Problems with changing sample rates w/ optical device

[andydunham]

Hi all, I'm having trouble with my PT LE system recognizing my Motu 8pre into my 003 console @96k, 24 bit. I've gotten this setup to work at 44.1 perfectly fine, and I'm doing the exact same process connecting the two devices at 96k, but for some reason whenever I go change the clock source it says "invalid clock source, reverting to internal." I know the Optical connection is working because the Motu is labeled as "converter" instead of "Interface" and the fact that I've had this setup working at 44.1. I'm just curious if there is any special process or anything that I need to do to work at 96k as opposed to the working setup at 44.1? Thanks for any help you can give.

ps, I've searched the forum for answers, but can't seem to find this same problem or anything that has worked yet.

[DigiTechSupt]

Which version of Pro Tools are you running? What are your system specs? Have you tried different cables?

[andydunham]

Thanks for the quick reply Digi. Sorry, I should've included system specs the first time. Here they are:

Powermac G5, Dual 1.8 4gb Ram
Pro Tools LE 7.4cs7 on OSX 10.4.11
Digi 003 Console
Motu 8pre

I have tried a different ADAT optical cable and still without success. It just feels like I'm missing something, like different ports on the back of the Motu, but I've also tried both of those as well. I'll start a new session just to see if things work, setting the I/O settings the same as previous sessions (maybe this is the problem somehow?), sample rate to 96k, and bit depth to 24. Usually I'll run my sessions at 44.1 and 24, but I've been wanting to try 96 just because I can and for school projects as well. I hope this is enough information to describe the situation better. Again thanks for the quick reply and any help you can give!

- Andrew

[DigiTechSupt]

In looking at the 8pre info, it appears it can be clocked to an external source - can you try clocking the 8pre to the 003 and see if that works?

[andydunham]

I'm sort of new to this ADAT/optical thing, so I guess it was half a stroke of luck and half reading that I got the 44.1 to work. When you say "click the 8pre to the 003" does that mean setting the sample rate at the new session screen in Pro Tools and then letting the 8pre read that signal? If so, I've connected the optical OUT of the 003 into the IN of the 8pre and so far it's made no difference. I just figured since I wanted to use the 8pre as my preamps instead of the 003 I should connect the OUT of the 8pre into the IN of the 003. Sorry I'm not up to speed on all of this

[DigiTechSupt]

When you say "click the 8pre to the 003" does that mean setting the sample rate at the new session screen in Pro Tools and then letting the 8pre read that signal? If so, I've connected the optical OUT of the 003 into the IN of the 8pre and so far it's made no difference.

Here's what you'll need to do:

1. Connect the OUT of the 8Pre to the IN on the 003
2. Connect the OUT of the 003 to the IN on the 8Pre
3. Set the 8Pre to clock to an external source - in this case the incoming ADAT signal from the 003.
4. Set Pro Tools to internal clock in the HW Setups dialog.

This should allow the 8Pre to clock to the 003 - let us know if that works or not.

[The Dougfather]

Motu 8pre into my 003 console @96k

Unless anything has changed Pro Tools supports a maximum sample rate of 48khz through ADAT, also Digi hardware doesn't support the smux feature to allow 96khz through ADAT.

[andydunham]

Thanks for the response Dougfather. Not that I don't believe you (since I'm clearly no expert on this), but tech support seems to believe it's possible from what I've read so far. DIGI : is this true? That PT and Digi hardware will only allow a maximum sample rate of 48k through ADAT? If so, I'll keep it at 48k and be 100% fine with that.

[stoneinapond]

Originally Posted by andydunham

...PT and Digi hardware will only allow a maximum sample rate of 48k through ADAT?...

Correct.

[DigiTechSupt]

Dougfather is right - I overlooked that when diagnosing the problem, as some MOTU devices allow the optical port to function as either ADAT or (2 channel) SPDIF and I didn't think to look to see if that was the case with the 8Pre. Since it only supports ADAT, you're limited to working at 48k.