# single speaker addressed - multiple speaker playing

**URL:** <https://psychtoolbox.discourse.group/t/single-speaker-addressed-multiple-speaker-playing/1409>\
**Category:** Uncategorized\
**Created:** [April 1, 2011, 2:38pm UTC](https://psychtoolbox.discourse.group/t/single-speaker-addressed-multiple-speaker-playing/1409 "2011-04-01T14:38:55Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Allen\_Ingling](https://avatars.discourse-cdn.com/v4/letter/a/a183cd/32.png) [@Allen\_Ingling](https://psychtoolbox.discourse.group/u/Allen_Ingling)\
**Post date:** [April 1, 2011, 2:38pm UTC](https://psychtoolbox.discourse.group/t/single-speaker-addressed-multiple-speaker-playing/1409/1 "2011-04-01T14:38:55Z")

</div>

Hi all,  
I'm trying to get a multiple speaker setup with precise timing to work. For some reason, when addressing a single speaker the speaker linked to channel 3 produces the sound as well, just with reduced volume.  
I'm using:  
- the 8 analog output channels of the recomended M-Audio DELTA 1010LT with native ASIO drivers and Mario's portaudio\_x86.dll  
- Windows XP SP2  
- Matlab R2008b  
- 2x Ultron soniccube edition 5.1 (using only the two front and the two surround speakers of each system)  
  
The problem occurs even when addressing a channel that is connected to a different speaker-setup than the channel 3 is connected to. So there should be something wrong with the PC output.  
  
my test-code:  
  
InitializePsychSound(1);  
reqlatencyclass = 2;  
freq = 96000;  
pahandle = PsychPortAudio('Open', 34, 1, reqlatencyclass, freq, 8, 64, [], [0, 1, 2, 3, 4, 5, 6, 7]);  
  
loTone = 0.5 \* MakeBeep(200, 2, freq);  
  
% noTone = 0.0 \* MakeBeep(100, 2, freq);  
noTone = zeros(1,(2\*freq+1));  
  
soundArr(:,:,1) = [loTone; noTone; noTone; noTone; noTone; noTone; noTone; noTone];  
soundArr(:,:,2) = [noTone; loTone; noTone; noTone; noTone; noTone; noTone; noTone];  
soundArr(:,:,3) = [noTone; noTone; loTone; noTone; noTone; noTone; noTone; noTone];  
soundArr(:,:,4) = [noTone; noTone; noTone; loTone; noTone; noTone; noTone; noTone];  
soundArr(:,:,5) = [noTone; noTone; noTone; noTone; loTone; noTone; noTone; noTone];  
soundArr(:,:,6) = [noTone; noTone; noTone; noTone; noTone; loTone; noTone; noTone];  
soundArr(:,:,7) = [noTone; noTone; noTone; noTone; noTone; noTone; loTone; noTone];  
soundArr(:,:,8) = [noTone; noTone; noTone; noTone; noTone; noTone; noTone; loTone];  
  
for i = 1:8  
 audMat = soundArr(:,:,i);   
 PsychPortAudio('FillBuffer', pahandle, audMat);  
 speaker = i  
 PsychPortAudio('Start', pahandle, 0, 1);  
 kbwait  
 WaitSecs(.2);  
 PsychPortAudio('Stop', pahandle);  
end  
PsychPortAudio('Close', pahandle);  
  
Does anybody have an Idea of what I am missing?  
Thanks everybody,  
Benjamin