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APA-4E8 Operator’s Manual  

 

 

 

 

 

 

 Page 33 

 

ta

x

 

Amp Channel Loads 

 

In addition to the more obvious 24 bit 96k analogue to digital converters (ADCs) fitted to the 
inputs of your amplifier for analogue signal conversion, your APA has has eight additional 
ADCs of the same quality fitted directly at the output terminals.  These are used to monitor 
the speaker output voltages and currents in real time and are fed directly back into the DSP, 
so near-instantaneous monitoring of power and distortion can be realised.  This hardware 
addition is crucial to the adaptive nature of your APA.   
 
It also permits real time monitoring of the load impedances using this metric display. 
 
 
 

 

 
 
 
 
 
 
 
 

The first time this user metric display is shown after power up, it will display “---“ in place of 
a measured impedance, until voltage and current data at a sufficient level has been collected. 
This may take a few seconds, and the measurement algorithm is weighted to respond to 
instantaneous drops in impedance so that over current protection can operate quickly to 
prevent damage to output circuitry. 
 
 
 
 
 
 
 
 
 
 
 
 
If the level on any channel drops below the threshold for accurate readings to be taken, the 
pervious value will be held and shown in parenthesis as below, where channels 2 and 4 reads 
are now not live. 
 

 

 

Содержание apa-4e8

Страница 1: ......

Страница 2: ...Page 2 APA 4E8 Operator s Manual ta x...

Страница 3: ...ING YOUR APA INSTALLING YOUR APA INSTALLING YOUR APA 11 11 11 11 Unpacking 11 Electrical Considerations 12 Mechanical Considerations 13 CONNECTING TO YOUR A CONNECTING TO YOUR A CONNECTING TO YOUR A C...

Страница 4: ...iter Threshold 37 Output Polarity Phase Reverse 37 System Menu 38 Overview 38 UNDERSTANDING YOUR A UNDERSTANDING YOUR A UNDERSTANDING YOUR A UNDERSTANDING YOUR APA PA PA PA 39 39 39 39 Memories Preset...

Страница 5: ...ER YOUR APA PA PA PA 57 57 57 57 Maintenance 57 Warranty 57 PERFORMANCE OF YOUR PERFORMANCE OF YOUR PERFORMANCE OF YOUR PERFORMANCE OF YOUR APA APA APA APA 58 58 58 58 Technical Specifications 58 Gene...

Страница 6: ...IV Boost Below 66 Appendix II Program Limiter and Peak Limiter 67 Program Limiter 67 Peak Limiter 68 Setting Accurate Limiter Thresholds Program Limiter 70 Setting Accurate Limiter Thresholds Peak Li...

Страница 7: ...conditions protecting drivers and significantly enhancing performance from all speaker systems The power stages and processing tightly integrate with the power supply featuring 96k analogue to digita...

Страница 8: ...om the apparatus 11 Only use attachments accessories specified by the manufacturer 12 Use only with the cart tripod bracket or table specified by the manufacturer or sold with the apparatus When a car...

Страница 9: ...eli l appareil cela est galement valable pour une ventuelle rallonge lectrique 11 Utilisez exclusivement des accessoires et des appareils suppl mentaires recommand s par le fabricant 12 Utilisez exclu...

Страница 10: ...at the following products Kind of equipment Audio Amplifier Commodity Code 8518408990 Type Designation APA 4E8 is manufactured in accordance with EMC Directive 2004 108 EC in compliance with the follo...

Страница 11: ...he unit please check it carefully for any damage If any is found immediately notify the carrier concerned you the consignee must instigate any claim Please retain all packaging in case of future re sh...

Страница 12: ...breaking distances For safety reasons THE EARTH LEAD SHOULD NOT BE DISCONNECTED IN ANY CIRCUMSTANCE If ground loops are encountered consult the section on connecting your amplifier on page 14 The wir...

Страница 13: ...ting the amplifier in a rack or enclosure Be aware that THE FRONT PANEL IS NOT CAPABLE OF SUPPORTING THE UNIT ON ITS OWN Make sure that the rear of the unit is adequately supported The depth of the fr...

Страница 14: ...d still be twin core plus screen PIN1 Screen connected to the chassis of the unbalanced equipment or left disconnected at the unbalanced end PIN2 Hot signal PIN3 Cold ground 0V NOTE This amplifier is...

Страница 15: ...performance the speaker cables should be kept as short as possible and conform to the following minimum requirements APA 4E8 22 Amps into 4 Ohm speaker loads When operating the amplifier into loads o...

Страница 16: ...ough User Metrics from the Home Screen 5 Mute Keys These will mute the output channel processing sections of the amplifier They do not affect input processing or audio sent back out on the network Ple...

Страница 17: ...network AUD1 Illuminates when a connection is made from the AUD1 audio Ethernet socket on the rear panel to a valid network AUD2 Illuminates when a connection is made from the AUD2 audio Ethernet soc...

Страница 18: ...a valid Ethernet network for transmission of audio data 7 Input Status LEDs This group of 4 tricolour LEDs can show various information about signal level or lock status in AES mode Please see page 1...

Страница 19: ...A and C will show digital input status and sample rate The choice of AES or analogue may be selected remotely on a pair by pair basis so A B can still be showing analogue level with C showing digital...

Страница 20: ...Page 20 APA 4E8 Operator s Manual ta x Signal Paths and Block Diagram...

Страница 21: ...for emergency evacuation messaging This is enabled by either a contact closure on the local amplifier or by a network message Please see the section on page 47 for more information AES Inputs APA can...

Страница 22: ...be configured to run a 4 way system as one half of a stereo set up This would mean that three of the four available input processing paths would remain unused This need not be the case of course as th...

Страница 23: ...ng adjustable Q phase shift Phase 90 degree shift with adjustable frequency Notch Bandpass The operation and use of these different types is covered in Appendix III starting on page 72 Dynamic EQ 3 ba...

Страница 24: ...our network audio outputs that can then be used externally to the amplifier by other devices not just APA Note that this is a full mix matrix different to the input switcher signals from any source ca...

Страница 25: ...nkwitz Riley The high and low pass filters are independent so allowing for asymmetrical crossovers to be realised PEQ EQ 9 bands of parametric equalisation are available on each input channel Each ban...

Страница 26: ...release time constants may be automatically set if desired according to the high pass crossover frequency for a particular channel Peak Limiter The peak limiter is the last processing block in the si...

Страница 27: ...djust these before you switch on To power up hold the Power Home button for 3 seconds the display will wake up and you will see the countdown on screen The Power Home button will change to green and t...

Страница 28: ...to see the countdown at which point the amplifier will go into standby and the output relays will disengage and the main power supply PSU will power down The display will briefly show Before the scree...

Страница 29: ...e its own local IP address Please see the section about connecting to a network starting on page 54 The Monochrome Concept To make your APA as intuitive and simple as possible to operate we have desig...

Страница 30: ...operation or goes too high for safe operation the voltage portion of the screen will change to red and the ALARM LED on the front panel will illuminate Depending on how low the mains voltage drops the...

Страница 31: ...er s temperature rise to a dangerous level the relevant portion of the screen will change to red and the ALARM LED on the front panel will illuminate Individual channels temperatures can cause the amp...

Страница 32: ...ype by turning the encoder when on this screen and choose between analogue inputs as above or AES inputs or network inputs Note that this is NOT the method for choosing inputs and switching between th...

Страница 33: ...crucial to the adaptive nature of your APA It also permits real time monitoring of the load impedances using this metric display The first time this user metric display is shown after power up it wil...

Страница 34: ...ode and manual mode Auto scrolling mode will switch to the next metrics screen every 5 seconds and will include the home screen in this loop Auto scrolling enabled is shown by the small auto in the to...

Страница 35: ...ore level on the meter They also show gain reduction once a channel s level has exceeded the limiter threshold by changing colour and wrapping round beginning to read downward from the top in red So t...

Страница 36: ...ts with the quick gain trim so that it s easy to adjust this with just a single button press Navigation through the list is with the BACK and NEXT keys Press the EDIT button again to exit or press the...

Страница 37: ...nce If there is no name in the system preset the display will show Output X settings as appropriate Limiter Threshold The selected output channel s RMS limiter threshold is shown for reference only an...

Страница 38: ...emories UNIT SUB MENU Unit Info check firmware version and system information IP Address Setup automatic or fixed manual IP selection Identify Unit flash LED meters to highlight a unit in a rack Mains...

Страница 39: ...ts preset format should be in this folder to sync presets wav wav file for emergency voice evac single file title evac wav in this folder logs performance and error logs for diagnostic use only USB Fl...

Страница 40: ...need to reformat it for FAT32 remember that you will lose all data stored on the drive Right click on it in your file manager and choose format and make sure File System is selected to FAT32 as below...

Страница 41: ...firmware presets and wav folders into the same folders on the SD card in the amplifier This direction is used for updating the amplifier firmware or uploading presets onto an amplifier SD USB This wil...

Страница 42: ...for details including sources for input channels MATRIX Mix matrix settings for power amp processing and network outputs POST MATRIX PROCESS All post matrix processing for power amplifier outputs see...

Страница 43: ...ecall In the example above the memory highlighted 2 way LoHi Subs 3 4 AES A contains data about the input source AES Analogue selection Routing Matrix data and Output Processing data The memory above...

Страница 44: ...orrect or old firmware versions being accidentally copied to the amplifier The USB utility is available through the main menu but ONLY IF THE AMPLIFIER IS IN STANDBY To leave the screen and metering a...

Страница 45: ...USB stick onto the amplifier s SD card use the encoder to highlight the USB SD option and press ENTER Any files in the firmware folder on the USB flash drive that are not already in the corresponding...

Страница 46: ...e BACK and NEXT keys to choose the latest version and press ENTER to start the process The current settings will be backed up first followed by an integrity check on the file and then it will overwrit...

Страница 47: ...the overall level These limiters have very slow attack and release times so their effect is more like gentle gain control than dynamic limiting and so has a very benign effect on the audio It can be a...

Страница 48: ...lled by pressing the Power Home button briefly Default Audio Your APA can be reset to a basic 4 in 4 out configuration fed from analogue inputs and all user accessible features restored to defaults Li...

Страница 49: ...the Identify function which can be cancelled by toggling it in the menu or briefly pressing the Power Home button Press MENU and navigate to the entry in the UNIT SUB MENU Pressing ENTER will ask for...

Страница 50: ...gnal is presented on GPI 1 playback will commence and repeat indefinitely until the trigger signal is removed Playback level is adjusted by using the AES C D level control in the remote software It is...

Страница 51: ...ress ENTER if correctly entered the amplifier will report success and then the security level can be changed to 1 To do this select the Toggle Security option and press ENTER to change to level 1 Pres...

Страница 52: ...w the amplifier behaves For example incoming mains voltage especially if being fed from a generator ambient air temperature and air flow around the amplifier More obvious factors will also affect oper...

Страница 53: ...power cycle and contact XTA if continues to appear Status Mains V Low Safed Yes all outputs Mains now too low for satisfactory operation Increase mains voltage and amplifier will restart Status Mains...

Страница 54: ...esponsible for assigning amongst other things IP addresses to connected clients This server functionality may be implemented in your network router or be running as an application on your network s se...

Страница 55: ...valid DHCP Server has replied This is indicated by the IP address that is shown changing from 0 0 0 0 to something of the form 169 254 99 4 the leftmost pair of octets not being the normal 192 168 fo...

Страница 56: ...e levels or power home to get back to the home screen Note that the manual IP address will not be shown on the home screen until a valid network connection is established CTRL LED is illuminated Refer...

Страница 57: ...of the amplifier may be cleaned with a lightly dampened cloth do not use any solvents as they will damage the paint finish and could remove printing If you have any doubts about carrying out maintenan...

Страница 58: ...er Half Bridge Channel 180V Peak Usable Output Voltage per Full Bridge Channel 360V Peak Usable Output Current per Channel 72A Maximum output power All channels driven all channels running pink noise...

Страница 59: ...er Average mains current draw user adjustable System Pre sets Over 100 System latency Analogue In to Speaker Out 1 25mS AES In to Speaker Out 1 64mS Storage Losses Parameter Value Stored Charge 7 5 Co...

Страница 60: ...00W 4 Ohms 14800W 2 x 7400W All channels driven 25mS 80Hz sine wave power burst at 150BPM with 10dB crest factor with all channels run simultaneously over an hour assuming 20 degree ambient Test type...

Страница 61: ...ur assuming 20 degree ambient Test type 1 16 Ohms 2400W3 8 Ohms 2400W3 4 Ohms 2400W3 Single channel driven RMS sine wave medium term continuous power per single channel over 60 seconds assuming 20 deg...

Страница 62: ...These typically consist of one or two cycles of low frequency energy around 80Hz followed by decay and then a string of ongoing repeats or beats To simulate this we have chosen to measure using burst...

Страница 63: ...the signal has been compressed to 10dB or 2 1 Uses of Cut Above mode Traditional use of frequency conscious compression is to control or tame a certain band of frequencies within the program material...

Страница 64: ...of gain reduction applied depends on how much the signal drops the threshold and the ratio set a 2 1 ratio would mean that for every drop of 1dB below the threshold the band centred around 1kHz would...

Страница 65: ...signal levels allows some very effective emphasis of certain parts of the spectrum to be added without the side effect of a permanent audible peak Adding some top end sparkle try picking out high hat...

Страница 66: ...Boost Below mode One of the best uses of this mode is in the area of voice levelling and clarification Placing the filter at about 700Hz lower to nearer 600Hz for men up to 800Hz for women children w...

Страница 67: ...d awful In particular as with all limiters using too fast an attack or release time will result in excessive low frequency distortion There is provision within the remote software application to set a...

Страница 68: ...nels on his desk reach an unacceptably high level he will turn it down appropriately There is a hidden sidechain in operation even in this case The main signal path is fed through the monitor desk and...

Страница 69: ...utput from the unit does not suffer from the overshoot problem Remember that this delay is only in the order of tens of microseconds and is a pre delay the sidechain is moved back in time in relation...

Страница 70: ...ntly long to avoid the limiter itself modulating the program Be intelligent enough to adjust the envelope of the limiter according to the frequency content of the program material The APA RMS limiters...

Страница 71: ...inition of how it is measured If AES power is quoted then it normally is paired with the Program rating and so the calculation of the threshold for the peak limiter is still valid Setting Appropriate...

Страница 72: ...g section Standard Parametric EQ The standard parametric band has adjustable frequency Q or Bandwidth and Gain controls These affect a range of frequencies symmetrically about the centre freqency as s...

Страница 73: ...requencies affected Note that Q settings above 0 75 will result in slight overshoot in the filter response as seen at the highest setting to the right This is normal behaviour and does not indicate in...

Страница 74: ...Note that the response is fundamentally NOT a flat topped response so it is not constructed from a high pass and low pass See previous page for details of how to construct a flat topped filter respons...

Страница 75: ...er the Q the faster the transition Phase Filter The phase filter has adjustable frequency and phase shift controls This introduces a phase shift that gradually changes from 180 above the centre freque...

Страница 76: ...ow Q settings show less overshoot at the turnover frequency but also slower roll off Remember that Q is 1 Bandwidth so the higher the Q the lower the Bandwidth and the smaller the range of frequencies...

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