Using OpenAL to output sound to a specific channel to a 7.1 - openal

Question

all.
I have a project where I need to interface with a A/V receiver via an X-Fi sound blaster card. The A/V receiver is connected to a 7.1 speaker system. I would like to know the start to finish way to access each of the 7.1 channels individually so that I can direct aircraft cockpit information in a simulator. I am using OpenAL and am writing this code in C. I have developed some code that I thought should do the trick, but I am getting audio bleed through on the other 6 speakers. Below is a sample of some of the code I have already written. I hope that someone can help me here.
Thanks, Vincent.`{
ALuint NorthWestSource;
ALint PlayStatus;
switch (event)
{
case EVENT_COMMIT:
//Load user selected .wav file into the buffer that is initialized here, "InitBuf".
LoadDotWavFile();
//Generate a source, attach buffer to source, set source position, and play sound.
alGenSources(NumOfSources, &NorthWestSource);
ErrorCheck();
//Attach the buffer that contains the .wav file's data to the source.
alSourcei(NorthWestSource, AL_BUFFER, WavFileDataBuffer);
ErrorCheck();
//Set source's position, velocity, and orientation/direction.
alSourcefv(NorthWestSource, AL_POSITION, SourcePosition);
ErrorCheck();
alSourcefv(NorthWestSource, AL_VELOCITY, SourceVelocity);
ErrorCheck();
alSourcefv(NorthWestSource, AL_DIRECTION, SourceDirectionNorthWest);
ErrorCheck();
alSourcei(NorthWestSource, AL_SOURCE_RELATIVE, AL_TRUE);
ErrorCheck();
alSourcei(NorthWestSource, AL_CONE_INNER_ANGLE, 180);
ErrorCheck();
alSourcei(NorthWestSource, AL_CONE_OUTER_ANGLE, 270);
ErrorCheck();
SetCtrlVal(panelHandle, PANEL_SOURCEISSET, 1);
//Play the user selected file by playing the sources.
alSourcePlay(NorthWestSource);
ErrorCheck();
//Check that the .wav file has finished playing and if so clean things up.
do
{
alGetSourcei(NorthWestSource, AL_SOURCE_STATE, &PlayStatus);
if(PlayStatus != AL_PLAYING)
{
printf("File done playing. \n");
}//End do-while if statement
}
while(PlayStatus == AL_PLAYING);
//Clean things up more before exiting out of this audio projection.
alDeleteSources(NumOfSources, &NorthWestSource);
ErrorCheck();
alDeleteBuffers(NumOfBuffers, &WavFileDataBuffer);
ErrorCheck();
SetCtrlVal(panelHandle, PANEL_SOURCEISSET, 0);
//alDeleteBuffers(NumOfBuffers,
break;
}
return 0;
}`

Answer 1

I am confronted with the same problem. I want to play a tone to either the left or right ear. The only way I have found so far is to produce a stereo buffer (7.1 buffer for you) with the sound, then overwrite the information on the other channel (... other 7 channels for you) with zeros, and then play it back from a source in front of the listener.
This is my workaround. I know that it is clumsy. But I haven't found any better if you want to stay in openAL and to avoid programming using ALSA directly (for Linux) or CoreAudio (for Mac).
To answer your question more directly: No, there does not seem to be a direct way of saying (as I had wished for): "Speaker #3 say 'Hello World'! All other speakers remain silent."
Cheers,
farid