[skibum]

I found some info about this in the Audio Circle forums from back in May. Basically save music files (in any format) and then run the files through Audacity (which is free!) and do a spectrum analysis. With some simple calculations someone was able to tell the differences between 4 random music clips that had jitter artificially added.

I did the same thing and got the same results...

Anyone out there spend any time on this?

[claytontstanley]

Did you have to have the incorrect 3 files to compare to the correct file in order to determine the correct file?

If the correct file could be determined without having to look at any other files for comparison, then that shows that there's a unique solution to separating out the jitter (noise) from the music (signal), which I would not think is the case.

I haven't tested any of this stuff, but I'm very interested in results towards this end. Think about all of the jittery online sources (e.g., youtube, my computer-based tivo, bowling alleys) that could have their sound much improved if we could partial out the jitter from the source. But again, I tend to think that jitter gets embedded into the signal, and there's not a unique solution for separating the two after they've been summed together.

But I could be wrong. I mean, our ears can separate summed signals very well (spatial location of different instruments), so it may be possible to 'spatially' separate jitter from the signal...

-Clayton

[skibum]

There were 5 files.  Each with an unknown amount of jitter.  If you did a spectrum analysis of the 5 files you could see differences in amplitude at each frequency.  Using this information it was fairly easy to measure differences between each file.  But I am not convinced you can tell which file has more or less jitter.

I am interested in this because I am modifying  a Valab DAC and want to build a audio media server using this DAC.  I want a way to measure differences (besides just listening).  I am looking at possibly using the new National Semiconductor  LMK04000 "jitter cleaner" or something equivalent. 

What I need is a inexpensive/simple way to somehow measure jitter..... 

[jtwrace]

skibum

You might find this interesting:  http://www.computeraudiophile.com/content/Some-additional-thoughts-about-measuring-jitter

[skibum]

Thanks for that jtwrace!  Great Thread.

skibum