jitter reduction?

I can easily hear the effects of jitter with either dome tweeter or a good ribbon. The point that I was making is that true stereo improves your odds for hearing jitter easily using lots of different source material.

Jitter studies must be taken with grain of salt. The systems and recordings used for these are all inferior IMO. I have been reducing jitter in my own and other products for many years. Each time I think the incremental jitter reduction will be inaudible, I'm surprised to find that it is audible, at least in my system, which has world-class resolution and extension. For instance, an obvious change can be heard between the excellent Superclock4 and the new Ultraclock when used for clocking USB interfaces, CDP's or upsampling DAC's. Both of these have miniscule jitter, on the order of 10-100's of picoseconds.

Most jitter circuits in CDP's and DAC's have limited effect. None of them completly eliminate jitter. This is impossible. Most use either a PLL scheme or asynchronous upsampling (ASRC). The chips that do these inject their own jitter, and usually are not immune to incoming jitter either, although they do recude overall jitter.

The goal should be making it inaudible. Again, if your system has a lot of other sibilance and noise, then you may not hear the benefits of low jitter. It is just one more thing that needs to be addressed when creating a highly resolving sytem.

Here are some more papers to read:
http://www.positive-feedback.com/Issue22/nugent.htm
http://www.positive-feedback.com/Issue14/spdif.htm

Steve N.
Empirical Audio

Gmood1 - I have a Proceed AVP. No problem hearing the effects of jitter on this one. It beats the Lexicon hands down. It's so good that I have not bothered to mod it. I dont listen to music on it anymore, only movies.

As for the crossover, I do mod the DEQX, but it is expensive. In the future, I wil be doing fewer mods, not more. My own products take up most of my time now.

Steve N.

"They used headphones in listening tests so loud speaker distortion was not an issue (most loud speaker distortion would probably make it even harder to hear jitter"

Headphones???

I used to believe that headphones were better than speakers, but not anymore. I have attended headphone shows and tried the best of the best. My ribbons sound better and give more detail and 3-D imaging than the best headphones available. The sibilance from jitter I have found to be more obvious in a system that images properly. Headphones dont image.

It's like trying to identify a flaw in a 2-D photograph versus a 3-D live image. Much easier to pick out the flaw in a 3-D presentation. IME the brain uses its best sensing capability in stereo, both audio and visual.

Steve N.