MOTU 828 transfers via ADAT- popping out of sync

4 replies [Last post]
Joined: 01/12/2004

i was doing some digital transferring from adat to my computer (audio desk)
via adat optical. just a basic transfer. first time i had actually done it.
everything was synced and working fine, but occasionally audio desk would
stop recording. it would just pop out of record. any ideas? could this just
be a processor performance thing and i need to assign more memory? i read
that when you first install audio desk in os X it optimizes your memory
allocation for best performance, but...

im syncing by using the smpte out of the datasync. i am not using the adat
sync because the 828 doesn't have an adat sync out and i needed the time
code to to get back to the data sync so i could send it to the panasonic da7
mixer. there is a smpte out on the datasync so i used it and it seemed to
work fine. sample accurate and lock up was good. except for the whole
popping out of record thing. but not sure if that's a hardware or software

anyway, thanks a lot!

Joined: 02/12/2009

Perhaps there's a threshold of allowable SMPTE drift that it sometimes crosses? ADAT sync is much more stable- you should use that instead of SMPTE if possible. It's worth the trouble.

I'm not as familiar with Audio Desk (I use DP) so I don't know its sync features (I thought it didn't have any). See if there is a tolerance for SMPTE drift that can be increased in number of frames. Does it happen at the same place each time? Then there might be a drop-out at that point on the master, or check that the frame rates are all the same and there's no pull-up or pull-down.

Since the 828 does have ADAT sync in (but not out), and timecode out, maybe you could make the 828 the slave and then spit out TC from the 828 to the DA7. Hmmmm...

re. memory optimization, In OS X there is no user-adjustable memory allocation- it's all automatic.

Joined: 01/12/2004

thanks tony! i don't have the smpte card for the da7, so my only option is
to use MTC. so i think the datasync is the only thing i can do for now.
actually, i might hope that since the timecode is going to two dif places,
but coming from the same source (datasync), it might lessen the chance of
drift? eventhough it's sending out both mtc and smpte (same thing as far as
i know), i would hope that the 828 and the da7 would be getting the same
numbers right down to the frame. i don't know...
anyway, i will check the latency and all that. i wasnt noticing any drift
when tracking and listening back to tracks on the computer synced to the
adats. it's possible there was some drift, but it would have taken a little
longer for it to be noticeable i would think. and if it's not noticeable,
than i would *hope* that any threshold would not be set that low. anyway,
i'll play around some more and see if it is still happening. oh, i'm almost
100% sure the frame rates were matching. not sure if it stopped in the same
place. it didn't happen every time, just some times. so i have no idea.
argh. fun fun.

thanks so much for the response!

Joined: 02/12/2009

And don't forget that the 828 has MIDI out too, maybe it could send MTC...

Joined: 01/12/2004

hey, just wanted to say thanks again. you came through again! big
help. i ended up being able to use the adat sync and then send mtc from the
828 to the da7. seems to be working ok. hopefully it will stay that way.
really appreciate the help! talked to motu tech support and he said smpte
could've been just crapping out, but adat sync is more accurate for my set
up anyway. hopefully when (or if) i really need to use smpte, it'll work.

thanks and take care,

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