasesettingsbelow appr...

Page 229: ...ital Output Adjusts the peak audio signal level present at theAES EBU digital output The resulting output levels are simultaneously indicated in dBFSbythefrontpanelandremoteGUIbargraphmeters Thiscontrol can be set to OFF or adjusted over the range of minus 35 95dBFS to 0dBFS Peak Output Level Note As mentioned previously the peak level accuracy that is the calibration of the output level controls ...

Page 230: ...page A 1 VP 8IP Sept 2013 A P P E N D I X Appendix Parameters Units and Ranges A 2 Contents ...

Page 231: ...l amplitude of 2V and minimum allowable input signal amplitude of 200mV Input Gain Adjustment Ranges Gain Adjustment 36dB to 12dB Gain Adjustment Increments 0 5dB Gain Calibration A gain control setting of 0 0 aligns an external 0dBFS signal with the VP 8ip s 0dBFS internal reference Input Failsafe Type Automatic Analog Fail Cause Audio level below 48dBFS Response Time 30 seconds Digital Fail Caus...

Page 232: ...or matrix mode with the gain linked at AGC time constants Drive Gain 79 0dB to 6 0dB in 0 5dB steps plus OFF Makeup Gain Range 18 0dB to 24 0dB 0 5dB steps AGC Compressor Thresholds 35dBFS to 65dBFS AGC Threshold Backoff 0dB to 6dB AGC Attack 50mS 1500ms 1 5 sec AGC Release 100mS 7 0 seconds AGC Band Coupling 0dB to 6 0dB 0 5dB steps Compressor Attack 3 0mS 1000mS 1Sec Compressor Release 20mS 1000...

Page 233: ...uS 75uS Pre emphasis insert points Pre MB Limiter Pre look ahead limiter Post look ahead limiter pre clipper Look Ahead Limiter Attack 0 2ms 100ms Look Ahead Limiter Release 33ms 330ms Look Ahead Limiter Delayed Release 100ms 1000ms 1Sec Main FM Clipper Styles Hard Firm Round De emphasis Complementary as applied in pre emphasis Stereo Encoder FM Mode Only Reference grade stereo encoder with embedd...

Page 234: ...eband192 Analog Analog Left Right Analog Left Right De emphasized Composite Multiplex TX1 and TX2 Test Oscillator Waveform Sine Wave Frequencies 50Hz to 80kHz plus 31 25kHz Bessel Output Level 0 to 100 in 1 0 steps Digital Output Level 35 90dB to 0 0dB or OFF Eight Band AM Output Peak Limiter A four band parametric EQ follows the eight band limiter and feeds the Bass Tools with multiple operating ...

Page 235: ... 10kHzNRSC 7 5kHz 6 5kHz 6kHz CCIR 5 5kHz 5kHz and 4 5kHz Output Mode Mono Stereo Stereo M S Positive Modulation 100 to 150 in 1 steps Digital Output AES 3 pin XLR digital and Stereo pre or post Diversity Delay pre or post DeEmphasis Test Oscillator Waveform Sine Wave Clipped Sine Wave Frequencies 25Hz to 12kHz Level 0 to 100 in 1 0 steps Tilt Test Provides clipped sine wave at 50 of the Level amp...

Page 236: ...ools Style Soft Hard Bass Tools Output 12 0 0 0dB Bass Tools Frequency 60 300Hz Multiband Knee Soft Hard Multiband Threshold 10dB relative to Drive Multiband Attack 0 1ms 100ms Multiband Release 3ms 300ms Look Ahead Limiter Attack 0 2ms 100ms Look Ahead Limiter Release 33ms 330ms Look Ahead Limiter Delayed Release 100ms 1000ms 1Sec FM HD Output Screen Controls Phase 0 or 180 degrees Left Right Rev...

Page 237: ...band Knee Soft Hard Multiband Threshold 10dB relative to Drive Multiband Attack 0 1ms 100ms Multiband Release 3ms 300ms Look Ahead Limiter Attack 0 2ms 100ms Look Ahead Limiter Release 33ms 330ms Look Ahead Limiter Delayed Release 100ms 1000ms 1Sec AM HD Output Screen Controls Bandwidth Off and 16kHz to 4kHz in 1kHz steps HF Protect 16kHz to 3kHz in 1kHz steps Ceiling 0dB to 48dB in 0 5dB steps HF...

Page 238: ...12 0 0 0dB Bass Tools Frequency 60 300Hz Multiband Knee Soft Hard Multiband Threshold 10dB relative to Drive Multiband Attack 0 1ms 100ms Multiband Release 3ms 300ms MP3 AAC 48K Screen Controls Multiband Drive clone from previous screen 0 100 Limiter Drive 18 12dB Look Ahead Limiter Attack 0 2ms 100ms Look Ahead Limiter Release 33ms 330ms Look Ahead Limiter Delayed Release 100ms 1000ms 1Sec Phase ...

Page 239: ...0dB relative to Drive Multiband Attack 0 1ms 100ms Multiband Release 3ms 300ms MP3 AAC 48K Screen Controls Multiband Drive clone from previous screen 0 100 Codec Sample Rate 48 32 24K 44 1 22 05K Low Pass Filter OFF 16 to 4kHz 1kHz steps Codec Bit Rate 64 48 32 24 20 18 kBPS Mask Threshold 0 48dB 0 5dB steps Recovery 33ms 330ms Limiter Drive 18 12dB Look Ahead Limiter Attack 0 2ms 100ms Look Ahead...

Page 240: ...ling Aweekly preset scheduling establishes a weekly cycle of preset changes allowing for automatic programmed day by day exclusions or additions Additionally a separate long term scheduling table permits the establishment of one off preset changes for any future time and date General Purpose Input GPI Eight optically isolated inputs are slaved to the first eight preset slots Presets may be recalle...

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