[hciman77]

I just downloaded Arny Kreuger's "jittered" wave file (16 bit 44.1khz) samples and his PCABX comparator. There are 5 Piano samples, Unjittered, jittered with a -20db 60Hz jitter signal, a -40db 60Hz jitter signal, a -60db 60Hz jitter signal and a -80db. 60Hz jitter signal.

Kreuger opines that a -80db jitter level will be inaudible in real world applications. If I read it right the implication is that a -80db jittered signal would be indistinguishable from an unjittered sample and that jitter in the -80db range would be essentially inaudible.

Using the blind comparator I could not distinguish between the -80db jittered signal and unjittered signal. I tried this several times blind. Okay it was a pretty short sample and my soundcard is pretty naff so it may not signify too much , but I will burn the samples to CD and try playing them back on my CD rig on random and see if I can tell the difference.

Kreuger infers that a jitter level of -80db is well within the reach of all un anti-shock enabled PCDPs (the anti-shock really knackers the jitter figures apparently).

His bank of tests show the worst result is the Sony D220 which clocks in at -85db, for comparison the bog-standard Marantz CD67Se clocks figures of -105 dB(Analog) -130 dB(Coax) -130 dB(Optical) . The Marantz has legendarily bad jitter figures and has been measured as having jitter of around 650 - 700ps according to the Reference Mods bunch, which by modern standards is dreadful and equates (they say) to 14 bit performance.

Kreuger defines the jitter figures on the Marantz as "Excellent" and they are superior to all the PCDPS and soundcards he measured.

So what is going on here how do I compare these different figures one is a ratio measure (db) and the other is a timing measure (ps) ?. The implication seems to be that one the one hand that even the 67se has jitter levels that are so low as to be utterly meaningless on the other hand it is in terms of jitter a piece of junk and as bad as a first gen player from 1981.

I am more confused now than before.

 

[Garbz]

And that confusion won't get better after this post. I'm not even sure if the dB level of jitter can be compared to the ps, unless more information is given about the sidebands, and where they are located, or what frequency the jitter happens at.

Further more different tests for jitter will give different results. Without a standard method for testing who knows how much jitter certain item has. I know one magazine (stereophile I think) said the Pioneer DV 676 was rated well for jitter, another (hifi choice?) said it was poor.

Also the high C on a piano has a frequency of around 4khz IIRC. So according to Julian Dunn 100ps or so is the limit to jitter affecting a piano's fundemental sounds. The figures would change when talking about drums, a double bass I doubt would be affected at all except for the extreme transients. Meh all too confusing, just listen to your music.

 

[grandenigma1]

If it sounds good it is good

 

[hciman77]

Quote:

Originally Posted by Garbz /img/forum/go_quote.gif Meh all too confusing, just listen to your music.

Word, by the way congratulations on the first test.

 

[regal]

You have to think that with some transports costing $13k there is something very real and bad about jitter. I am as big a conspiracy theorist as any but cannot believe that a company would design and sell a $13k transport if there wasn't something to be gained by lowering jitter.

Anyone with a $13k transport want to do a side by side comparison with something high in jitter like a computer soundcard or that $50 phillips DVD player?

 

[Garbz]

What's the first test :?

Regal hifis in general follow the a certain equation. With regards to spending on your source I think the equation looks like y = x^50, where y is cost, and x is benefit

Jitter is a very very real and damaging issue IF you are trying to reach the last echelon of audio perfection. Even with jitter you can get some very good sounding equipment, but very good sounding just doesn't cut it on the high end. To get the best possible performance from a DAC there can't be any jitter, and naturally there are companies that cater to customers wanting that.

 

[jandl100]

Hi

IME CD transports can have a large affect on sound quality. Night & Day, IMO. But ... and this is a BIG but ... I find that using one of the cheap DVD (yes, DVD) players coming out of China these days can equal the best audiophile transports. (yeah, I know ... here come the Flames!

). I've owned Mark Levinson 36/37, Linn Karik, Cyrus DacMaster transports and other audiophile CDPs with a digi output - and I find my $30 Alba DVD player (bought from my local supermarket) is at least as good. Honestly. It sounds superb. I used to have a cheap Yamada DVD player (not YaMaha) - until I dropped it! - which was also excellent (see my recent letter in Stereophile), and was how I discovered this seemingly stupid/ridiculous effect. These cheap DVD players simply DESTROY regular CD players used as transports. The on-board DACs though, are of course horrible. Just get a cheap and cheerful Chinese DVD player with a co-ax digi output into a good DAC. You WILL be amazed.

 

[thomaspf]

Quote:

Originally Posted by hciman77 This is an interesting pdf - http://akmedia.digidesign.com/suppor...tter_30957.pdf the authors duscuss a new clocking protocol and its low jitter capability - typically 50ps. Then they discuss comparative listening tests with it and other (technically inferior) clocks and conclude.

This paper has created quite a bit of stir in the community and led to the situation that Dan Lavry got kicked out as moderator on the PSW forum.

The discussion was a bit complex to follow but somehow the supporters of "jitter might make the sound better" could never really explain why that statement could ever be true. Eventually the discussion derailed into an argument about external clock generators which hit a sensitive spot with the companies who make those.

I think I am safely on the side of investing in a better DAC rather than believing that an external clock that adds jitter could magically improve the sound of an existing DAC.

Cheers

Thomas

 

[Mr_Sukebe]

Quote:

Originally Posted by regal /img/forum/go_quote.gif Anyone with a $13k transport want to do a side by side comparison with something high in jitter like a computer soundcard or that $50 phillips DVD player?

My transport only cost around $5k when new, but has been clock modded and uses higher quality power cables. I've compared it with my $100 Pioneer DVD player into a couple of different DACs and think that there is an obvious and noticeable improvement.
Still, if people wish to reply that this can't possibly be true because of XXXX, then that's fine by me as I'm going to listen to some more great tunes.

 

[MiChael.]

Quote:

Originally Posted by regal /img/forum/go_quote.gif You have to think that with some transports costing $13k there is something very real and bad about jitter. I am as big a conspiracy theorist as any but cannot believe that a company would design and sell a $13k transport if there wasn't something to be gained by lowering jitter. Anyone with a $13k transport want to do a side by side comparison with something high in jitter like a computer soundcard or that $50 phillips DVD player?

13k transport or car, hmm top choice.

And would there be any money left for the DAC ?-)
Perhaps money loan from bank and paying that shiny fabulous transport couple year

and another 13k for DAC and 13k for "pefect" toslink cable.

With 13k it would be possible to hire bands to play in your living room.

 

[regal]

You can get a surprisingly good car for $1000, My wife drives a pristine $1000 '89 Honda Civic which will last her at least 10 years.

 

[hciman77]

Quote:

Originally Posted by thomaspf /img/forum/go_quote.gif This paper has created quite a bit of stir in the community and led to the situation that Dan Lavry got kicked out as moderator on the PSW forum. The discussion was a bit complex to follow but somehow the supporters of "jitter might make the sound better" could never really explain why that statement could ever be true. Eventually the discussion derailed into an argument about external clock generators which hit a sensitive spot with the companies who make those. I think I am safely on the side of investing in a better DAC rather than believing that an external clock that adds jitter could magically improve the sound of an existing DAC. Cheers Thomas

I think there is a danger of confusing coincidence and causality. My reading was that some systems using inferior clocks were preferred to a system using a technically better clock.

Unless the clock is the only variable changed in all cases then there is no direct connection between the clock change and the perceived quality.

Even if a direct swapping of one clock for another gives a reliable effect that does not prove anything specifically unless jitter and only jitter was the dfference between the two systems i.e all other measurable characteristics were absolutely identical.

If after that you compare two systems and the system with more jitter but otherwise identical is reliably preferred to the lower jitter system then you have an interesting artifact.

 

[Sleestack]

Quote:

Originally Posted by regal /img/forum/go_quote.gif You have to think that with some transports costing $13k there is something very real and bad about jitter. I am as big a conspiracy theorist as any but cannot believe that a company would design and sell a $13k transport if there wasn't something to be gained by lowering jitter. Anyone with a $13k transport want to do a side by side comparison with something high in jitter like a computer soundcard or that $50 phillips DVD player?

I have a $13K transport and partner DAC. I also have a $3K dedicated redbook transport (w/o DAC). Someone bring over a $50 DVD player and I'd be happy to let them A/B.

 

[audioengr]

Quote:

Originally Posted by thomaspf /img/forum/go_quote.gif This paper has created quite a bit of stir in the community and led to the situation that Dan Lavry got kicked out as moderator on the PSW forum. The discussion was a bit complex to follow but somehow the supporters of "jitter might make the sound better" could never really explain why that statement could ever be true. Eventually the discussion derailed into an argument about external clock generators which hit a sensitive spot with the companies who make those. I think I am safely on the side of investing in a better DAC rather than believing that an external clock that adds jitter could magically improve the sound of an existing DAC. Cheers Thomas

I can understand your being suspicious of this. However, if the external clock drives the D/A chip directly, such as in an I2S interface, the jitter can be extremely low. It is just like having the clock right next to the D/A chip. It does not get any better than this....

Word clocks however are fraught with problems, not the least is the fact that most modern DAC chips do not do the conversion using the word clock, but rather the bit-clock or even the master clock. When folks ask how to do a word-clock, I just say "forget it".

Steve N.

 

[thomaspf]

I agree. In the PSW forum the discussion got really irrational with the vendors of external clocks in one corner and the Dan as a builder of DACs in the other corner.

Clock generators make a lot of sense if you need to synchronize a larger number of devices but there was no rational argument why it would increase the quality of a single playback device that could not be achieved better by improvements in the DAC.

It got completely esoteric when the claim came up that higher jitter from an external clock would actually improve the sound.

Cheers

Thomas