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I have files recorded on a Zoom H4N, the files are stereo, lav recorded to left channel and and shotgun microphone recorded to the right channel.

Is there a program (ideally that works on a mac) for batch splitting these files? In the end it would be nice to have each stereo audio file split into two mono files.

In Pro Tools, it can be done easily, as I'm sure with other DAWs, but I have tons (gigs) of files, and a batch process would be ideal.


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Do you have Pro Tools?

Drag and Drop them all into a Pro Tools session's region bin and they will all of them will be converted - just takes the processing time.

After they are processed, in your audio files folder will be split mono files.

Just make sure your session is the same sample rate/bit depth, and let it do it's thing.

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So long as you are consistent in your setup i.e. the lav is always channel 1 and shotgun is always channel 2. I'd find this the cheapest and most straightforward way to go, assuming you already own PT. – Steve Urban May 5 '11 at 15:44

For the people that record location sound with Sound Devices recorders, many of us use a free program called Wave Agent. It not only allows us to split and combine WAV files in bulk, but allows us to edit metadata and create sound reports.

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You can use Sound Grinder.

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There are lots of apps that can do this. Have a look at SoundConvert (for OsX)

It can convert audiofiles in a looooooong list of formats, and can split your stereo files in pairs (and can do a few other things too).

Just drag a folder (or single file) and let the app do the conversion...

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@Dave Thanks this is the type of light weight program I was looking for, I can just drag and drop a folder right off of the zoom and drop it in to have the stereo files split into left and right channels. – knumbers Dec 13 '10 at 19:44

The free audio editor Audacity has a batch processing function which might be what you're looking for.

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I'm sure SoX can do this, but you'll have to figure out the right command. says:

For example, to extract the left channel give a command like this:

  sox foo.wav -c 1 foomono.wav avg -l
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+1 on the WaveAgent from SoundDevices suggestion. It holds a special place in my dock.

Also, one that hasn't been mentioned is AudioMove from one of the myriad brilliant minds at LCS (now owned by the also brilliant minds at Meyer Sound). It even works over a network. There's a clever little toggle switch in the upper right to split multi-track files.

(edit) Forgot to mention that AudioMove does batch processing quite well.

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You could also give AudioGate a try. It's a piece of software from Korg and used to just be available for the MR series of recorders but is now free. It's actually very good for converting. Go to

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