[oneinthepipe]

The Audio Output - Digital Output settings in Audio MIDI Setup appear to automatically revert from 2ch-16bit (my setting) to 2ch-24bit (default setting ?).

Does anyone know a way to maintain the 2ch-16bit setting (without modifying the application)?

[K Shep]

I spent a few minutes monkeying with my iTunes and I don't have an answer.  I am still figuring out how to tag my albums correctly. 

Kirk

[ted_b]

The Audio Output - Digital Output settings in Audio MIDI Setup appear to automatically revert from 2ch-16bit (my setting) to 2ch-24bit (default setting ?).

Does anyone know a way to maintain the 2ch-16bit setting (without modifying the application)?

What application? The Audio Midi takes its direction from the application (or DAC connected via USB or firewire) so something in your app is defaulting to 24 bit.  For my Weiss DAC2, for example, Amarra changes the Audio Midi automatically depending on the sample rate of the song file.  So it can be anywhere from 16/44 to 24/192.

[oneinthepipe]

ted_b:

iITunes (AIFF files on iMac) -> digital optical from iMac's 3.55mm headphone jack -> Inday toslink to coax switcher -> AVA T8 DAC or AVA Insight DAC -> preamp -> amp. 

Audio Midi Setup reverts to 2 channel 24 bit.  If I open Audio Midi Setup after a restart, and select 2 channel 16 bit prior to starting iTunes, the audio output remains at 16 bit but the reverts to 24 bit after the computer restarts, whether or not the digital optical cable is connected to the headphone jack.

[Crimson]

ted_b:

iITunes (AIFF files on iMac) -> digital optical from iMac's 3.55mm headphone jack -> Inday toslink to coax switcher -> AVA T8 DAC or AVA Insight DAC -> preamp -> amp. 

Audio Midi Setup reverts to 2 channel 24 bit.  If I open Audio Midi Setup after a restart, and select 2 channel 16 bit prior to starting iTunes, the audio output remains at 16 bit but the reverts to 24 bit after the computer restarts, whether or not the digital optical cable is connected to the headphone jack.

Audio Midi defaults to 24-bit word length in the absence of an external application or device (dac) instructing it to do otherwise (Core Audio upsamples 16-bit content to 24-bit for the volume control function). In your case, it may have something to do with the toslink-coax converter not allowing proper communication from the dac back to Core Audio.

[oneinthepipe]

Thank you.

OK, I will try a different converter.  I think that I should try to keep with 16 bit if possible.  It isn't that there isn't any music with 24 bit, but I believe the DAC is strictly Red Book and seems to sound better with 16 bit.

[oneinthepipe]

OK, I am a dummy.  I didn't understand Audio Midi.  Apparently if the DAC and/or adapter are not powered, Audio Midi reverts to 24 bit.  With the DAC powered, when I restarted the computer with another adapter, Audio Midi remained at 16  bit.

Thank you for your assistance.