audio sync question

E

earthling74

New member
Hi all. This is my first post and I had a question about syncing audio to picture. I am shooting a live musical performance and I have some good mics but I don't have a wireless system. What I want to do is be able to use the mics but not be encumbered by audio cables attached to my camera. I was wondering if I plug the mics into a mixer that was going to a standard cassette deck, digitized the audio from that cassette then import it into my sequence will there be any sync problems? If this isn't a great way to do it does anyone have any suggestions? My mics are the Samson CO2 stereo pair and a Shure KSM32.
 
Would you care to elaborate on what type of musical performance you're doing?
Sounds like you have some nice microphones, but since we don't know what you're recording,
it's a little difficult to offer relevant suggestions. Does this make sense?

Related to the pressing issue of recording to cassette tape and syncing in post. For discussion,
I'll assume you mean analog tape.. There is no way in the world it will keep time the same as
the video camera. They will most certainly lose sync after a few minutes. It would be a wreck!

There are other alternatives like digital tape, with its' own host of digitizing woes to deal with
if you don't have the proper tools. (I wouldn't know if you do or not) or direct to hard drive.

Syncing is almost unmasterable. You definitely need a reference, like a clap board, for example.
Probably the best solution in any case would be to record directly to the camera. The slight
inconvenience you may experience on location through reduced mobility more than outweighs
the mess of trying to sync analog tape to miniDV. Would you be willing to believe me on that?

Hope this helps.
 
Don't use analog...you'll really be disappointed, synced or no.

So..assuming you can get your hands on a digital deck to record... A clapboard would be nice, but if you're zipping all around the place catch-as-catch-can, it might be impractical.

My suggestion: record off-camera on a digital deck AND use the built-in camera mics. Then, in post, lay the off-camera track right below the on-camera track and sync those up. Just scrub back and forth on the off-camera track until you can't hear any delay/echo. Then, once you are satisfied they are synced, remove (or move & disable) the on-camera track.

That will get the audio synced. Ah...but if you're filming quite aways away from the source, you may have to tweak a little due to some delay. If there are any obvious percussive sounds (a drummer, for instance), you'll still have to resync so the beat shows up on the beat. :-)

Dan
 
The only issue with using even an unjammed digital recorder is your sync will drift after a short time (anywhere from 5 to 20 minutes). While this is not a problem with narrative material with less then 5 minute takes, a music performance can go an hour or longer (depending on what type of musical performance we are talking here).

If there are breaks in the music you can use the audience clapping as time to re-sync.

To find out what sort of drift you are looking at. Shoot some test footage with the camera and digital audio recorder. Use a slate at the start and end of roll. Shoot about 20 minutes of footage. Once you get in into your NLE, sync up at the head slate and then move to the tail and see how far off the sync is there. That is your drift.

Good luck
 
Jut to restate what wabbit said, regardless of what other deck you record sound on, it will not stay in sync for very long. Without the captain motors of the cameras/decks synced through crystal sync (black burst, etc) each motor will drift along at its own speed making your edit a nightmare.
 
Yeah, there is no way that analog cassette will sync for more than a few seconds. I have had very good success with digital recorders though (DAT and Mini Discs).I have had MDs maintain frame accurate sync for over 20 minutes, but I would not use MDs to record music.

Try to get a digital recorder and as GenJerDan suggest record with your camera mic for a sync reference. I would also suggest that you get a good bit of B-roll of the audience or what ever so that you will have something to cut to if you have to readjust sync during a performance. Make sure that your B-roll footage does not have actions that would require accompanying audio (clapping, laughing, sing along, ect.). What ever audio system you come up with, test it before the show to avoid surprises.

Good luck.
 
Thanks for the input everyone. It looks like the best idea is to give up some mobility and go straight to the camera. The main concern of my client is the sound anyway. Thanks again to all!
 
Hey earthling74,

We recorded a concert about a month ago faced with the same basic issues as you described. We ended up recording the audio into pro tools by taking multiple submixed feeds strait from the front of house board.

We used 2 DVX100a's (plus a couple of stationary VX2100 cameras mainly for cutaways). We synced the pro tools mix to the camera audio and it worked out fine.
I think it really helped the visual story because the audio sounds very good.
 
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