Apple

Currently working on audio units to create a sound system for a game . What i exactly want is

i have to play 3 sounds simultaneously
Should be able to control pitch and volume for each sound individually
then playback this sound combination in mixer accordingly..

Any one have any idea with audio units can guide me in right direction...what structure of AUGRAPH should i follow ?

EDIT:-

After working on this while reading from apple developer library on Audio Units i made a start now m getting runtime errors while setting input stream for 3dmixer unit in ipad(ios). m getting this exception :- exception 'NSInternalInconsistencyException', reason: 'Error setting property format 3d input 0.'

AudioStreamBasicDescription audioFormatnew;
audioFormatnew.mSampleRate          = 44100.00;
audioFormatnew.mFormatID            = kAudioFormatLinearPCM;
audioFormatnew.mFormatFlags     = kAudioFormatFlagsAudioUnitCanonical;
audioFormatnew.mFramesPerPacket =
 1;
audioFormatnew.mChannelsPerFrame    = 2;  // 1 for mono and 2 for stereo
audioFormatnew.mBitsPerChannel      = 16;
audioFormatnew.mBytesPerPacket      = 4;
audioFormatnew.mBytesPerFrame       = 4;


err = AudioUnitSetProperty(mixer3d_1_unit, 
                           kAudioUnitProperty_StreamFormat, 
                           kAudioUnitScope_Input, 
                           0, 
                           &audioFormatnew, 
                           sizeof(audioFormatnew));
NSAssert(err == noErr, @"Error setting property format 3d input 0.");

The mixer3d_1_unit subtype is kAudioUnitSubType_AU3DMixerEmbedded. Can anyone suggest where m doing wrong or provide me with some sample code for 3dmixer unit for IOS specifically.

Thanks