8mm Forum: Sound Sync ?

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Posted by Brian Collins (Member # 761) on December 02, 2010, 12:15 PM:

On my super 8 machine, Bolex Sound 715, why does it take 10secs of actual film to play before the sound starts and when the film has ended it takes 10seconds for the sound to end, this is on home movies I am refering to. If I copy the film to hard drive and then move the sound track back 10seconds it does not lip sync with the picture. I take it that it is because of the length of film between the gate and the sound heads, if this is so then it means that home movie films are always silent for the first 10seconds, Am I correct?

Posted by Steve Klare (Member # 12) on December 02, 2010, 05:58 PM:

Brian,

Are you saying that with the ten second lag the sound is in Sync?

The gap between gate and heads is 18 frames: 1 second at 18 FPS and 3/4 Second at 24 FPS.

Posted by Brian Collins (Member # 761) on December 03, 2010, 06:19 AM:

Steve
One film was 10seconds and another is 7seconds and both are in lip-sync all the way through. most unusual I imagine. Could it be depending on what camera was used to capture the footage, I did notice they were useing a seperate mic on a lead but don't know if it was attached to the camera or a seperate recorder, the films have two sound tracks.

Posted by Steve Klare (Member # 12) on December 03, 2010, 08:11 AM:

OK, This is starting to make sense.

To me is seems like the sound was originally recorded on a seperate recorder and then synced up later. It's the only way I can think of to explain that long gap.

Years ago I had ideas of recording sound seperate system, getting the film striped and then recording the track on the stripe. By the time I understood all the complications of it (especially the extra equipment to lug around) it started to sound like too much work to be any kind of fun. (Supposed to be a hobby, after all.)

Lip-sync starts to imply scripts and actors of some kind and I can't imagine getting that level of cooperation out of most people I know.

(-Easier just to buy films!)

Posted by Maurizio Di Cintio (Member # 144) on December 04, 2010, 05:16 AM:

Have you tried to play it back on a different projector?

Posted by Brian Collins (Member # 761) on December 05, 2010, 04:06 PM:

Yes Maurizio and it is the same.

Posted by Joerg Polzfusz (Member # 602) on December 08, 2010, 03:39 AM:

quote:
The gap between gate and heads is 18 frames: 1 second at 18 FPS and 3/4 Second at 24 FPS.

The gap for Standard 8 is 54 frames. That's 3s at 18 fps and 2 1/4s at 24 fps. Some "dual gauge projectors" (Standard8 and Super8/Single8) are using this distance for both formats, e.g. some Heurtier-projectors. According to the manual, your projector is using the "18 frames gap" as defined for Super8. However the sound might have been recorded on such a "dual gauge projector".

A completely different idea: It looks like your projector has got a "fade"-option for the sound. When enabled it might reduce the volume long enough to make you think that there's no sound at the start.

Jörg

Posted by Brian Collins (Member # 761) on December 10, 2010, 05:47 AM:

Thanks Joerg for that information, We can always learn something on this site.

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