Why does this work?

[RBIngraham]

The Raydat must sync the spidif in on its own because I have been using it this way for a long time with no audible ticks pops of any kind even with different clock timing and running down 150 foot of cat 5 stranded cable.

Butch

OK, just because I was curious... I actually went to the web site and looked at the manual. What a concept.

http://www.rme-audio.de/download/raydat_e.pdf

Go to page 18.

It doesn't sound to me like the RayDAT is designed to reclock in incoming SPDIF signal.

So I'm not sure why this has been working out for you so well. The only thing I can think of is that maybe you have the clock set to Autosync? And it has always just been the master clock when you don't have your laptop hooked up and then it locks to the laptop when you plug it in?

That's just an educated guess based on what I've read in this thread. While I have used and spec'd RayDat cards I don't own any, so I'm only an occasional user, not an everyday user.

I would probably suggest you make sure your sync settings are all set correctly. Or I would just let the remote laptop be the wordclock master and not worry about it.

Anyway good luck solving the mystery and hopefully it doesn't break in the process.

[Yogi]

Per the spec on spdif the input circuit must be able to lock to the incoming signal. Consider this, UNLESS there is a signal being returned to a spdif source there is NO WAY to sync it. The input must be able to accept the incoming signal and figure out what it's bitrate and number of bits are from the incoming signal. Once it's done that it can easily add that data into any other datastreams.

[RBIngraham]

Per the spec on spdif the input circuit must be able to lock to the incoming signal. Consider this, UNLESS there is a signal being returned to a spdif source there is NO WAY to sync it. The input must be able to accept the incoming signal and figure out what it's bitrate and number of bits are from the incoming signal. Once it's done that it can easily add that data into any other datastreams.

Yogi, I think you are missing what I was talking about. There is a difference between being able to lock the wordclock to an incoming SPDIF signal and being able to reclock incoming SPDIF signals. Any hardware I know of that has an SPDIF input is capable of being able to use that input source as it's master wordclock, which then obviously put everything in sync, assuming you don't also have other digital inputs.

Some hardware is capable of taking that input and even though it's Master Wordclock is not locked to that input, it will resample that input data and in that process lock that data to it's master wordclock. One example I know of that is able to do this is some of the Yamaha digital consoles. Not all, but many of them. Some of them only do this when you're using one of the card slot I/O bays. But there are instances of hardware that are capable of properly receiving an SPDIF stream even though it's not resolved to the same master Wordclock.

I will say that hardware is few and far between, so you should never count on it doing that. But it does exist.

Or are we saying the same thing?

[kruntz]

Some hardware is capable of taking that input and even though it's Master Wordclock is not locked to that input, it will resample that input data and in that process lock that data to it's master wordclock. One example I know of that is able to do this is some of the Yamaha digital consoles.

Two more examples:
1) Behringer DDX3216 (spdif input)
2) Alesis iO|26 (*two* adat inputs...)

[Yogi]

Or are we saying the same thing?

Essentially. The spdif input port was supposed to be able to bring in digital data from any source and lock onto it without having a sync going out. In cases where there was other digital data present from other sources like the raydat or the 2408 it is supposed to accept data from the incoming source and combine it with other digital data by buffering it until the data packet from the sources that are synced is accumulated. Lump all the data and send it on it's way. Of course if the input spdif port is capable of receiving data and/or sync it is required to sync up. I've seen some Yammy consoles that REALLY didn't want to play nice in this sandbox.

[Butch Bos]

Update
I checked at a gig today and the raydat IS set to master
The Spidif shows locked and even when I change the source from 44.1 to 48K
The raydate shows the sample freq correctly and always locked
I also tried going from spidif out on my laptop to the AES in on the host
and got the same results
So it not only locks but will resample as well

Butch