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  #1  
Old 03-30-2009, 02:56 PM
mrcomber24 mrcomber24 is offline
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Default LTC problem on MIX+ deck laybacks?

Ok, so I’ve racked by brain trying to figure this one out. I’m setting up an old MIX+ rig and I can’t layback to either my DSR-80 DVCAM or PVW-2800 decks correctly (analog or AES). I think I’ve narrowed it down to a time code issue because the ONLY way I’ve got it to work is to use Jam Sync. I’ve switched LTC cables/connectors, bypassed the patchbay and plugged right into my USD, but can’t seem to get a stable lock. If I am on “8 frame” or “none” Freewheel settings, everything looks good when it’s cueing up, but when PT hits my insert location—no meters play, and the time code readout in the transport is choppy. If I just switch to Jam Sync, all is good. This only happens when I try to layback. Everything syncs up fine when I’m online and just hit play. Does this sound like a time code problem? If so—what LTC connectors/cables is everyone using to go from a BNC in/out on the deck to either a ¼” or XLR in/out on the patchbay or USD/SYNC?

I’ve tried to list all the pertinent specs below. I have double checked frame rates match up. Hopefully this is just something easy I’ve missed. Anyone have an idea? Thank you in advance if so!

Hardware Setup
PT 6.4.1 TDM on PC
MIX Core (receiving USD and 888/24 cables)
MIX Farm (receiving 888/16 cable)
888/24 (receiving super clock from USD)
888/16 (receiving super clock from 888/24, with “out” 75 ohm terminated)
USD (firmware 5.03, receiving house black from Rosendahl to “video ref”, with “out” 75 ohm terminated)
Machine Control 2.0 option (using Keyspan USA 19-HS adapter)
Rosendahl Nanosyncs (sending house black to all decks and USD)
Deck LTC Out to USD LTC In

Pro Tools Settings
Clock Source=Internal
USD Setup in Session Setup (clock ref=Video Reference; position ref=LTC, format=NTSC)
Machine Control Tab (9 pin serial enabled, “generic 2 ntsc” for DSR-80, preroll=150 frames, “use serial TC for position ref” is NOT checked—I’ve tried both)
Sync Tab (USD selected on the digiserial port, Min sync delay=15 frames)
Drop insertion marker, switch transport to machine, arm track 1&2, click online and hit record
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  #2  
Old 03-31-2009, 01:16 AM
Postman Postman is offline
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Default Re: LTC problem on MIX+ deck laybacks?

I'm not sure what you mean by "Clock Source=Internal" because that is not right. The clock source should be the USD, with all the other settings you have already, but then you later say the USD is selected on the Sync Tab. The other observation that sounds odd is:
Quote:
If I am on “8 frame” or “none” Freewheel settings, everything looks good when it’s cueing up, but when PT hits my insert location—no meters play, and the time code readout in the transport is choppy.
Pro Tools meters stop working? What timecode readout is choppy? The one on the deck itself? Both decks behave that way? I would not expect the deck to have trouble reading its own code under any circumstance.

This sounds like a problem I encountered at another facility once, and it was operator error (me), but I cannot for the life of me remember exactly what was wrong or how we fixed it and I am not in my studio to check myself now. It is NOT a problem with your cabling because you can chase the LTC okay.
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Old 03-31-2009, 07:34 AM
hummerZ hummerZ is offline
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Default Re: LTC problem on MIX+ deck laybacks?

Clocking internally would cause this. Barring that, just to rule out a problem with your house sync, try clocking off of an AES line from the deck.

Also, double check that the TC rate is correct.
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Old 03-31-2009, 08:26 AM
scottgreiner scottgreiner is offline
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Default Re: LTC problem on MIX+ deck laybacks?

Quote:
Originally Posted by hummerZ View Post
Clocking internally would cause this. Barring that, just to rule out a problem with your house sync, try clocking off of an AES line from the deck.

Also, double check that the TC rate is correct.
Does the layback work analog?
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  #5  
Old 03-31-2009, 05:20 PM
mrcomber24 mrcomber24 is offline
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Default Re: LTC problem on MIX+ deck laybacks?

Thanks for everyone's replies. Really quickly:

1) I have the same problem with Analog or AES laybacks
2) Tried clocking off the DVCAM AES out--no luck
3) Time Code frame rates do match up
4) In Session Setup, for "Clock Source"--all I can select is "Internal" or "AES/EBU". Should I be able to see "USD" or something else? I do have the USD selected on the Digiserial Port in the Peripherals/Sync tab. In Session Setup--I can also select all of the "Clock Reference" options for the USD. When I select Video Reference, both the "Locked" and "Speed Cal" lights are solid--so that's good.

5) When I say the meters stop working and the TC readout is choppy, I'm referring to PT. The decks behave fine. I know the meters not playing while doing a layback is often a sign of bad TC or Clock sync.

**Update--I did just try to do a DVCAM layback by selecting "Use Serial Time Code for Positional Reference" and it seemed to do it fine with having to use Jam Sync. What is everyone using for their laybacks to decks--analog LTC or Serial TC through the RS-422 connections? I've always used analog LTC in the past.
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  #6  
Old 03-31-2009, 05:41 PM
Postman Postman is offline
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Default Re: LTC problem on MIX+ deck laybacks?

LTC or Serial TC, it should work either way as long as you're not trying to regen the code while using serial. I always used analog LTC with 6.4 and earlier because there used to be some problems with absolute sync and serial code. I think the problems were resolved in 6.4, but I wouldn't swear to it. I have to bow out of this one, I haven't used 6.4 software in many years and I just don't remember if Clock Source choices should be limited to Internal and AES while the USD is online with PT. It doesn't sound right to me now but I don't want to commit to that. I used to have three of those systems but, well, I don't remember basketball scores either. I only ran 6.4 on Mac anyway and you have PC. Sorry I cannot help more.
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  #7  
Old 03-31-2009, 10:58 PM
mrcomber24 mrcomber24 is offline
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Default Re: LTC problem on MIX+ deck laybacks?

Thanks so much Postman, and to the rest of you. I won't be regenerating any time code, so Serial Time Code may have to be the trick until I can figure out what's going on. It seems like LTC should be more than doable, and the "correct" way--but I can live in the meantime. Thanks again!
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