CAS 8: iTunes PC Bit Transparent @ High Resolution

December 31st, 2009 Leave a comment Go to comments

I wrote an article earlier regarding the bit transparent playback issue with PC (http://www.designwsound.com/dwsblog/?page_id=1607)

The article was incorrect, there is setting which makes PC iTunes bit perfect software even in high resolution playback. iTunes is based on QuickTime, and there is Quicktime – > Edit – > QT Preference – > Audio -> Audio Output.



You will need to match this output to your playback files. For example if you want to playback playback 24/96kHz, you will need to select 24bit/96kHz on this preference. **iTunes 9 adds support on WASAPI driver. This allows itunes by pass the k-mixer that may affect the bit transparency output. WASAPI was invented since Windows Vista, so if you are using Windows XP, you will see the same situation as below that the WASAPI option is grey out.

UPDATE: DEC2009 – I have tried on the new Windows 7 with iTunes 9 and WASAPI, but the iTunes does not automatically change sampling rates according to the file native rate.



I have done the same bit transparent test and the result is once the QT preference setting matches with the iTunes playback resolution and sampling rate, the audio output is bit transparent. I have also tested using 24bit/192kHz setting to playback 24/96kHz files, the output is not bit transparent.




At least this is a good news that PC iTunes works the same as MAC version and allows bit transparent playback.


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  1. Robert Chen
    January 13th, 2010 at 09:05 | #1

    Do I need to install WASAPI if I am using Weiss Minerva through firewire?

  2. March 4th, 2010 at 12:28 | #2

    Hi Robert, the WASAPI is depends on the program, and not the hardware. sorry for late reply.

  3. Jim
    August 21st, 2010 at 15:26 | #3

    Hi, I am using iTunes 9 with Windows 7 and Weiss Dac202. I have followed your instrunctions to get but transparent output (WASAPI and proper output format selected on quicktime; volume set to max, eq and DSP features off on iTunes) but, still, I do not pass the bit transparency check implemented in Dac202 (I get a flashing fail / 16bit indication when testing with the 16bit/44.1kHz file and simply fail when testing with higher resolution files).

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