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Enable 4channel audio output on Maya 44 USB

Posted on 2009-05-18
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Last Modified: 2013-12-08
Hello,

I've got code that plays 4 different waveforms on the 4 outputs of a quadrophonic sound card. It works fine when using the SoundBlaster Audigy card inside my computer, but it fails when using the Maya 44 USB card with which it is intended to work. The output in this case is limited to just 2 channels (front left+front right), the other two (back left, back right) being muted. The code uses DirectX and initializes the buffer using the code below. I tried to look at the mixer of the Maya card, also at the configuration of speakers of it and everything seems to be right - no muting and quadrophonic speakers. How do I enable the other 2 channels, either by code or by clicking somewhere in Windows?

Thanks a lot
// Create buffer
  DSBUFFERDESC dsbd;
  WAVEFORMATPCMEX wfex;
  wfex.Format.wFormatTag = WAVE_FORMAT_EXTENSIBLE;
  wfex.Format.nChannels = 4;
  wfex.Format.nSamplesPerSec = 44100L;
  wfex.Format.nAvgBytesPerSec = 352800L; 
  wfex.Format.nBlockAlign = 8;  /* Same as the usual */
  wfex.Format.wBitsPerSample = 16;
  wfex.Format.cbSize = 22;  /* After this to GUID */
  wfex.Samples.wValidBitsPerSample = 16;  /* All bits have data */
  wfex.dwChannelMask = SPEAKER_FRONT_LEFT | 
                       SPEAKER_FRONT_RIGHT | 
                       SPEAKER_BACK_LEFT |
                       SPEAKER_BACK_RIGHT;
  wfex.SubFormat = KSDATAFORMAT_SUBTYPE_PCM;  // Specify PCM  
 
  dsbd.dwSize = sizeof( dsbd);
  dsbd.dwFlags = DSBCAPS_CTRLVOLUME | DSBCAPS_STICKYFOCUS | DSBCAPS_CTRLPOSITIONNOTIFY;
  // Prepare sound for 200 milliseconds
  // NOTE: We must make sure that the number is always even 
  // because of the way we fill in the buffer
  const int nSamples = wfex.Format.nSamplesPerSec / 5 + (wfex.Format.nSamplesPerSec / 5)  % 2;
  dsbd.dwBufferBytes = nSamples * wfex.Format.nChannels * (wfex.Format.wBitsPerSample / 8);
  dsbd.dwReserved = 0;
  dsbd.lpwfxFormat = &wfex.Format;
  dsbd.guid3DAlgorithm = GUID_NULL;
  if (FAILED(intOutputSound.lpds->CreateSoundBuffer( &dsbd, &intOutputSound.lpBuffer, 0)) || 
      !intOutputSound.lpBuffer) 
      return false;

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Question by:bovlk
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2 Comments
 
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Assisted Solution

by:PCBONEZ
PCBONEZ earned 500 total points
ID: 24502319
You do have all 4 RCA cables connected on the input side,,, yes?
Those wouldn't be there if you could get 4 channels through USB.

My reading suggests the install loads generic drivers that you then have to go in and update to the correct drivers manually.
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Accepted Solution

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bovlk earned 0 total points
ID: 24578761
Yes, I have all 4 channels connected. I solved the problem by using ASIO instead of DirectX meanwhile so I'm not sure whom to award the points.
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