Digital interfacing / jitter

[DominicPerry]

Hi all,
I've got a theoretical question which makes a difference to what interface I buy for my laptop. If I get a Mic Pre (perhaps a Broadhurst Gardens No1) and a Mytek Stereo96 AD and I want to get this signal into a laptop, I know the RME Multiface/digiface is a good stable option but the jitter specs on the RME is <1ns whereas the Mytek is 10 picoseconds. The RME spec is for both the AD converters (which I won't be using) AND the S/PDIF interface. Will the RME add jitter to the chain? I've read a big slanging match on the subject elsewhere, and there was no resolution to the issue. I would assume that a jitter spec on the S/PDIF input implies that a digital-digital transfer will be influenced by both elements, and I don't believe that 'it's all bits, so it doesn't matter' but I could do with some references to papers which explain the interaction. Any clues please?

Thanks
Dominic

[Craig Allen]

I would think it would matter as to where it was being clocked from - I wouldn't think the RME would add anything if it wasn't the master, it would just pass the data. But don't quote me on this - I could be wrong.

[Naturally Digital]

Hi Dominic,

First off I will say that with that combo I really don't think you'll have anything to worry about... Should work fine. I'd spend more time/effort worrying about the mic, mic position, room, treatment etc. than jitter. YMMV

To minimize jitter you should let the A/D be the master clock so in this case make the Mytek master and sync the RME to digital in. If you want to be extra careful you can connect the wordclock out from the Mytek to the RME and sync the RME to WC.

Bob Katz talks about jitter in his excellent book "Mastering Audio". You may find some articles on his website. Also, I think you'll find some discussion of jitter issues on many of the sites for converters such as Mytek, Lavry, Benchmark, Apogee etc. Not sure, but it's worth a look if you want to dig deeper.

[DominicPerry]

Thanks guys. I'll have a look around for Bob Katz website too.

Dominic