Weird Audio issue in QT Playback

[Dwain Barrick]

Hey guys I'm hoping that someone may have some insight on this. We are recording sound with the R1. We have done this before but I have never seen what's happening today.

The camera levels are reading fine, I'm sending signal from the Sound Mixer to Channel 1 and 2. We can playback takes on the camera and hear great Audio. I remove the drive and connect to my 8 core Intel Back-Up/Transcode system. The R3D files will now play with clean and loud Audio in RedCine-X and RedRocket-X. But the Proxy files have very low and terrible audio.

After some messing around I ended up going into the QT Movie property settings / sound track tab / audio setting tab and changing the channel 1 and 2 assignment from mono to right and left.

Bingo Clean and great sound in QT, FCP and Clipfinder.

Does anyone know how to fix this.

Is there a setting on the R1 to combine channel 1 and 2 as stereo as opposed to mono?

Does this happen during the QT Proxy writing stage?

Is there a batch process to change all QT files rather than adjusting them individually?

Any input would be helpful.

BTW... I'm using QT 7.6.4
firmware: 20.1.3

Thanks in advance

Dwain

[Brian Ferguson]

It sort of seems like phase cancellation. Is the audio similar on both tracks? Or is it total separate signals as in different mics?

[Michael Romano]

I've had this issue with XDCAM EX MOV files before, solution was to pan L+R in FCP when editing. Stupid! AFAIK it has something to do with QT. The actual audio was not affected, just panned together. You could try rebuilding proxies with REDAlert or Clipfinder and see if that helps.

[Dwain Barrick]

Did the proxy rebuild. Audio Channels 1 and 2 are identical. Easiest fix was to disable channel 2 and only record mono to channel 1.

I will explore this more on my next sound job. I work primarily in a table top/product commercial house.

Thanks for the replys.

[Jason H]

Hi,

I have had this happen on a few of my shoots with the Red. I cant seem to figure it out but it's for sure a phase cancellation thing.

So the edit goes smoothly I have the audio guy at the start of the day feed audio to the camera and then check the proxies. If this is happening I have the audio guy just pan his audio a HAIR! to the left or right. All it takes is a hair! Then it's fine for audio in post. If you forget to do this and you get to the edit then the "pan L+R in FCP when editing" should do the trick. Wish I knew a better way to solve this problem but one of these 2 work.

[Gareth]

This saved me big time tonight... about to hand over media to client at first light. Thanks Dwain.

Cheers,
Gareth
Red1503