Problems batch converting stereo to mono

Audacity is the only free tool I trust to sum properly to mono, and I have 123 wav files I need to process for some research. I tried the chain tool with stereotomono only at first and applied to the files in question, and although audacity seems to have undertaken all the processing no changes are evident in the files on disk. I added an exportwav step but, again, although the processing seemed to take place no files were exported, and I don’t seem to be able to pick where or at what sampling rate/resolution to export them anyway. Am I missing something here?

Are you trying to export the new work on top of your old work — with the same filenames? Until you get everything to work right, I would export to Some Place Else and then delete the old work later. If something goes wrong with the way you’re doing it now, you could end up with no files.

WAV files do not have custom characteristics like MP3. If you imported the work at 44100 chances are that’s how Audacity is going to export it. You can change that with the value in the lower-left of the audacity window while the show is on the timeline. You have to do a Custom Export to get any bit depth other than 16. Default Microsoft WAV isn’t going to do it. If you do a plain, manual export, the panel will tell you WAV has no options.

Did you do one complete, successful manual export on one file before you tried automating hundreds of files?


Have you read Edit Chains - Audacity Manual and Apply Chain which should clarify?

The original files are never overwritten. The exported files will be saved in a folder named “cleaned” in the same folder that the original files came from.

When applying a Chain to files, the export sample rate will be the same as the original file (there is no way to change sample rate while the Chain is running).

16-bit depth for WAV cannot be changed because there is no Chain command for exporting to “Other uncompressed files”.

Do you want to “vote” for Chains to be able to choose sample rate and export to other than 16-bit WAV?



I tried; same result.

Thanks for the helpful reply; so as I suspected there’s no need to have ExportWav at all if the chain’s applied to files. I did notice the “cleaned” folder but it’s still empty after running all the processing.


What made you think that? Without the ExportWAV command there will be no export, even if the Chain is applied to files.

Add the ExportWAV command at the end of your Chain.

We record “votes” for “Feature Requests” from users and bear that in mind (as just one factor) when deciding on new features to implement.

Without those feature improvements you will be stuck with exporting only 16-bit depth for WAV and only at the sample rate of the file you’re processing.


“Apply to Files…
[…]Each file will be imported into Audacity and processed, exported to the format you chose in the Chain, then the processed audio will be removed so as to clear the temporary disk space that had been used.” There’s no mention of needing to add Export to the chain when applying to files.

I did.

On the forum in some thread or some web voting platform? I don’t see the need for voting on something like this, it’s just an obvious improvement. I do wish bit depth settings were a bit more convenient in general, as with sampling rate, so I don’t have to go to preferences just to see how it’s set

It says in a big green/cyan box directly above that:

The selected Chain > must > include an “export” step or the processed audio will not be saved.

Audacity can’t do that for you because it does not know what format you want to export to.

Then I guess there is something you are doing wrong. Look for the “cleaned” folder in the folder where you selected the songs to process.

There is a Feature Requests Wiki page Missing features - Audacity Support where you could vote, but you need a Wiki account to vote. Typically we record the users’ votes ourselves.

The problem when applying a Chain to files is that there is no sample rate setting for the export, so Audacity will always export at whatever sample rate the original file had.

Unfortunately when this feature was brought in, the developers did not agree that sample rate and bit rate settings were obvious. So the more votes there are for those features, the more likely developers will consider a patch that implements it.

You’ve stated your wish very clearly above so I will count that as “votes” (not personally identifiable in any way).

If you are still stuck, please attach the text file for the Chain you are trying to use. The file is at
Documents and SettingsApplication DataAudacityChains on Windows 2000/XP or
UsersAppDataRoamingAudacity Chains on Windows Vista/Windows 7/Windows 8.

You may need to show hidden files and folders in order to see the Chains folder. Please see here for how to attach files:


I just said the cleaned folder was present but empty. I know I’m doing something wrong; that’s why I’m here. Chain attached.

Yes but you may not be looking for the correct “cleaned” folder, so I wanted to be sure you were doing that.

Sorry, but there is no chain attached. Please see here for how to attach files:


Yeah I realized that right after posting but had to wait for it to be approved before editing.
S2M.txt (27 Bytes)

Your Chain works fine for me in 2.0.6 release.

Perhaps the problem is that you never answered the questions in the pink panel at the top of the page. So make sure you have 2.0.6 from Audacity ® | Download for Windows and tell us what version of Windows you have.

Are the files long enough that you see them import and you see the export? What is the full path to such a file that you are trying to process, for example “C:My Songsvocals.wav”?


You’re right - I had meant to and thought I had. I definitely have the latest, on Windows 7. The full processing takes place and corresponding visual output is displayed. The files are named things like “01 i.wav” and “02 Thinkin Bout You.wav” all in the folder ‘G:research’

Are you definitely choosing “Apply to Files…” when you apply the Chain? If so, the exported files will be in “G:researchcleaned”.

If you are choosing “Apply to Current Project” then these are the rules for where the “cleaned” folder is:

  • If the audio in the project came from an imported file or files, the “cleaned” folder will be inside the directory from which the first file was imported. The original files are not altered.
  • Otherwise, a message prompt will indicate the location of the “cleaned” folder that will contain the exported file. The “cleaned” folder will be in the last location that the Chain process exported to. If the Chain process has never been used for export before, the “cleaned” folder will be in the location at which the File Export Dialog currently opens.

Those rules are described at Audacity Manual.