jitter reduction?

Chris,

The authors found experimentaly through listening tests that pure tones made it easier to detect jitter. They looked at all frequencies not just 20 Khz. The paper is a mix of mathematical modelling and lab measurments and lab listeting tests. Jitter creates sideband intermodulation distortion - new frequencies appear as the jitter frequencies modulate the musical or primary signal. According to the paper, the best way to hear distortion is to get the sideband distortion in the ears sensitive 1 to 4 Khz range whilst keeping the music outside this range so there is as little masking as possible.

I'd strongly recommend to download and read it if you are interested - refreshingly absent of any formulas and complex mathematical jargon that you often see in AES papers. 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)

The important thing to walk away with is that it still recommends that you should always keep jitter as low as possible as distortion is cumulative...what might not be audible distortion from one root cause can accumulate with other non-linearities to become audible.

Shadorne, thanks.
c

"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.

I don't doubt that a ribbon would likely make jitter distortion all the more audible. I am just surprised that a ribbon would be regarded as a reference source for listening for jitter distortion. Dome tweeters in general have much lower distortion. Given distortion is cumulative would it not be better to use a dome tweeter?

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.