panning a mono file with chains?

Hi, I have a large set of short mono files that I’d like to transform into stereo files with a silent right channel, and re-export as .wav.
There seem to be two possibilities for doing this manually:
a) more steps: converting the file to a stereo file and then using some of the plugins (like pan, channel mixer, etc; these don’t work unless you’re starting with a stereo file)
b) simpler: you just use the left-right dial in the track control panel, and pull it over to the left, and then export the file, this turns it into exactly the kind of stereo file i’d like.

Now with ~900 files, I’m looking for a way to do this as a batch process, using chains.
As far as I can tell, chains don’t let you include selections in the track control panel, or general menus, but maybe I’m wrong?
I’d also be happy to go route a above is there was a way to automate the making stereo step

Any suggestions?

Thanks in advance!
I’m using 2.0.6 with OSX 10.8.5


Currently I don’t think there is any way to do that in a Chain.

It would be possible to do that with “SoX”, but that is a command line program and you would need to write your own batch script to tell SoX what to do. I don’t use Mac, so I’ve no idea how to do that with a Mac, but if you know anything about scripting, then it would probably not be very difficult to do. The manual for SoX is here:

It would be quite easy with the nyquist prompt, at least if you’re working with wave files.
However, I can’t test it right now since I use 2.0.7 alpha and the system.lsp file (which is needed for file import/export) is still not available on Windows.
Steve has perhaps the 2.06 version installed and can assist you.

Unfortunately not if you are working with mono wav files.
Nyquist is not (yet) able to change the number of channels in an Audacity track. That’s the one step of the job that we can’t yet do in a Chain.

I mean to do it within a loop over a directory and not with a chain command, using s-read and s-save/s-overwrite.

Can you explain what that problem is (in a new topic), Robert? The precompiled 2.1.0-alpha builds for Windows now include system.lsp, so do I take it you are self-compiling Audacity?


I’m referring to
The system.lsp isn’t missing anymore but it is (presumably) the Linux version for all platforms (Rev 13713).
It means that e.g. file-separator returns ‘/’ on Windows.
It’s rather something for Devel than this forum.
(by the way, does stereo to mono work in your alpha build?)

I’ve emailed the developers about the problem. It’s important that is fixed before release as it breaks several things (including the shipped “Sample Data Export”).

Thanks for mentioning it. No it fails to initialise on all platforms. I reported it on the -quality list.


Original Poster here. Just in case anyone’s curious, the way I ended up solving this was doing the stereo-to-mono as a batch in another program (using some linguistics software called Praat, which can interface with the statistics programming language R that’s just about the only language I know well, PraatR library for the curious:, and then using a chain do the panning in Audacity. Worked like a charm.

Not optimal in terms of number of clicks and program needed, but not a bad solution either.
Will be glad when audacity’s chains can do more things:)