The sonic signature of jitter and how to conquer it????

Geardaddy · « **on:** 6 Mar 2008, 12:50 am »

I have been intrigued for some time now as to the real world influence of "jitter" on digital playback. From what I have read, there does not appear to be any consensus on jitter's exact influence and how to effectively deal with it. Many proponents of music servers claim that their systems are superior to CDPs in part due to newer anti-jitter capabilities. Robert Harley's review of the Esoteric G-0Rb atomic clock in TAS this month is interesting and generated a thread or two on the Gon (http://forum.audiogon.com/cgi-bin/fr.pl?ddgtl&1203194310&openfrom&1&4#1). Depending on where technology takes us, we may not have to shed our CD players quite yet and all buy Nova Physics Memory players, etc. Maybe all that is necessary is to slave a CDP to a DAC or clock device as LessLoss (DAC manufacturer from Europe) suggests. They claim superior sonics to any HD-driven system. Anyway, the questions I have are 1) what does jitter sound like to you? and 2) what remedies do you suggest? I will leave you with a quote from Harley's discussion in which he attempts to provide a sonic word picture of jitter:

"loss of space & depth; softening of the bass; hardening of timbre; a glassy sound on initial transients (most noticeably on the leading edge of upper-register piano attacks); a metallic sheen overlaying the treble; and an overall flattening of the soundstage & homogenization of instrumental images with the stage." ""

Rx8man · « **Reply #1 on:** 6 Mar 2008, 01:38 am »

Great post Geardaddy !

Many discussions of getting rid of jitter have been discussed over the decade.

I was ready to jump on the PC band wagon, but there seems to always be a better way to do it, so many options, I can't find a direction.

No way I'm spending 5K on an external atomic clock when in the next couple years it'll be integrated in a $500 player (if it hasn't already)

I'm thinking of sending my transport to a reputable designer (not a part swapper) and have him replace or rework the power supply around the existing clock.

I'd like hearing more feedback on this thread as well.

Ethan Winer · « **Reply #2 on:** 6 Mar 2008, 02:48 pm »

Quote from: Geardaddy on 6 Mar 2008, 12:50 am

what does jitter sound like to you?

Jitter is inaudible because it is typically 120 dB or more below the music, and 20 to 30 dB below the noise floor of a standard CD, which is typically inaudible too. I have no idea why people obsess about stuff like jitter and dither, but of all the things that matter in an audio system - frequency response, distortion, room acoustics, etc - jitter is at the very bottom of the list.

Quote

what remedies do you suggest?

I suggest you ignore this non-issue and enjoy the music.

--Ethan

bpape · « **Reply #3 on:** 6 Mar 2008, 02:51 pm »

Oh boy. Here we go...

Geardaddy · « **Reply #4 on:** 6 Mar 2008, 03:00 pm »

Thanks for the candid response Ethan. I have no hard ideologic positions on this stuff. I have just perused a lot of audio verbage on the topic and wanted people's insights. So, in your humble opinion, is Robert Harely from TAS delusional with his sonic portrayal of jitter in a system?

giantsteps · « **Reply #5 on:** 6 Mar 2008, 03:04 pm »

Quote from: bpape on 6 Mar 2008, 02:51 pm

Oh boy. Here we go...

Yep....I think it's inevitable

pbrstreetgang · « **Reply #6 on:** 6 Mar 2008, 03:25 pm »

I agree to a great extent to Harley in the way that he is describing the perceived texture, layering and extra realism that can be obtained from the better optimization between source and DAC. However and this is were Ethan is coming from I think some of us simply disagree on what is obsessive and what is actually a positive and tangible difference that can be justified in cost and need. I mean why the nit picking and I will argue that many things will make a more perceived difference in sound that add on jitter reducers ASRC ect between the same two components. Why not just get a different source or DAC to try? That would be more of a sound difference. So what if you have SOTA jitter levels and still dont like the sound of the component?

Im not sure if my arguments could be applied to the boutique and stand alone reclockers and jitter reducers available at a hefty price as I have not put my money down to try one and I will not opine about what I think their effect might be.

Geardaddy · « **Reply #7 on:** 6 Mar 2008, 03:41 pm »

pbrstreetgang and Ethan, I agree with your sentiments. There is obviously a lot of money to be made riding the server-based music wave, and it is nice to demystify some of the newer technologies that are springing up that claim to splay CDPs. My personal opinion is that it will some time before things simmer and settle and the technology is actually affordable....I am not inclined to spend 5K or more on an atomic reclocker or MP....anyway, I am still waiting for the pro-jitter camp to chime in...

pbrstreetgang · « **Reply #8 on:** 6 Mar 2008, 03:53 pm »

Look, I agree jitter makes a difference especially in the way Harley said it and I think he nailed it. The question is if we are someone like Harley and a ASRC, or jitter reducer is the last tweek before his fully optimized and carefully tweeked system needs for perfection then fine. I already know Im getting better sound and enjoyment out of my sonos and DAC than I ever had from ~2K cd player or any other source I have used. Of course I know there are super cd players from Esoteric, MBL and APL. There are also better speakers, and better amps and better.... You get the idea

Geardaddy · « **Reply #9 on:** 6 Mar 2008, 04:06 pm »

word....I fiddled with the Sonos at a friends house a few weekends ago and it is certainly a nice interface. I have another friend who is very happy with his Sonos using the digital out through a Halcro processor....and he is very happy with it.

woodsyi · « **Reply #10 on:** 6 Mar 2008, 04:10 pm »

I don't know what signature jitter has. I am guessing it just clouds up a bunch of things. Accurate digital signal transfer depends on so many factors. I found that clean power supply is critical in streaming digits out of digital files. This makes sense as why PS is so critical for Squeezebox. Physical transport would have to deal with mechanical instability as well. I recently tried a different tack. I got a Pace-car from EA to slave the Squeezebox. It's not an atomic clock but a Super Clock 4 is probably better than the one in an SB3 if only because it would have an external PS. Anyway, when comparing the sound through my DAC (Northstar 192) I can hear a difference between music reclocked with Pace Car vs. music steamed out of SB3 directly to the same DAC using SPDIF. For example, a lot of instruments are played in Paul Simon's The Rhythm of the Saints. I always assumed that it was recorded in the field with less than ideal recording conditions. Apparently not. The reclocked Pace Car version puts all the instruments in place. For the first time I could locate individual instruments and separate drum beats. Only change was the way .flac file was transported to the DAC. Was it jitter?

pbrstreetgang · « **Reply #11 on:** 6 Mar 2008, 04:15 pm »

Yes I agree that it was mostly jitter. The EA looks very nice and I didnt mention it as it costs more than my DAC and Source and I didnt lay out money to try it so I can have no opinion of it. With the options you seem to have got and the improvement in you Paul Simon disc what do you think of the cost/performance of your jitter reducer? BTW what options did you get and how much?

Rx8man · « **Reply #12 on:** 6 Mar 2008, 04:45 pm »

Woodsyi heard a difference and pretty much described the same thing I hear, a "cloudy bunching up of things" and his mention of power supplies are critically important.

Bottom line is, you don't know till you don't hear it, and I have.

To me, it's a timing issue (algorithm) in the processing chip, when the 0s and 1s are correctly aligned, the presentation becomes intelligible and continuous.

It's (almost) like comparing a Koetsu or Dynavector to something of a way less caliber, you get the big picture more clearly.

pbrstreetgang · « **Reply #13 on:** 6 Mar 2008, 05:02 pm »

Fair enough, would you say the difference in jitter is more than just upgrading components to the next price bracket? Is it worth messing with jitter devices instead of just a better source and DAC? Why even mess with budget sources and DACs and jump straight to the big dollar stuff? At what point is a product finally competent in jitter to start?

All I know is two budget components in my system do a pretty darn good job when compared to one box CD players under 2K that I have used. While we are on the subject there are only a couple of the many high dollar systems I have had time with that I can honestly say are worth the price and considerably out do my more modest system. Sorry If I have been in any members home here and you feel like this is a slight but there are very few I have evaluated that are unquestionably better and not just different preferences but in the same sonic league. More often than not audiophiles systems sound in the same league with individual personal preferences when properly set up. My experience only YMMV.

Geardaddy · « **Reply #14 on:** 6 Mar 2008, 05:19 pm »

pbrstreetgang , I found your sentiments reasonable. At what levels is jitter unreasonable and what approach is best? Can we take a jitter-ridden source like the Sonos (like some claim...a few modders I spoke with won't even touch these devices) and cure it with a DAC/reclocker, etc? Steve N. at Empirical Audio claims you can with his Pacecar. The source becomes less relevant with good anti-jitter technology. Do most current DACs do an adequate job in this arena? Anyway, according to Harley, jitter is easily discernable by the human ear:

"If as Joe Harley observes, the ear can easily discern improvements in word clock accuracy down to +/-0.05 parts per billion (translating into jitter reductions on the order of tens of pico seconds), then it would appear that there's still a long way to go toward true SOTA in digital sound. Better clocks are far from an exercise in diminishing returns."

Bob in St. Louis · « **Reply #15 on:** 6 Mar 2008, 05:20 pm »

I am not picking sides, and I am certainly not getting in the middle of the storm that's building but this is a topic I'd like to learn about.
That being said, there are downloadable jitter demos available on the net. Simply Google: "jitter demonstration".
Also, some Stereophile CD's have jitter demo tracks.

Now that I've thrown raw meat into the cage, I'll run away now.
Carry on gentilemen.

Bob

Geardaddy · « **Reply #16 on:** 6 Mar 2008, 05:23 pm »

Stong contribution Bob....

pbrstreetgang · « **Reply #17 on:** 6 Mar 2008, 06:11 pm »

I hear the cries of "worst wi-fi jitter" But from Stereophile
"The calculated jitter level was 388 picoseconds peak–peak, which is low, especially considering how much processing is performed within the ZP80 and Sonosnet."

As opposed to the $44,000 Zanden Transport/DAC from Stereophile
"The jitter level was high, at 1018 picoseconds peak–peak, which is more than four times the jitter of the best-performing components on this test."

The mod worthy squeezebox from Stereophile
"These are relatively low in level. The calculated jitter level was 321 picoseconds peak–peak, which is low. Most of this comes from sidebands of unknown origin "

So, the Sonos is bad high but the Universially praised and modded DAC-1 from Stereophile with its world class jitter reduction
"these are low in level, and the Miller Analyzer reported just 157 picoseconds peak–peak of jitter"

sts9fan · « **Reply #18 on:** 6 Mar 2008, 06:16 pm »

Now how exagerated are these demo? How does the jitter of your sytem effect the demo? How can you listen to a jitter free demo with system jitter?

Kris

Geardaddy · « **Reply #19 on:** 6 Mar 2008, 06:25 pm »

Quote from: pbrstreetgang on 6 Mar 2008, 06:11 pm

I hear the cries of "worst wi-fi jitter" But from Stereophile
"The calculated jitter level was 388 picoseconds peak–peak, which is low, especially considering how much processing is performed within the ZP80 and Sonosnet."

As opposed to the $44,000 Zanden Transport/DAC from Stereophile
"The jitter level was high, at 1018 picoseconds peak–peak, which is more than four times the jitter of the best-performing components on this test."

The mod worthy squeezebox from Stereophile
"These are relatively low in level. The calculated jitter level was 321 picoseconds peak–peak, which is low. Most of this comes from sidebands of unknown origin "

So, the Sonos is bad high but the Universially praised and modded DAC-1 from Stereophile with its world class jitter reduction
"these are low in level, and the Miller Analyzer reported just 157 picoseconds peak–peak of jitter"

Word pbrstreetgang. This is what the anti-CDP doomsayers are proclaiming...even the cheesiest server-based system smokes CDPs in terms of jitter. Anyway, it would be nice to sit down and hear these things in blinded experiment....