Best Sound Quality1
Acclaimed Audirvana audio engine upgraded
NEW: Direct Mode
Full Memory Play
Complete file loading, decoding, processing (if needed), and conversion to DAC native format are performed offline, before playback. Thus minimizing the computer load in sync with the audio signal, that is the most detrimental to sound quality.
Direct Mode
By bypassing completely CoreAudio, even the low level layers, this gives an ultra streamlined signal path for audio. And in addition to its sound quality improvement by itself, it reenables the Integer Mode that was lost with OS X Lion & Mountain Lion.
Integer Mode
This brings the optimization at the CoreAudio driver level, by removing all the standard Mac OS X audio processing that is implemented for multi-applications processing: mixing buffer, float to native DAC format conversion. And this moves the sound quality further to higher level, especially for the bass response.
64-bit internal processing
By using very high precision for internal processing, much higher than any DAC could do, enables to reduce to the extreme the rounding errors such processing could have introduced, and thus preserve to the maximum the original purity, when a processing (e.g. sample rate conversion) is needed.
iZotope world benchmark Sample Rate Converter
Audirvana Plus uses iZotope 64-bit SRC that has been acclaimed to be the most transparent sample rate conversion algorithm to date.
For more reading
Refer to the paper I wrote for AMR on OS X audio playback: Audirvana: OSX Bit Perfect and Integer Mode



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