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How to fix a lav mic sync issue

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Michael Freedman
How to fix a lav mic sync issue
on May 10, 2015 at 8:10:03 am

Hello, I'm working with anywhere between 4-7 lavs in Avid MC 8.2.3 (Yosemite 10.10.1)

I am syncing by timecode but the waveforms of the audio tracks aren't exactly synced and inline in my timeline, they are less than a frame out. On playback everything sounds fine, however when I export to QT I am getting a weird echo effect with some of the clips on playback in QT Player 10.1 and 7.6

I think it is to do with the other lavs picking up the speaking actors line and because the waveforms are not exactly in sync it's causing the echo. However it is strange that in Avid I can't hear the echo.

I am exporting the timeline as H264/AAC / 29.97/48khz / keyframe every 29.97 - and playing back in QT 10.1 and 7.6

I don't believe the sound recordists are using a field recorder. Is there anything I can do inside Avid to stop this issue?

It's obviously quite distracting for the director when viewing his dailies



Michael F

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Michael Phillips
Re: How to fix a lav mic sync issue
on May 10, 2015 at 6:22:50 pm

Seems a bit strange that your exports are not sounding the same as in Media Composer unless track monitoring is not the same as with export. Try a mixdown first, export an compare and see if that is any closer.

Distance between each mike might pick up some fractional latency if it is picking up other actors voices, but the distance is usually 10'ish plus feet for that to become noticeable. Here is the timeline from a single mike (on camera) and the effect of distance on sync:

In your scenario, I am assuming lav on each going to a mixer of which each track is being recorded to camera or other type device? So the distance between each of mikes to each other might be causing a similar effect.

Something to try is PluralEyes from your Avid timeline. It may well adjust each track in sync to each other, but may not do that when less than 1 frame. But something to try with their 30 day free trial.

Here is my blog on using PluralEyes with Media Composer:


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