Take the 2-minute tour ×
Sound Design Stack Exchange is a question and answer site for sound engineers, producers, editors, and enthusiasts. It's 100% free, no registration required.

So the editor of this period drama says to me last week, the sync is out, and also commented that the 2nd unit recordist was as much as 5 frames out of sync.... now first of all let's says there's a 2 frame offset.. that still leaves 3 frames adrift.

I use the ambient lockit boxes on arri d21 cams, the master clock however is a ambient acc501... so I tune the lockit boxes to the 501.... half way thorugh the day I re-jam and at most the difference is around 0.04 - 0.25 of a frame out.

My mixer's box is a denecke and I jam this too, however it does not have a timecode out so I cannot check the diffence.

So with such tight sync between all devices, basiclly less than a frame how is it possible that the editors, bless them, are saying the sync is out by more than 3 frames in some cases?

Later on they told us, doesn't matter if it's out, it's out.... I wonder do they really know what timecode is and are they syncing it in post correctly?

I use time of day free run, 25fr, 48khz non dp.

I wonder if the problem could be with the mixer's fostex recorder as this is the only mixer to have a setting where you set the frequency to 48048 but it gets stamped at 48k, making the playback of the recorded audio 0.1% slower?

The 2nd unit mixer uses the same Fostex dv824

Any comments?

Sharpy

share|improve this question
add comment

1 Answer

Just to clarify: Is the offset consistent or does the sync drift more and more over time? In my (admittedly limited) experience, consistent timecode offsets of 1-2 frames even with top-notch kit isn't uncommon...but it's pretty easy to fix. Drifting sync over time could absolutely signify a mismatch in sample rate that you yourself diagnosed, or someone's sync box or internal clock not set to match drop vs. non-drop. How much post will complain or be willing to fix it depends on how consistent the problems are - if it's all over the place, they're right to have conniption fits.

Colin's got a lot of experience doing production audio, he might be able to chime in with more knowledge.

share|improve this answer
    
Well offset wont drift more because its an option so once set, its set. so Fostex by defualt have a 2 frame offset I forget the reasonng behind it. But as for the drift outside of the offset, according to the acc501 in a whole day the drift is never more tahn 0.25 of a frame. As I mentioned i dont jsut jam I tune them to within 2ppm. So in a day 0.25 drift at most... so I cannot figure how the editors are getting upt to 5 full frame drift. Unless the recorder on the arri is a bit pathetic... but then its being controlld by a lockit box so should be tight. –  Sharpy May 2 '10 at 18:04
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.