Better converting usb or spdif?

[Sandor]

I have in hands a linux box equipped with both USB and spdif digital audio outputs.
I want to send digital audio stream to the I2S inputs of a dac chip.
Will I obtain better results converting usb with a good device, such as those based on xmos, or converting spdif with a good receiver, such as wm8804?

[erin]

If done well, both will give good results.

I have no proof, but my feeling is that usb is better.

[wwenze]

I don't trust USB audio controllers. And the USB interface is too shaky compared to the Direct Media Interface which connects the Northbridge to the Southbridge where the integrated audio controller is located. (Read as: stuttering and pops with USB DACs)

SPDIF is in many ways technically inferior to USB, but it only needs to do a single job hence reliable.

Ultimately the end result doesn't really care which interface you use, measurements show that either can be worse than the other. But I hate stuttering.

[abraxalito]

If you need high sample rates I'd go for USB, otherwise stick to SPDIF as the isolation is way simpler (a fairly cheap transformer).

[qusp]

if you get stuttering and pops you are doing something wrong with usb. perhaps too low latency is set, or you do not have your driver set up with priority access to the audio hardware. maybe old computer? USB is done very well is IMO superior to any spdif, but the WM part is good, not so easy to get right though.

[phofman]

Originally Posted by wwenze

I don't trust USB audio controllers. And the USB interface is too shaky compared to the Direct Media Interface which connects the Northbridge to the Southbridge where the integrated audio controller is located.

I am curious what bus the integrated controllers in the southbridge are connected to. They appear as PCI/e devices. According to Basic PC architecture - Page 1 it is an internal PCIe bus. Both intel HDA sound controller and USB controller would be connected to that.

[Sandor]

Originally Posted by abraxalito

If you need high sample rates I'd go for USB, otherwise stick to SPDIF as the isolation is way simpler (a fairly cheap transformer).

Do you consider 96kHZ a high sample rate?

[wwenze]

Originally Posted by qusp

if you get stuttering and pops you are doing something wrong with usb. perhaps too low latency is set, or you do not have your driver set up with priority access to the audio hardware. maybe old computer? USB is done very well is IMO superior to any spdif, but the WM part is good, not so easy to get right though.

About this I need assistance, I failed to find a way to change the latency setting for USB DACs running on Windows' standard drivers. No ASIO driver either.

BTW, i3 CPU, can't be too old.

[abraxalito]

Originally Posted by Sandor

Do you consider 96kHZ a high sample rate?

In this context, no - if that's the highest you're going I'd stay with SPDIF if I were you.

[erin]

Originally Posted by wwenze

About this I need assistance, I failed to find a way to change the latency setting for USB DACs running on Windows' standard drivers. No ASIO driver either.

BTW, i3 CPU, can't be too old.

cMP² | CMP / 07Optimisations

do the things listed on the link above and tell me if the sound gets better.
It does not specifically change the latency setting, but reduces other things running in the background. This should free up processing power to be able to run USB audio without dropouts and clicks and pops.

Also, you really should run ASIO.