Mono vs Stereo problems.

[Chris Borjis]

Final Cut sums the audio.

you have to load the mixer window and select the timeline
then pan left to left and right to right if your doing mono.

otherwise it mixes them by default.

and if you have a faulty mic connector, you will hear
the audio when digitizing but the summing on playback
will cancel each side out so you hear nothing.

[Kevin Reiner]

Thanks Chris,

That did the trick. My only question now is – why is that the default? I can’t think of a benefit to having mono channels mixed by default. I’m just going to bring everything in stereo and not worry about it anymore.

Thanks again,
Kevin

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[Rafael Amador]

[Kevin Reiner] ” why is that the default?”
In the beginning the natural output from FC was Print to Video.
With the stereo output you avoid the need of mixing later on.
rafael

http://www.nagavideo.com

[Chris Borjis]

it was set up that way to make it easier for folks
to deal with it.

it becomes a problem (as you have experienced) though
for those of us that need it done differently.

the pan right left also only occurs per clip.
I’m pretty sure doing a select all will fix
that, but once it didn’t so double check that
each new cut doesn’t revert the mixer to center.

if you ever record on a camcorder with an xlr to
mini-stereo (headphone) adapter, you will hear
the audio on capture, but on playback they
will cancel each other out resulting in no audio.

you must pan those left and right to fix this.

[Mark Suszko]

That’s because of phase cancellation, the waves are exactly opposite each other and when summed you get nothing or barely anything. If one track gets offset by one frame, you’ll likely notice the audio suddenly come back full force: that’s the proof it was being phase-cancelled. There’s probably a tool somewhere in FCP or Soundtrack to fix that, but I don’t yet know where it is. Somebody here know?

[Michael Gissing]

If I understand this post at all, you are saying that when you captured as separate mono channels that the signal was mixed on capture? That makes no sense unless you were summing to mono externally before going into FCP. Of course you don’t want to do that.

If however your sound is cancelling when you pan the files to centre, rather than left/ right, then you are telling me that you have a serious phase problem with your original camera footage. You won’t fix that by just panning FCP after capture. If that is what is happening, then you need to sort your mic cables or perhaps your edit room monitor phase.

[Chris Borjis]

[Mark Suszko] “That’s because of phase cancellation,”

yes, exactly.

and some mic’s and the xlr to mini-headphone adapters cause it.

[Kevin Franzen]

It there is a phase issue, open the audio in a sound editor, i.e. soundtrack, or ProTools then flip the phase on one of the tracks. A sign for phase is an O with a / through it. It is always better to work with mono tracks and mix the two signals together to create a stereo effect. If the audio is panned, listen to the audio tracks through headphones and the two mics will sound different.