Why USB to SPDIF and not optical?

Correction - not mapping through the device does not disable my devices, it just does not seem to stop the upsampling. The "do not use audio functions" option is the one that disables the devices. Sorry - I got the 2 options mixed up.

"If there is no additional software other than the native drivers, I would suspect that the upconversion still happens. Do you concur? Does your converter get 44.1 out of iTunes?"

No, not with Vista and my converter. It changes 16/44.1 into 24/44.1, so Vista is bit-perfect.

With XP, there is something changed if you dont use Kernel Streaming, but it is not necessarily 44.1 to 48. I believe there is volume adjustment DSP, just like Vista does with 16-bit data.

I dont recommend using iTunes on any PC with any device, even WiFi. Use Mac with iTunes.

Have you tried Jriver?

Steve N.
Empirical Audio

I just installed J River Media Center 13 last night and am still getting 48 MHz output on XP. I installed ASIO4ALL and upconversion still happens. I still need to do some experimenting to be sure I have everything set up correctly. Do you get 16/44.1 out of J River? If I read your comment correctly Vista converts 16/44.1 to 24/44.1, so I would not call that bit-perfect. Is your software adding the bits or is Vista? The purist in me would still like to get the original 16/44.1 out to my DAC without the any changes happening in the PC. I sometimes feel like I am losing the battle with this. Might try foobar next, but I am not sure I can live with the interface. Thanks for your help.

"Do you get 16/44.1 out of J River?"

Yes, but with my USB converter it's 24/44.1. With some devices attached to my Pace-Car, it's 16/44.1. The Sonos is also 24/44.1, but bit-perfect.

"If I read your comment correctly Vista converts 16/44.1 to 24/44.1, so I would not call that bit-perfect."

Vista and XP both change 16/44.1 into 24/44.1 with my USB converters. It's bit-perfect. The data is not modified. The noise floor is just lowered.

"Is your software adding the bits or is Vista?"

Both, its the firmware of the USB interface talking to Windows audio stack S/W in XP and Vista.

I think your problem is iTunes. If you use Jriver or Foobar and either unmap or use Kernel Streaming with XP, you will be bit-perfect. The sound quality will be a lot better too. I recommend Foobar 0.8.3.

Steve N.
Empirical Audio

Hey dtc.

"The purist in me would still like to get the original 16/44.1 out to my DAC without the any changes happening in the PC."

Why do you prefer 16/44.1 over the higher resolutions? I am under the impression that 16 bits is better than 24 and 48kHz is better that 44.1 and 96 is better than 48, etc...
Am I missing something?

Hey Steve.

Why is Kernel Streaming better than ASIO for KMixer avoidance?