Noob Alert!! What does jitter sound like? - Page 3

A lot of dacs have a generic USB input, it is widely reported that a generic USB output to a dac is of high jitter, hence there are reports from users of USB dacs that also have an SPDIF input, that the SPDIF input is of better sound quality than the USB. This is the methodology that demonstrated to me the obvious effects of jitter, providing the USB and SPDIF is bit-perfect, the likely variable is the degree of jitter present in the digital signal. I could be wrong.

Try putting a nice reclocker into a digital front end, and see if it makes a difference. This test can really be performed a number of ways. Use your imagination.

When it comes to digital sources, jitter is the ONLY difference. Data and offset errors are rare, particularly when the track is ripped using Accurate-Rip.

Steve N.
Empirical Audio

Steve N.

There are many different types of jitter, If you are refering to pereodic jitter then you cannot hear it, as it is a hardware issue within the timing signal of your systems. What you can hear though are the negative affects it has on the audio sugnal such as distortion. There are many great sources of information out there.

That suggests USB is more prone to jitter than SPDIF. Is that correct? There are also reports that different USB cables sound different. That is not my expereience.

No.

USB can be just as low or lower in jitter compared to the best CD transports or Firewire interfaces. It is a function of the clock used and the USB implementation. Even my older Adaptive mode USB interface in my Off-Ramp 3 was found to be "the best" in the Feb issue of TAS and also in the Positive-Feedback USB converter shootout. My newer USB interfaces are even better.

There are lots of USB interfaces based on the plug-and-play TI chips. There is only so much you can do about the jitter of these chips IME and as a result they have given USB a bad name in some circles. They can be fairly good with an expensive clock, but dont approach what is possible with other USB implementations.

Approaches that use Adaptive CEntrance firmware or Asynchronous firmware can both be excellent, depending on implementation.

Steve N.
Empirical Audio

Steve N, you have posted some great information and I had a look at the Empirical Audio site which is great.

But what do you say jitter actually sounds like? Or is it a contributing factor in making over all sound quality?

Like my earlier post (white-paper) says, it is like looking through a dirty window. Lack of clarity and focus. Lack of contrast. Sometimes even halos around the performers. Depth and width of image is compromised.

Steve N.

Yes, but while you're learning of the problems created by jitter, bear in mind that the teacher makes his living selling devices to remove the jitter. It's kind of like taking entomology classes from the Terminix man. There may be some valuable information there, but it isn't likely to be nearly as valuable as keeping the context, and the conflicts, in mind at all times.

P

Nobody can hear jitter. It's not audible. Any time someone talks about it, it gets into very technical discussions until it's not about the music anymore.

Random Bump?

It sounds like random harmonic distortion in the time domain...easy to hear when reclocking toslink to coax on the Firestone Bravo reclocker: the sound is clearer/more focused and less colored. There's no going back, really.

Edited by leeperry - 4/24/11 at 4:48am

Jitter itself has no sound as it is timing error...  it affects your audio in negative ways though causing distortion and artifacts..etc.

The importance of jitter nowdays is over rated significantly. With the old & not to mention all of the cheap CD players had tremendous jitter. This combined with the old ladder type DACs were notorious for bad sound. Older ladder type DACs, especially the cheap ones were really bad with poor low level linearity as well as using clocks with huge jitter was very common back then. There were good ladder type DACs back then as well as low jitter clocks but most consummer gear didn't get them so we had to suffer with poor sound for years. The one bit DACs were the savior for the masses due to much better low level linearity + they were more immune to input level jitter than ladder type DACs as the actual sample rate was boosted to a much higher frequency. This conversion proccess essentially eliminates the effect of input jitter on the output as the ouput signall is not of the same frequency of the input & has its own clock.

 

It would be difficult at best to evauat jitters effect on sound with any current 1-bit or older ladder type DACs. In older ladder type DACs the poor linearity would dominate the sound even in the case of really bad jitter.whereas the 1-bit DACs are largly uneffected by input jitter. Only native jitter from the internal clock of the CD player or computer soundcard matter now & those have much improved over the years. Creating intentionally jittered test files is meaningless with modern 1 bit DACs as these would ignore the input jitter anyway. You would still be measuring the content of jitter from the system clock & not anything to speak of from the input jitter