Is computer audio a bust?

Current DACs have difficulty reducing jitter to inaudible levels because this is a difficult engineering challenge, even for seasoned designers. It always has been. The jitter on S/PDIF inputs on DACs is generally reduced somewhat by the receive chip, which uses a PLL to recover the clock from the datastream, but a low jitter input to this receiver chip is still beneficial. Other DAC designs use resampling chips and circuits to establish a new master clock. These can reduce jitter even more than the receiver chip, but there are two downsides: 1) they inpart their own kind of distortion due to way that the resampling algorithm is implemented 2) the new master clock and associated circuitry/power supply adds its own jitter.

Thes best solution for reducing jitter in a DAC is to put a master clock front-end on the DAC. There are two types of these available now, the Async USB interface and the network renderer. Both of these effectively discard the clock in the source computer or device and generate a NEW master clock.
if the power, circuit design and clock selection is optimized, the jitter can be extremely low with these input circuits.

The thing to understand is that these are not easy to design and its really esy for lots of jitter to creep back into the circuit, even if you u a Femtoclock etc..

also, jitter is never reduced to zero as some manufacturers would have you believe.

Jitter when characterized by a single number, such as RMS jitter is an inadequate measurement. Jitter has a spectral component as well as a distribution of amplitude. these are actually more important than any single number to predict if one jitter is more audible than another.

Steve N.
Empirical Audio

It seems this discussion veers into the overly academic. To my mind computer audio is certainly not a bust, on the contrary it's here to stay and to my ears trumps CD-playback (where same CD is ripped to harrdrive) in a pretty obvious fashion. Not to speak of the advantages of high-res downloads in various forms.

Unless CD-playback has advanced radically these last years, while computer audio had strangely not(i.e.: its implemtations via software and hardware optimizations), even the most basic of PC-setups (laptop - USB - DAC) with very cheap DAC's (~$200) will better CD-players up to and even beyond $2.000 - at least that's my experience.

Moreover: going to lengths trying to bash either USB or S/PDIF as interfaces seems an utter waste of time and completely robbed of any sense of pragmatism. I mean, come on - both interfaces can sound great. Any exclusive investment in one or the other seems to be a limiting and, sorry for putting this bluntly, stupid decision.

10-22-14: Audioengr
What does that tell us? Its obvious to me based on 15 years of listening to systems at trade shows and in salons. Most systems are not resolving enough or low noise and distortion enough to make these differences obvious. I have heard a number of reviewers systems as well. Same thing, unfortunately. Most systems simply have a preamp that creates so much masking and compression that these differences cannot possibly be heard. Good active preamps are like hens teeth.

That is most likely true although I know that Barry Diament did uses the Metrum Halo ULN-8 as a dac/preamp. That's a pretty ruthless unit.

10-22-14: Audioengr
Current DACs have difficulty reducing jitter to inaudible levels because this is a difficult engineering challenge, even for seasoned designers. It always has been. The jitter on S/PDIF inputs on DACs is generally reduced somewhat by the receive chip, which uses a PLL to recover the clock from the datastream, but a low jitter input to this receiver chip is still beneficial. Other DAC designs use resampling chips and circuits to establish a new master clock. These can reduce jitter even more than the receiver chip, but there are two downsides: 1) they inpart their own kind of distortion due to way that the resampling algorithm is implemented 2) the new master clock and associated circuitry/power supply adds its own jitter.

Thes best solution for reducing jitter in a DAC is to put a master clock front-end on the DAC. There are two types of these available now, the Async USB interface and the network renderer. Both of these effectively discard the clock in the source computer or device and generate a NEW master clock.
if the power, circuit design and clock selection is optimized, the jitter can be extremely low with these input circuits.

The thing to understand is that these are not easy to design and its really esy for lots of jitter to creep back into the circuit, even if you u a Femtoclock etc..

also, jitter is never reduced to zero as some manufacturers would have you believe.

Jitter when characterized by a single number, such as RMS jitter is an inadequate measurement. Jitter has a spectral component as well as a distribution of amplitude. these are actually more important than any single number to predict if one jitter is more audible than another.

Interesting. In your opinion, is jitter management or the lack thereof the stumbling block to true analog reproduction? Also, what are your thoughts on grounding and jitter production? I know someone in the industry who says a lot of standard grounding schemes are woefully inadequate.

Finally, do you have any thoughts on the software codeveloped by Vertex/Nordost that supposedly measured system jitter? http://www.stereophile.com/rmaf2010/nordost_and_vertex_measurements/index.html

10-23-14: Phusis
It seems this discussion veers into the overly academic. To my mind computer audio is certainly not a bust, on the contrary it's here to stay and to my ears trumps CD-playback (where same CD is ripped to harrdrive) in a pretty obvious fashion

On the contrary, I know quite a few philes who would argue with you after having done both. I have heard computer fronted systems sound like crap even with whizbang dacs and big money ancillary pieces.