Timing error/jitter reduction

[Jud]

Hi, Peter. :-) Forgive my amateur understanding of the subject as I ask a couple of questions.

 

But since the same averaging is let loose on music data which is not periodic at all, I tell you

 

Except for, e.g., percussion, string plucks, the "attack" on brass instruments ("tonguing," we used to call it), etc. - and I know those are huge exceptions - isn't music periodic in some sense, i.e., the Fourier transform sense? Yes, not perfectly periodic since we don't have infinities to work with, but a pretty fair approximation?

 

Transients are smeared up to sheer echos at times, and while this is not any representative of any original music at all, it is this what can be improved upon by lower jitter.

 

This sounds to me like a description of timing errors in the analog domain, rather than the analog effects of timing errors at the point where digital information is converted to analog (jitter). From my reading, I thought the "classic" analog effects of jitter are frequency modulation distortion and raising the noise floor. Is this the same thing you're describing, or something different?

 

[barrows]

Hi,

 

Thanks for more details of your experience. I have no problem with Guido Tent's oscillators, and have not tried them here, perhaps I will sometime...

Right now, I am happy with the improvement I got with the Crysteks, especially once I got their isolated power supplies sorted. I really do not consider the RMS jitter specs, and certainly the long term (ppm) specs of good oscillators are pretty irrelevant to audio performance-I just look at the phase noise plots, and pay the most attention to the plot

[Wavelength]

Forrest,

 

You do know I make AD/DA in the 500 series which is a PRO product and has Word Clock? If not... I think that I have really good experience in this area.

 

Look if you don't understand how and what makes Audio related jitter a problem, then you only adding to the problem... not the solution.

 

Thanks

Gordon

 

[Boy Howdy]

Jud:

I tried but Jason responded (very politely) that they were a very small startup and didn't have the resources to get into technical discussions.

 

This is quite understandable since they just released the Bifrost. I ordered one so I could compare it in my systems along with my V-Link + V-DAC.

 

Back to my reading...

 

[Jud]

This is quite understandable since they just released the Bifrost. I ordered one so I could compare it in my systems along with my V-Link + V-DAC.

 

I got an e-mail Jason's wife Rina sent at about 2:00 one morning regarding shipping of my unit, so yeah, I don't think they were getting much sleep right around the USB release date.

 

Will be interested to see what you think when you get a chance to burn in the unit and give it a listen.

 

[Jud]

Look if you don't understand how and what makes Audio related jitter a problem, then you only adding to the problem... not the solution.

 

I'd very much like to read an explanation of how and what makes jitter a problem. This is for the purely selfish reason that I'd value a chance to learn from someone who has knowledge and experience regarding a subject about which I'm intensely curious. So if you're willing...

 

[Talos2000]

Jitter (as originally raised as a digital audio replay issue in the early 1990's) is just a timing question. The right signal at the wrong time is the wrong signal.

 

André Previn (to a comedian playing Grieg's Piano Concerto very badly): "You're playing all the wrong notes!!"

Eric Morecambe: "No, I'm playing all the right notes. Just not in the right order!!"

 

It seems to me that a whole bunch of things that boil down to noise, interference, EMI, and other such stuff, gets lumped into one big pot and labelled as "jitter" because they have the capability to impact the "timing" of the D/A process. Calling all that stuff 'jitter' - in my view - seems to be at least partially responsible for the confusion you seem to be expressing. Just my 2c worth, and I don't have a small fraction of Gordon's credentials or knowledge, so I defer to anything he might want to say in response to that ...

 

[barrows]

No expert here, but my simple understanding is that jitter at the DAC produces noise/distortion products on the analog outputs which are not harmonically related to the signal: hence quite objectionable subjectively.

 

[Wavelength]

Jud,

 

Jitter effects a number of attributes. The big thing is the interpretation of the music seems to fall apart. Things like staging, dynamics etc...

 

I listen a lot different than other people. Being a musician all my life basically makes me listen to each instrument and try and isolate them from the other parts of the music and tear down what they are playing.

 

With music that has a some/lot of jitter it makes my head spin when I listen to stuff.

 

Thanks

Gordon