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Clock synchronization issue?

After a lot of experimentation lately I've come to the conclusion that there is a lower mid-range/upper bass frequency dip when using my Simaudio 650D with my Sooloos MC200. This dip doesn't occur with the other DACs I tried with the Sooloos nor does it occur on cd play through the 650D. My Sooloos dealer thinks it may be a clock synchro nation issue between the two units and is thinking that inserting some sort of re-clocking device between the two units may resolve the issue. Any thoughts or similar experiences you could share to help me out?

FYI, the Sooloos up samples the digital signal to 88.2 kHz and applies an apodising filter before outputting the digital signal. I'm not sure if the 650D also uses some sort of up sampling as well.
camb
camb OP
164 posts
 
Just an update...I tried using an Arcam CD player as a transport, feeding the Simaudio 650D through the same S/PDIF rca input as the Sooloos. The sound was perfect - pretty much identical to using the 650D's own transport.

So, this must be an issue of compatability between Sooloos and the Simaudio 650D.

One other finding - the Sooloos/Simaudio 650D combination sounds more like the 650D's transport/dac combo when the Sooloos upsampling/apodising filter is switched off (more open sounding, although not as "rich").
audioengr
3,282 posts
 
You are probably experiencing either the effects of jitter or some format handling strangeness with the Sooloos. Its not a synchronization or compatibility issue. Jitter, ripping software and playback software can all have a dramatic impact on the SQ. Picking the optimum of these is critical in computer audio systems. Jitter is the most difficult thing to keep low at low frequencies. Clocks that accomplish this are very expensive.

Most all-in-one systems that I have had in my system were dissappointing either in the ripper or the playback software or both. All had higher jitter than I am used-to.

This is why I recommend a late 2009 Mac Mini with Amarra or Pure Music and XLD ripper. These all have proven track records with multiple awards.

Steve N.
Empirical Audio
camb OP
164 posts
 
Thanks Steve!

Very interesting, particularly that jitter in low frequencies can be more challenging than at other frequencies.

I predominantly use wave files ripped by Exact Audio Copy (with the program optimized for my laptop). Flac files (ripped by the Sooloos) I find don't sound quite as good.

Strange that so many of the audio reviewers use Sooloos to evaluate audio equipment if it's a limiting factor in sonic quality!

What's interesting is that the sound of the dac in the Sooloos Media Source 600 is quite warm and maybe a tad mid-bass heavy. What's also interesting is that engaging the Meridian up sampling anodizing filter before the digital output changes the sound quite a bit with my Simaudio dac - the music gets slightly rolled off in the treble and warmer in the mid-range.

Any suggestions for getting the best sound possible out of the Sooloos? I love the interface!

Thanks!

Cam
audioengr
3,282 posts
 
"Any suggestions for getting the best sound possible out of the Sooloos? I love the interface!"

If the problem is jitter, which is likely IMO, then the solution is to reclock it with a resampling reclocker like this:

http://www.audiocircle.com/index.php?topic=106328.0

You will not get bit-perfect, but it will probably sound better anyway.

If the problem is the playback software, there is not much you can do.

I would recommend using dbpoweramp with Accurate Rip enabled to rip CDs.

Steve N.
Empirical Audio
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