from AudioUnitProperties.h
:
@constant kAUVoiceIOProperty_VoiceProcessingQuality
@discussion Scope: Global
Value Type: UInt32
Access: read/write
DEPRECATED. Sets the quality of the voice processing unit. Quality values
are comprised between 0 (lowest) and 127 (highest).
Any ideas what is the reason for deprecating this and if there's anything new to replace it?