How Soundtrack Pro Handles Mono and Stereo Files

Posted on by Larry

[ This article was first published in the Jan, 2007, issue of
Larry’s Free Monthly Newsletter. Click here to subscribe. ]


This started with a nice letter from Peter Helenius, who writes:

First let me say that you do a great job for However, I came across one issue that you did not mention. When exporting a project from FCP to STP there is a big difference on how STP deals with mono clips.


If your FCP project is in Link mode (MODIFY/LINK) the mono clips are in one channel only. If your project is not link(ed) the mono tracks come in on two channels. This took a while to figure out.


The mono portions of my project would show as stereo clips in FCP allowing for left and right panning for effect. When using send to multi link project into STP there was only one channel displayed which did not allow me to pan to the other channel at all. It was not until I turned off the link feature in the FCP modify menu that I was able to play with the sound as I wished to.

Larry replies: Peter, you are right that STP does not handle mono clips the same as stereo clips. However, your understanding of what the Link function does and how STP handles these different clips is a bit off, so let me explain further.

FCP Newsletter Screen

What Modify > Link does is connect, or disconnect, the link between the audio and video of whatever synced clip, or clips, are selected. By default, a synched audio/video clip is linked.

FCP Newsletter Screen

This means that if you move the video without moving the audio, Final Cut will display a red flag indicating the clip is out of sync.

FCP Newsletter Screen

Note: To move clips back into sync, Control-click on the red flag of the clip that is out of sync and select Move into sync.


But, I digress…

Soundtrack Pro pays attention to the link status of a clip when it receives a clip sent from Final Cut:

FCP Newsletter Screen

This illustrates that a mono clip with no panning remains a mono clip.

FCP Newsletter Screen

This illustrates that a mono clip with panning is converted, during import to STP, into a stereo pair with the same audio on both tracks.

FCP Newsletter Screen

This illustrates two clips that were captured mono, but were then linked into a stereo pair are converted to two mono clips on two separate tracks.

FCP Newsletter Screen

This illustrates that only clips that were captured as stereo show up as a single stereo clip in Soundtrack Pro.

Thanks for writing. I enjoyed the chance to think this through a bit more clearly with you.


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One Response to How Soundtrack Pro Handles Mono and Stereo Files

  1. Kevin Austin says:

    Hello Larry Jordan & Co,

    I’m having an irritating problem with soundtrack pro I was hoping you could help me with.

    I’ve sent a finished edited sequence to Soundtrack Pro as a multi-track project and applied some noise removal to all the dialogue in the sequence.

    Now when I export the sequence back into Final Cut Pro the text in my sequence is magnified 4x and being lopped off at the left and right edges of the frame (I brought up the wire frame and tried resizing the text but it is literally lopped off at the edges).

    What on earth is happening here? The rest of the sequence including the sound alterations done in Soundtrack Pro are fine. The text in question is just FCP generated text over top of an animated H.264 graphic background and a .tiff file of a corporate logo in the same frame.

    I’m mystified. Any suggestions would be greatly appreciated. Thanks. Love your site.

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