DACS: USB VS spdif

[BLASTO]

@Thad,

The DAC's input buffer stage should remove any timing nsconsistensies right? It is will like hearing the music a second or 2 later but with correct timng if buffering is well implemented.. Is my understanding correct?

 

[corElement]

I doubt it extends into seconds, most likely MS.

 

[Thad E Ginathom]

I don't use USB. The two interfaces I have used over the past ten years or so have been PCI, and, more recently, Firewire.

But, in general, does buffering cure all evils? One would hope so, because that is what it is there for --- to smooth out the supply and demand at the cost of higher latency, and, as you suggest, unless doing studio recording stuff, that latency, be it a microsecond or a whole second, really does not matter, except that it might give a feeling of sluggishness when pressing the play button.

Unfortunately, buffering does not cure all ills. One thing is this horrible thing called DPC latency, which I once had to do a lot of reading about, and would now rather forget This can cause anything from crackles and pops to complete dropouts in the sound. In short, it can render a PC useless for audio playback!

I don't think it is that common, but it is not that rare either. Google will tell. Don't ask me to try to explain it: it still hurts too much!

The other form of timing inconsistency in digital audio is jitter and I'm sure that everyone here must have been involved in at least one jitter conversation. Depending on whom you read, it is either the ever-lurking H1N1 influenza of digital sound --- or something that engineers pretty-much designed out years ago.

 

[square_wave]

This involves many factors:

Is your current DAC adaptive or Asynchronous ?If planning to do USB, the dac needs to be Asynchronous. The quality of the implementation is of prime importance. Such DACs are usually a bit expensive. An alternative is to use an outboard USB to SPDIF converter like the audiophelio or M2tech EVO and then use a regular spdif DAC with it.

If you have a DAC which is not designed for performance with USB, then a spdif output from a studio grade card from your PC will sound better.

Spdif out from normal pcs with regular sound cards are a hit and miss. I have tried this out many times and they sound quite terrible.

 

[anm]

I think what is more important than async USB vs spdif is that the music player, pc, or other device, should be a dedicate one, and not a general purpose PC which you also use for your office work while listening to music.
Also, a powered hub between PC and DAC is found helpful in some case. My HRT streamer async usb dac gave me a lot of problems - loud cracking noises when the CTO of HRT suggested me to use a powered USB hub. It became better after that. The powered hub isn't powering on these days though - purchased chroma brand from chroma.

 

[Thad E Ginathom]

There are ideal-world solutions. There are also things that we do because, theoretically, they might make a difference, and hey, it's no sweat. The former includes dedicated audio PCs, the latter includes stuff like putting the interface/DAC outside the case.

PCs are absurdly powerful compared to early days: we barely tickle their processing power. On the other hand, problems such as I alluded to above have only happened to me in recent years! I had less troubles with less powerful machines of a previous generation. Much as I like to be it's hard to be dogmatic.

Probably we are not far from just assuming that a PC of sorts (possibly branded 'media player and not physically resembling what we think of as a computer) will be a taken-for-granted item in the hifi setup, just as the CD player is now, and the Turntable was (for everybody, not just the specialists) a few decades ago. As that happens, the marketing people will adopt it as the new must-have box, and persuade us that we can't actually play music at all on our ordinary PCs. That won't, of course, be true --- when when did that ever bother marketing departments!

 

[corElement]

Spdif out from normal pcs with regular sound cards are a hit and miss. I have tried this out many times and they sound quite terrible.

This.. is what I wanted to hear from someone other than me, thank you. :yahoo:

I just needed to confirm that this is an established fact that the external DAC cannot make up for poor quality spdif.

 

[Thad E Ginathom]

I was told something similar by Genelec engineer Clifford Pereira, and my view is that he is not a guy to fall for stuff because it is fashionable/audiophile/audiophool/whatever.

It's all digital ... but circuits are translating from one protocol to another, and there are circuits and circuits.

PC-built-in S/PDIF to external interface/DAC may well be better than PC-built-in analogue out, though.

PCs contain such a huge variety of components. Many of them are cobbled together at home. Consistent results from one machine to another might be more than we can expect. One person says his built-in digital out is just fine, another says his is rubbish, and probably they are both right.