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© 2001 Gentner Communications Corporation. All rights reserved. Information in this document subject to change without notice. 

803-151-101 Revision 1.0

XAP 800

White Paper

Summary of Contents for XAP 800

Page 1: ...XAP 800 White Paper ...

Page 2: ... Connections 50 13 XAP TH1 Telephone Interface 53 Appendices 54 XAP 800 White Paper Gentner Part No 803 151 101 May 2001 Rev 1 0 2001 Gentner Communications Corporation All rights reserved No part of this document may be reproduced in any form or by any means without written permission from Gentner Communications Corporation Printed in the United States of America Gentner Communications Corporatio...

Page 3: ... centers and courtrooms to training rooms and boardrooms A quality teleconferencing experience is one where the audio or audio source material is the message not the audible inadequacies of a poorly designed or configured teleconferencing system With a properly configured XAP 800 participants and observers do not become fatigued by reverberated audio which reduces sound clarity For ease of use the...

Page 4: ... Ease of design and installation For more information about installing and configuring the XAP 800 refer to the XAP 800 Installation and Operation Manual This document outlines the features functions applications and technical details of the XAP 800 Some of the diagrams included here depict other Gentner products such as the XAP TH1 Telephone Interface APV200 IP Video Codec and PA870 Power Amplifi...

Page 5: ...ine output channels All output levels are adjustable and can be muted 12 x 12 matrix mixer with level control at the cross points Any combination of inputs can be routed to any combination of outputs Adjustable automatic mic mixer 8 channel automatic mix mixer Up to 4 mixers operate across bus 4 internal mixers 4 global mixers linked across Expansion Bus Adjustable parameters Look ahead gating to ...

Page 6: ...Phantom Power On Off Mic 55 25 Line Mic 55 25 Line Mic 55 25 Line Mic 55 25 Line Mic 55 25 Line Mic 55 25 Line Mic 55 25 Line Matrix Input Processing Input Processing Input Processing Input Processing Input Processing Input Processing Input Processing Assignable Processing Assignable Processing Assignable Processing Assignable Processing Assignable Processing Assignable Processing Assignable Proce...

Page 7: ...s volume muting preset change room combining etc Devices can be connected to either port Figure 3 XAP 800 Rear Panel Connections 1 2 3 4 5 6 7 8 9 TECHNICAL SUPPORT 1 800 283 5936 USA OR 1 801 974 3760 PRODUCT DESCRIPTION FRONT PANEL 6 Figure 2 XAP 800 Front Panel 1 LCD Used for numeric display of audio levels gain readouts and limited set up and programming functions 2 Enter ESC Used to navigate ...

Page 8: ...uses based on their capabilities and default settings O R Buses These four audio buses are defaulted as the mic mix buses they can communicate the NOM count see page 25 across the network to other XAP 800s Otherwise these buses are identical to buses S Z S Z Buses These eight buses are defaulted as auxiliary mix buses They are used to route auxiliary audio such as from a CD player video codec such...

Page 9: ...0 10 10 30 30 30 30 1 2 3 4 5 6 7 8 Mic On ic On 0 AP 8 0 Transmit ansmit Rec eceiv eive On On Off ff H AP T 1 XAP TH1 T elephone Interface APV200 IP Videoconferencing Codec with RS 232 Control Figure 4 Typical XAP 800 Installation simplified for illustrative purposes Equipment Placement The XAP 800 is designed for mounting in a 19 equipment rack Do not block any of the ventilation holes With a de...

Page 10: ...oustic echo canceller An acoustic echo canceller samples audio coming in from the remote site and prevents this audio from being sent back to the originating site To be most effective each site should utilize an echo canceller There are several factors that contribute to poor echo cancellation These include Poor room acoustics High reverberation High noise Rapidly changing acoustical environment W...

Page 11: ...m Echo Cancelled Audio Acoustic Echo Microphone Mixer Sample Figure 5 Single Echo Canceller The XAP 800 s Distributed Echo Cancellation places an echo canceller on each mic input for dramatically improved echo cancellation see Figure 6 In this example audio from a distant room is sampled This audio is a reference for each echo canceller on every mic When sampled audio acoustic echo is detected by ...

Page 12: ...gle echo canceller covering the entire room an echo canceller is put on every acoustic mic input In a room of eight microphones a DEC system would have eight echo cancellers Each echo canceller must work only on one acoustic reference Obviously such an echo canceller has a far easier time canceling echo than a single echo canceller with eight acoustic references In addition when compensation techn...

Page 13: ...ellation also ensures that your entire system functions more efficiently Noise not only interferes with human communication it unnecessarily hampers all sound system components i e DSPs amplifier power loudspeaker bandwidth thereby significantly decreasing a system s power and responsiveness By reducing signals unassociated with human speech the XAP 800 ensures the entire system sounds clearer and...

Page 14: ...roblem frequencies could be attenuated in each mic input or both mics could be assigned to processing block A where problem frequencies are attenuated In the future other microphones can also be routed to the same processing block and will therefore receive the same feedback cancellation without any additional adjustments Microphones not routed to processing block A would be unaffected by these fi...

Page 15: ...ters are also excellent for use in canceling out frequency ranges that cannot be transmitted through telephone lines thereby freeing up the system s resources The XAP 800 features the following filters All Pass A filter that provides only phase shift or phase delay without significantly changing the magnitude of the signal Useful in custom crossovers designed to compensate for loudspeaker driver d...

Page 16: ...esigned by overlapping high pass and low pass filters For example the bottom end of a frequency range might be defined as 400Hz and lower This signal might then be heavily compressed and sent to bass bins and woofers powered by amplifiers The midrange say 400Hz to 5kHz can be sent to full range loudspeakers The high end say 5kHz and above can be directed to smaller amplifiers and associated tweete...

Page 17: ...rovement over the previous 3rd order 18 dB octave Butterworth standard It consists of a cascaded 2nd order Butterworth low pass filter and is considered the de facto standard for professional active audio crossovers The XAP 800 also has an intuitive filter display which shows the aggregate filter response in a particular processing block This display can also overlay the filter responses of other ...

Page 18: ...ration Additionally while monitoring numeric dBu audio levels input and output gains can be adjusted for optimum audio performance Inputs 1 8 Balanced audio is input at the rear panel Phoenix connector Mic or line level is selected and phantom power is provided if required The XAP 800 then converts this audio from analog to digital for processing by the DSP engine Once converted to digital audio i...

Page 19: ...trix for outputs that need direct audio The final stage automixing determines how the audio is directed into the post gating input to the routing matrix Each input can be set for a variety of automixing functions including activation settings chairman mic and adaptive ambient mode The functions determine when how and why an individual microphone will gate on or off Microphone Activation There are ...

Page 20: ...ow you to set minimum and maximum gain levels that the user will be limited to The mute function essentially turns the volume off All of these functions can be controlled via the RS 232 port or the control status connector An example would be if you want to control the volume of the speakers you could use two control pins on the control status connector for volume up and volume down Another pin co...

Page 21: ...automatic microphone mixer in conjunction with directional microphones will reduce reverberation and noise the two major culprits in making voice communications difficult to understand In Figure 10 direct audio from a person s voice is picked up by several microphones connected to a microphone mixer that has all microphones on at all times Direct and reflected audio reverberation is picked up by a...

Page 22: ...by reducing overall multiple microphone pickup of reverberation and noise Unlike most automixers the XAP 800 implements its mixing function completely in the digital domain This greatly increases precision in making automixing decisions All audio is routed through the XAP 800 both microphone and speaker audio which means the XAP 800 can more accurately make microphone activation decisions For exam...

Page 23: ... separate automatic mixers working independently within a single unit and up to four independent global mixers across multiple units In addition more microphone channels can be added by linking XAP 800 units via the Expansion Bus the digital network bus Unlike other expandable automatic microphone mixers the XAP 800 works as a single unit for up to eight units networked together for a total of 64 ...

Page 24: ...s feature increases the audio level required to gate on additional microphones after the first mic gates on This helps ensure that only one mic gates on when a person speaks Last Mic On Mic1 8 Off Last Mic On leaves the last activated mic on until a new one is activated Mic 1 8 mode reverts back to the mic you ve selected for Mic 1 8 On when all other mics gate off These features are useful to ens...

Page 25: ...hone Off Ambient Level Gate Ratio Microphone turns on when microphone level goes above the Gate Ratio Time Level Level Figure 13 XAP 800 Automixing Gate Functions Automatic microphone mixing is a key part of the XAP 800 solution set Because all decisions regarding automixing are made by the same digital engine better decisions in automixing can be made ...

Page 26: ...he audio level required to First Mic Priority Mode Mixer wide On Off gate on additional microphones after the first mic is gated on Keeps the last gated microphone or Last Mic Mode System wide Last Mic 1 8 Off one Mic 1 8 on when no mics are pro viding a gating input Specifies how much louder above the Gate Ratio Adjust Input 0 to 50dB ambient level the audio level must be channel 1 8 to gate on O...

Page 27: ... for mic or line level appear on the rear terminal block Both gated and non gated inputs are provided on the matrix for delivery to desired destinations This is provided because in some applications such as a courtroom direct non gated outputs are required Default routing for gated microphone inputs are to the O Bus Non gated outputs are routed by default to their corresponding output number i e i...

Page 28: ...liary mix buses They are used to route auxiliary audio such as from an APV200 IP video codec XAP TH1 telephone interface between units on the network These buses are used as mic mix buses when NOM count is not required PA Adapt Expansion Bus Reference Buses The Expansion Bus reference buses provide a system wide bus for mic channels to receive a reference input for PA Adaptive Mode and acoustic ec...

Page 29: ...1 0 O u t p u t 1 1 O u t p u t 1 2 I n p u t s 1 8 t o o t h e r u n i t s I n p u t s 9 1 2 t o o t h e r u n i t s XAP 800 Default Routing Diagram Outputs To Processing To Expansion Bus Routing Matrix Setup 1 2 3 4 5 6 7 8 9 10 11 12 O P Q R S T U V W X Y Z A B C D E F G H Input 1 N G Input 2 N G Input 3 N G Input 4 N G Input 5 N G Input 6 N G Input 7 N G Input 8 N G Input 9 X X X X Input 10 X ...

Page 30: ... 10 11 12 Program Parameter Selection Range Output Gain Adjust 60dB to 20 dB 0 Mute On Off NOM On or Off A B C D E F G H Program Parameter Selection Range Processing Filters 1 15 See Processing Filters Worksheets Delay 0 500ms 0ms 02ms steps Compressor On Off Threshold 30dB to 20dB 0dB Ratio 1 1 1 20 Attack Time 0 5ms to 100ms in 0 5ms steps 1ms Release Time 5ms to 2sec Increment of 5ms 1s Process...

Page 31: ... to favor the instructor s microphone to facilitate effective dialogue in the room When a particular microphone gates on nearby speakers can be attenuated or muted to reduce feedback Also participant microphones can be set to gate off when secondary audio sources are in use The left and right speakers at the front of the room can be configured to provide stereo sound from a stereo secondary audio ...

Page 32: ...3 70V Control Panel optional CD VCR VCR PA870 APV200 IP Videoconferencing Codec Esc sc En Enter er Met eter er 12 12 8 8 8 8 4 4 4 4 0 4 4 4 4 10 10 10 10 30 30 30 30 1 2 3 4 5 6 7 8 Mic On ic On 0 AP 8 0 Transmit ansmit Rec eceiv eive On On Off ff H AP T 1 XAP TH1 Telephone Interface Lapel Mic Mic 1 Ceiling Speakers Zone 1 White Board Screen Left Speaker Right Speaker Video Projector Desk Desk De...

Page 33: ...d Then say the divider between Rooms A and B is removed for a combined meeting You can use a preset that gates off microphones 3 and 4 while the audio from microphones 1 and 2 are routed to all speakers in Rooms A and B while retaining the settings for the ongoing meetings in Rooms C and D Later when all partitions are removed for a final group meeting you can use a preset that gates on only micro...

Page 34: ...ntion Center Installation basic example Mics Room A Room B Room C Room D Control Panels optional VCR VCR PA870 Esc sc En Enter er Met eter er 12 12 8 8 8 8 4 4 4 4 0 4 4 4 4 10 10 10 10 30 30 30 30 1 2 3 4 5 6 7 8 Mic On ic On 0 AP 8 0 Transmit ansmit Rec eceiv eive On On Off ff H AP T 1 XAP TH1 T elephone Interface APV200 IP Videoconferencing Codec RS 232 Control Figure 21 Hotel Convention Center...

Page 35: ...line to be heard clearly throughout the courtroom This is an ideal addition to the system because it allows people to appear in the court telephonically reducing travel expenses and wasted time The APV200 IP Video Codec integrates perfectly into the XAP 800 conferencing system This allows you to videoconference between courtrooms and jails to reduce transport costs and maintain security During cou...

Page 36: ... Chamber Judge Clerk Witness Defense Jury Plaintiff Gallery Evidence Esc Esc Enter Enter Meter Meter 12 12 8 8 8 8 4 4 4 4 0 4 4 4 4 10 10 10 10 30 30 30 30 1 2 3 4 5 6 7 8 Mic On Mic On 0 AP 8 0 XAP 800 Control Panel optional APV200 IP Videoconferencing Codec Transmit Transmit Receive Receive On On Off Off H AP T 1 XAP TH1 Telephone Interface Figure 23 Courtroom Installation ...

Page 37: ... the front left and right speakers which directs participants attention to the person speaking on the video screen Program audio and other mic audio is routed to the ceiling speakers for a natural sounding conference Whenever a given mic in the room gates on audio to that participant s speaker would gate off to prevent feedback and the volume level of the microphone to adjacent speakers might be r...

Page 38: ... 800 Boardroom Installation basic example Ceiling Speakers Spkr 1 Spkr 2 Spkr 4 Spkr 5 Spkr 6 Spkr 7 Spkr 3 CD PA870 PA870 Esc sc En Enter er Met eter er 12 12 8 8 8 8 4 4 4 4 0 4 4 4 4 10 10 10 10 30 30 30 30 1 2 3 4 5 6 7 8 Mic On ic On 0 AP 8 0 APV200 IP Videoconferencing Codec Transmit ansmit Rec eceiv eive On On Off ff H AP T 1 XAP TH1 T elephone Interface Left Speaker Right Speaker Figure 25...

Page 39: ... application Complete instructions for using G Ware are provided in the XAP 800 Installation and Operation Manual Begin by selecting the Configuration matrix in G Ware The Configuration matrix in the figure below illustrates how the crosspoints in the matrix would be set for this application Notice the cross point level control Also notice the equipment assigned to the inputs and outputs these cor...

Page 40: ... Figure 27 below Figure 27 Inputs 1 8 Window In this example notice that the minimum and maximum gain limiters yellow and green arrows on the Fine gain adjustment are set to 10dB and 20dB This keeps the audio within a specified gain range to eliminate problems associated with gain level extremes Click the AEC button on the Mic 1 input This opens the Acoustic Echo Canceller window see Figure 28 ...

Page 41: ...n immediate proximity to each other and are used exclusively by the same participant This is why Speaker 1 is selected as the acoustic echo canceller reference point for Mic 1 The AEC reference point for Mic 2 would be Speaker 2 This reference pattern continues as you configure the remaining mic inputs Click Close to return to the Inputs 1 8 window The NC button opens the Noise Canceller window se...

Page 42: ...his case to ensure that all mics share this gate information with each other This ensures proper gating interaction between all mics in the room Click Close to return to the Configuration matrix Note that in the Configuration matrix Figure 26 page 38 the CD player inputs are routed through the processing channels This allows for additional processing and control of the CD player audio Click the Fr...

Page 43: ...D channels to operate in unison Close this window then click Filters in EQ CD Left to open the Processing Filters window see Figure 33 In this scenario high shelving and low shelving filters are established for the left CD channel to enhance audio response The same filters would be established for the right CD channel The high shelving filter has a frequency of 3kHz and gain of 3dB The low shelvin...

Page 44: ...nel This section discusses direct remote control There are two functions available control and status see Figure 34 To activate a control function pins on the control status connectors labeled A and B must go low either in a momentary or sustained action depending on the setup of the unit A status pin shows the status of a particular parameter Status outputs sink at a maximum of 40mA of current th...

Page 45: ...s include volume up volume down mute etc In addition pins can be programmed to call up to 32 preprogrammed presets each preset representing a programmed configuration Thus routing level control AGC equalization etc can instantly be changed or reconfigured by presets An example of a useful preset would be in room combining where the room configuration needs to change on the fly Wall buttons can be ...

Page 46: ...tput mute 13 Yes C M Not programmed 14 Yes S Volume up D output 1 1dB 15 Yes C M Not programmed 16 Yes S Volume down D output 1 1dB 17 No S Mic 1 Gate Status 18 No S Mic 2 Gate Status 19 No S Mic 3 Gate Status 20 No S Mic 4 Gate Status 21 No S Mic 5 Gate Status 22 No S Mic 6 Gate Status 23 No S Mic 7 Gate Status 24 No S Mic 8 Gate Status 25 No Ground Ground 1 No C L Preset select bit 0 2 No S Stat...

Page 47: ...as the preset using the software Also program any status outputs 6 Connect the user panel s and verify that direct control status is operational 7 Now install the audio system and complete the audio calibration procedure through the PC software Test tones test noise and all gains and actual levels in dBu are provided Macro Pro Scripting Language Macro Pro scripting language included with the XAP 8...

Page 48: ...ol and status Mic line input select and phantom power on off control and status Microphone gate activation status Control and status of AGC and equalization Routing Automixing functions and modes Control Status connector configurations Preset macro configurations Password protection Expansion Bus setup System setup The RS 232 serial port was generally intended to be used as follows 1 Set up and pr...

Page 49: ...oss all expanded units The most common mode that is expanded is NOM number of open microphones Unlike these devices G Ware software makes all functions available to expanded units making a linked XAP 800 system capable of automixing 64 microphones and 32 line inputs G Ware takes advantage of a DSP infrastructure to accomplish this task It uses the Expansion Bus a high speed network protocol to all...

Page 50: ...panel LED VU meter In addition numeric audio levels are displayed on the LCD panel Menu Structure System This menu is used to access presets 1 32 and set security parameters and the master slave configuration Also the System menu is used for viewing the device ID number unit ID number and software version information RS 232 This menu is used to configure baud rate and flow control through the RS 2...

Page 51: ...on Bus cables are available Serial RS 232 The serial RS 232 communications port is connected via a standard DB9 connector The RS 232 baud rate can be programmed for 9 600 19 2K 38 4K or 57 6K baud rate Flow control can be set for either hardware or none Pass Codes To prevent unwanted access via the front panel or modem the unit can be programmed to require an access code The RS 232 password is set...

Page 52: ...ng All functions of the XAP 800 are available across a system of linked XAP 800 units which allows automixing of up to eight XAP 800 units 64 microphones and 32 line inputs The XAP 800 takes advantage of its DSP infrastructure in accomplishing this task Networked XAP 800 units communicate to one another via the Expansion Bus see Figure 36 Control status and addressing functions are performed via t...

Page 53: ...e these buses are identical to buses S Z S Z Buses These eight buses are defaulted as auxiliary mix buses They are used to route auxiliary audio such as from a CD player telephone interface or video codec to and from other units on the network These buses are also used as mic mix buses when NOM count is not required PA Adapt AEC Reference Buses These buses provide a system wide bus for input chann...

Page 54: ...oise to provide pure sound The XAP TH1 connects to the XAP 800 via the RS 232 port on each unit A XAP 800 XAP TH1 system can also be controlled with a remote controller such as a Panja AMX or Crestron The diagram below illustrates a typical conferencing system using the XAP 800 and XAP TH1 XAP TH1 Telephone Interface XAP TH1 TELEPHONE INTERFACE TELECONFERENCING 53 Microphones XAP 800 Typical Insta...

Page 55: ...rminal block 0dBu nominal adjustable balanced bridging Impedance 20kOhms LINE OUTPUTS Connector Removable terminal block 0dBm nominal level adjustable balanced Impedance 50 Ohms OTHER CONNECTORS RS 232 DB9 female DCE 9 600 19 200 38 400 57 600 baud Control Status A DB25 female Inputs A active low pull to ground Appendices Appendix A Specifications Outputs A Open collector 20V max 40mA each Control...

Page 56: ... AGC Automatically increases or decreases audio gain to maintain a consistent audio level Automatic Gating Automatically gates microphones on or off based on input levels and other parameters programmed into the XAP 800 Bandwidth The difference between the lower and upper 3dB endpoints of an audio band Also the range or differences between the limiting frequencies of a continuous frequency band Ba...

Page 57: ... and is the de facto standard for professional audio active crossovers Decay Rate slow medium fast Programs how quickly the audio level is attenuated once a channel has been gated off DSP Digital signal processor Echo Canceller Reference The output or Expansion Bus reference the echo canceller uses to remove echo Expansion Bus Consists of two RJ 45 connectors on the rear panel of the XAP 800 An Ex...

Page 58: ...mal input gain setting is one which is adjusted as high as possible above the noise floor without introducing clipping Gate Ratio Specifies how much louder the microphone audio level must be above the ambient sound level before a microphone gates on GPIO general purpose input output The Control Status Port A on the rear of the XAP 800 unit G Ware Software The XAP 800 s setup and configuration soft...

Page 59: ...ecognizes how much loudspeaker audio is picked up by the microphones and then uses this level as the new ambient level when audio is present at the power amplifier This prevents loudspeaker audio from gating ON a microphone while still allowing people in the room to gate ON microphones as they speak PA Adaptive Reference This G Ware setting determines which output typically for a loudspeaker is us...

Page 60: ...y compression is released after the input signal drops below the threshold Reverberation Reflections of sound waves in a room or other acoustical venue Serial Command A bit description designed to execute an instruction or command Signal Delay Used for acoustically aligning speakers in an audio system to provide balanced sound throughout the room Signal Generator A device for generating a referenc...

Page 61: ...ksheet s to define a PA Adapt reference to a local output on this unit E4 Define PA Adapt AEC Expansion Bus References Reference Define as Output 1 12 On Unit Device ID 0 7 Gentner XAP 800 Program Parameter Selection Range Timeout 0 15 5 Mixer Mode Lock Front Panel Set Passcode Date On Off On Off Internal Unit Mixer Groups Device ID No Unit ID No Mixer Group Parameters 0 7 Factory Programmed Progr...

Page 62: ...up Select Internal 1 4 or Global A D A See System Parameters to define Mixers Output Channel 1 2 3 4 5 6 7 8 9 10 11 12 Program Parameter Selection Range Output Gain Adjust 60dB to 20 dB 0 Mute On Off NOM On or Off A B C D E F G H Program Parameter Selection Range Processing Filters 1 15 See Processing Filters Worksheets Delay 0 500ms 0ms 02ms steps Compressor On Off Threshold 30dB to 20dB 0dB Rat...

Page 63: ...nly Filter Sub Type LP HP See Key Processing channels can select from all available filters 6 Filter Type Abrev See Key Center or Knee Frequency Hz Gain Slope dB or dB Octave Bandwidth Octaves Filter Sub Type LP HP See Key 7 Filter Type Abrev See Key Center or Knee Frequency Hz Gain Slope dB or dB Octave Bandwidth Octaves Filter Sub Type LP HP See Key Key Filter Type Frequency Parametric EQ PEQ 20...

Page 64: ...rev See Key Center or Knee Frequency Hz Gain Slope dB or dB Octave Bandwidth Octaves Filter Sub Type LP HP See Key 12 Filter Type Abrev See Key Center or Knee Frequency Hz Gain Slope dB or dB Octave Bandwidth Octaves Filter Sub Type LP HP See Key 13 Filter Type Abrev See Key Center or Knee Frequency Hz Gain Slope dB or dB Octave Bandwidth Octaves Filter Sub Type LP HP See Key 14 Filter Type Abrev ...

Page 65: ...13 15 17 19 1 3 5 7 9 11 13 15 17 19 1 3 5 7 9 11 13 15 17 19 1 3 5 7 9 11 13 15 17 19 Key Room Configuration Setup Each configuration is recalled by activating its listed presets XAP 800 Room Preset Configuration Worksheet Room Configuration No Name and Description H Pin Active High State Preset Command List Configuration s Presets DB 25 Port B Pin DB 25 Remote Control Port B Setup X Pin state is...

Page 66: ...etup Description Description Description Description Description For extra large macros continue commands in next column Macro Name Command List Command List Command List Command List Command List XAP 800 Macro Worksheet Macro Name Macro Name Macro Name Macro Name XAP 800 Macro Worksheet ...

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