What does Jitter sound like?

[skiltrip]

I've recently been looking into upgrading my converters, so I've heard the word Jitter mentioned a lot.

What exactly is Jitter and what does it sound like?

[@?,*???&?]

Hashy brightness. Unclear imaging. Ken Pohlman describes 4 different scenarios:

1. right samples, right time

2. right samples, wrong time

3. wrong samples, right time

4. wrong samples, wrong time

Sampling frequencies needs to be done very accurately. If the samples are played back in a different time (i.e. slightly faster or slower rate-wise), then the frequency content of the program suffers which results in hashy brightness. Because of Nyquist theorem, high frequencies are sampled much less than lower frequencies.

The moment of the A to D conversion needs to be done most accurately as it will be the goal to exactly reproduce that sample rate throughout the project or suffer lost (or changed) frequency content.

[apropos of nothing]

What exactly is Jitter and what does it sound like?

Cash registers.

[RefD]

i've got bits that jingle jangle jingle.

[rwc]

question for those more knowledgeable. probably retarded.

Would it be important to mix with the same clock as you recorded on to avoid jitter?

[Scodiddly]

question for those more knowledgeable. probably retarded.

Would it be important to mix with the same clock as you recorded on to avoid jitter?

No - the clock really only matters while you're doing A/D conversion.

Jitter is definitely a weird thing - in the live sound world there's a bit of a debate over externally clocking digital consoles for better sound. I fall on the side of "it doesn't help", because the actual sampling clock has to run many times faster than incoming word clock. I'd even hazard that like bad vs. good types of distortion, there may be types of jitter that some people like.

[@?,*???&?]

question for those more knowledgeable. probably retarded.

Would it be important to mix with the same clock as you recorded on to avoid jitter?

Yes or else you are changing the frequency content of your master material. There is a strong argument to be made for maintaining EXACTLY THE SAME clock source throughout the course of a project- right down to mastering.

Unfortunately, once it becomes a manufactured piece, the D to A clock is whatever the consumer has whether it be CD Player, In-dash car stereo, etc.

[@?,*???&?]

Jitter is definitely a weird thing - in the live sound world there's a bit of a debate over externally clocking digital consoles for better sound. I fall on the side of "it doesn't help", because the actual sampling clock has to run many times faster than incoming word clock. I'd even hazard that like bad vs. good types of distortion, there may be types of jitter that some people like.

Gosh, that sounds just like an audio concern- why is live sound different than studio work? Because no one gives a shit what live sound sounds like? It comes and gos and no one cares.

Anyhow, it's bad theory. Good clocks are essential and jitter is real.

[Scodiddly]

Anyhow, it's bad theory. Good clocks are essential and jitter is real.

Ah, but how exactly does clocking from an internal clock work vs. an external clock? Bob Katz wrote up some stuff on this. Basically when you use an external clock it doesn't just go right to the A/D converter, it has to go through some of the same processing that the internal clock goes through. One item in particular, a "phase locked loop" is there to get everything lined up with the incoming pulse. And a PLL is actually harder to implement properly than a decent clock, which means that the external clock is probably going to have the exact same effect on jitter than the internal clock.

Which is not to say that people don't perceive differences... but real actual double-blind A/B tests are surprisingly hard to come by, versus the usual "it's expensive, and of course I hear the difference!!!" half-assed A/B tests people talk about.

[Scodiddly]

question for those more knowledgeable. probably retarded.

Would it be important to mix with the same clock as you recorded on to avoid jitter?

Yes or else you are changing the frequency content of your master material. There is a strong argument to be made for maintaining EXACTLY THE SAME clock source throughout the course of a project- right down to mastering.

Jitter only occurs when you convert A/D and eventually when you go D/A. If you're mixing in the box, it's all math and the clock source doesn't matter. Maybe the clock source might matter for your in-studio monitoring, but the 99% part of clocking is on input.

[Veej007]

it's like autechre, but for your eyes.

/whoosh (I predict)
//sorry

[@?,*???&?]

Jitter only occurs when you convert A/D and eventually when you go D/A. If you're mixing in the box, it's all math and the clock source doesn't matter. Maybe the clock source might matter for your in-studio monitoring, but the 99% part of clocking is on input.

Whenever you record or playback audio it has to be clocked. Audio is buffered on input and buffered on output. It has to be clocked before being buffered on input and after being buffered on output.

Indeed, using a different clock source can change the sound of what we record and what we playback.

[ctmsound]

question for those more knowledgeable. probably retarded.

Would it be important to mix with the same clock as you recorded on to avoid jitter?

No - the clock really only matters while you're doing A/D conversion.

What about in my situation, where I go D/A out and mix on an analog console? Wouldn't a clock be essential.

[@?,*???&?]

question for those more knowledgeable. probably retarded.

Would it be important to mix with the same clock as you recorded on to avoid jitter?

No - the clock really only matters while you're doing A/D conversion.

What about in my situation, where I go D/A out and mix on an analog console? Wouldn't a clock be essential.

Yes. That's what my original Ken Pohlmann statement was about.

Scodiddly's answer was naff. Bad info.

[Electricide]

http://www.digido.com/bob-katz/jitter.html