Sync'ing my setup

[Berrevd]

Hi,

sorry if this already popped up somewhere else on this incredible forum, but I could not find the exact answer to my problem... So here goes...

In December I will be recording a live concert for a DVD release. Track count is currently adding up to 43 so to me this is by far the most elaborate setup I will be doing in a long time. So that's why I want to be as prepared as possible. Audio stuff like splits and mic amps are almost taken care of but synchronization is still puzzling me a bit.

The idea is to have two independent recording setups: my Logic 8 rig as main setup and two HD24's as backups.

Since this will be for DVD, I will be receiving at least SMPTE from the video-guys to sync audio to video.

Now, my Logic-rig will be using a MOTU PCI-242 card, with two 24IO extenders. With this setup I can configure one of the analog inputs as the SMPTE-input and use this to slave Logic to the incoming SMPTE. So far, so good, I think.

However, the two HD24's have no means to slave other than to ADAT sync. I will of coarse be using one connection to sync the two devices, but my problem is the synchronization to the rest of the system...

Questions:
1. Is it important to sync the two setups to a sample-accurate level? Or can they each be using their own word clock?
2. Does the word clock have to be generated by the video-guys, or is it OK if I use one of my own systems as master clock?
3. If I use an external synchronizer to generate the ADAT sync, is it better to use this for both systems? IOW, do I need to use the ADAT Sync In of my PCI-242 in my Logic rig to sync to the converted timecode? What about Word Clock?

There are probably still some other things to keep in mind, so if you guys can enlighten me, that would be superb.

Many thanks in advance.

Grtz,
B-)

[Legacy]

While not being the expert in this area I'll relay some info taught me by my betters (some of whom are on this board).

Usually you'll receive two signals from the video crew:

1) SMPTE as you know

b) Blackburst / video ref - an empty video signal

With only SMPTE you can sync but don't know how the SMPTE relates to the video frames. Once you add BB in you now have a reference of how SMPTE corresponds to the video frames as it goes down.

You need a device that converts BB into wordclock. Every piece of gear needs to be locked to the Wordclock derived from BB. I've used Rosendahls in the past which are great because they will continue to output WC at the last correct rate even if BB is interrupted and will drift back in once BB is restored.

Also check out the Brainstorm SR15+ or similar which take timecode in, alow you to troubleshoot it in nice ways and also provide a similar buffer in case timecode drops during the event.

The other VITAL piece of gear in my book is a big battery backup UPS...

As for the HD24s I believ that the Alesis AI4 which converts to / from AES also has wordclock on it. It may be worth having just for that if you are doing this sort of thing.

Hope this helps. Good luck!

Silas

[Legacy]

To take a shot at one more -

If you really can't find a back up rig that can lock to timecode it's probably not the end of the world. Definitely a bit seat of the pants but if you are confident in the Logic rig's ability to lock and record very reliably you should be ok. I would route the SMPTE signal onto an open track on the recorder and record it as audio for sure.

FWIW the Rosendahl and Brainstorm type gear is available in most larger cities as a cheap rental. Money VERY well spent IMHO.

-Silas

[huub]

But logic can't sync to timecode without ltc to mtc (miditimecode) converter..
You could just download a copy of reaper beta for mac, wich syncs to tc on any analog input, works very reliably.. Or boomrecorder does the same..

If you want to be completely sure there's no drift, and everything stays in sync, go with the rosendahl nanosyncs hd, however, if this is a low budget production, you'll be fine without syncing wc to video.. I've done it on rare ocassions, and never heard a complaint rrom the editing department..
huub

[noamraz]

Hey slutz,

Could you please explain me why the absence of SMPTE T/C should be an issue for editors doing a "live music" show?

As long as all the cameras receive the SMPTE and the audio recorder is synced via a w/c (a blackburst that is converted to w/c actually..) butofcourse.

Best regards, Noam Raz.

[Indrestudios]

Silas - I too have used the Brainstorm SR15 a bunch for basic clean up & D/A applications, but I was always under the impression that if it lost incoming code it would stop outputting code? I know it is designed to deal with dropped frames, but will it keep rolling if it loses input signal all together?

+1 to the Rosendal recommendation. Always best to reference black if available - Apogee's Big Ben does this too.

berreved - you should talk to the video folks and find out if they are locking to a master clock. I've been on plenty of shoots where I make all of the necessary arrangements for black, smpte, etc. only to find out that the film crew is going all handheld looking to wing it in post.

-MC

[Legacy]

Originally Posted by Indrestudios

Silas - I too have used the Brainstorm SR15 a bunch for basic clean up & D/A applications, but I was always under the impression that if it lost incoming code it would stop outputting code? I know it is designed to deal with dropped frames, but will it keep rolling if it loses input signal all together?

+1 to the Rosendal recommendation. Always best to reference black if available - Apogee's Big Ben does this too.

berreved - you should talk to the video folks and find out if they are locking to a master clock. I've been on plenty of shoots where I make all of the necessary arrangements for black, smpte, etc. only to find out that the film crew is going all handheld looking to wing it in post.

-MC

Hi MC,

I think you are correct - thanks for catching this. I was told that it did but (mercifully) have never needed to find out. However, I DON'T see anything in the manual about it. It does reshape and properly mult the signal as well as alarm / report many different issues as you know.

Thanks,
Silas

[Berrevd]

Hi guys,

Thanks for all the replies... Very interesting all this, but it all sounds quite expensive too...

Indrestudios: I indeed intend to contact the video crew ASAP. The first company we wanted to work with indeed wnated to do everything free-running. But for several reasons (lack of sync'ing being one of them) we changed company and as far as I understood they will be using a house clock or something...

I will try to find out what they can deliver me and if they have some conversion box like the Rosendahl available...

Remains the problem that the HD24 can only sync to ADAT. Does the Rosendahl have an output for this too? Are there other devices capable of doing this?

Many thanks..

Grtz,
B-)

[Gerax]

I'd make sure to have a solid and reliable Black Burst or Video Sync source from the video crew. IME locking to SMPTE isn't that mandatory in a shoot that goes down in a single pass... Relative Time Code of the shoot becomes quite useless once the video goes in editing. It could be handy if you plan to shoot rehearsals and the likes for additional material, but for the show the crucial thing is to make sure your recorders and the video recorders are running at the same clock. Once you line up the audio tracks with the edited video you're good to go. Just make sure to have a video of the shoot with the burn in TC, and line up your audio in your DAW setting it a the same Frame Rate (if you are in belgium and working with video I belive it will be 25FpS); just ask for an OMF export of the video with their reference audio track embedded.

Rosendahl (Nanosync) are a tried and true solution to lock your system to the incoming video reference signal. That and feeding the video crew a rough mix of your tracks for reference and editing, should give you more than enough accuracy to have your audio properly synced.

As for the backup system...you can either lock it with MTC and an ADAT line from your main setup (set the recorders not to chase TC or they'll stop if the signal is interrupted) or you can as well use and AES to ADAT converter and lock them to the main synchronizer (Rosendahls also have AES and Spdif outs whcih you can lock to). I prefer to have all systems locked to the same clock, but not tied to TC, so that if my main goes down the other still runs unaffected.

Hope this helps

L.G.

[Berrevd]

Hi Gerax,

Great info. Thx!

We indeed plan to also film the dress rehearsal. So TC could be interesting anyway.

Isn't another advantage of having TC the fact that the main and backup systems' relative timing will be exactly the same, making it easier to spot the areas needed?

Grtz,
B-)

[Gerax]

Recording TC certainly won't do you any bad, but don't make that become an issue.
Having main and backup recorders at the same TC is handy, but once again, TC becomes useless when referring to an edited video; better, it only becomes a positional reference between you and the picture editor in case there's something to be discussed. On top of that, if you happen to use material from dress rehearsals or the likes, you'll need to fit that in and sync it by hand, so TC won't be of any help...Remember that the smallest time unit for video is frame, so in you case there's only 25 in a second. Audio is much much more detailed (48.000 samples for one second of audio containing 25 frames, so you do the math). I've done shoots where the video crew didn't use a TC source for the multiple cameras (thumbsup ) and ended up syncing my multitrack in Pro Tools to the reference audio track I gave them during the shoot. As unprofessional as it may seem (and it is...) it came out fine...as the editing possibilities allowed by modern daws make this process quite simple. The most important thing is that your audio and your video run exactly at the same clock speed.

Hope this helps

[Sound Sorcerer]

A MOTU Midi-timepiece AV would read SMPTE & Word clock and also provides an ADAT sync port... Only problem running this way is that your HD24's would've to be the master and Logic the slave.
I think you're better off with what Gerax advised...

[Remoteness]

We were never able to get the MOTU Midi-timepiece AV to work with the Alesis HD24XR.

Each company blamed the other even though Alesis lists the MOTU Midi-timepiece AV as the device to use.

[Berrevd]

OK. Thanks a lot guys.

So the conclusion is that in all cases I should get WC derived from the BB signal and send that to both systems.
TC is nice to have, but not a must, and considering the problems with the HD24s and the ADAT sync I think I will leave at as it is and do the alignment manually.
Unprofessional, but doable and... cheap...

Thanks again for all the advice.

grtz,
B-)

[Remoteness]

We have found that the Brainstorm DCD-8 with VSG4 card is an excellent way to go.

We got one in as a demo and we don't want to give it back!

This is a serious box that (IMO) is second to none.

On the HD24XR SMPTE timecode front, the BRC (if you can find them on eBay) is your only solid way to handle TC.

[Sound Sorcerer]

Originally Posted by Remoteness

We were never able to get the MOTU Midi-timepiece AV to work with the Alesis HD24XR.

Each company blamed the other even though Alesis lists the MOTU Midi-timepiece AV as the device to use.

I've successfully slaved Nuendo to ADAT-XT & M20 decks on several occasions using a MTP AV, but as I mentioned before only using the decks as a master & computer as a slave, for dumping tapes into my DAW. I've never tried with a HD24XR.

[Remoteness]

Yeah, the HD24XRs do not like MOTU Midi Timepieces very much.

Hey, if anyone got it to work please let us know -- It would be a more elegant solution than lugging an old BRC around.

[huub]

I won't name names, but I know of one internationally working truck that always uses the internal sync of their super expensive digital console..
So they only use tc to timestamp their Bwavs (Wich, b.t.w. only stamps the beginning of the file.. It certainly doesn't hurt their business.. I wouldn't do it, personally, but it certainly is doable..
The thing is, in editing, the fcp or avid only reads the timestamp, so it knows where the file starts, but then the show is cut up in songs, and all syncing after that is manual (i'm no editor, but we have an editing department, and i've seen em do that)..
Even with out of sync wc, the drift is not going to be so much that you'll notice it within one song..

Just trying to keep it inexpensive for you