Mono Recording--How to Specify Input Channel to Use (see below)

I want to make a mono recording from an analog source and then export to a WAV file.
I want the WAV file to have the same mono signal in both left and right channels.

I know how to tell Audacity I am making a mono (1 track) recording.
I don’t know how to export my mono signal so that identical signals are sent to the left and right channels of the WAV file. How can I do this?

I am using Audacity v 3.4.2.
Thank you!

Ok, got it, thanks.
Another question on recording in mono: after I set Channels to “1 (Mono)”, it appears that Audacity takes signal from both channels and merges it into the left channel. Is there any way to tell Audacity to take input only from 1 channel or the other, rather than merging the two? I assume there is some loss of quality when two channels are merged together, even if one channel is silent.

A true mono (one channel) recording will play through both speakers.

If you have a stereo recording with one silent channel you can Split Stereo Track which allows you to edit left & right independently. You can click the “X” to the left of the silent/flat waveform to delete it and you’ll be left with mono.

…You could copy one channel into the other after splitting, but the “dual mono” WAV will be twice the size of as the mono.

Virtually EVERYTHING, analog and digital, is mono-stereo compatible. You can play a mono file or a mono vinyl record on a stereo system and it will come-out of both speakers. Or you can play a stereo file on your mono phone speaker and the left & right channels will automatically mix. Same thing if you play a stereo record or cassette on a mono sound system… You hear the sound from both sides.

Audio CDs are always -2channels but most CD burning software will accept a mono file and automatically duplicate the data.

Depending on how you do it… Mixing is done by summation. If you sum with nothing, of course nothing changes. But you want to avoid clipping (distortion) so when you mix left & right the signals normally need to be cut in half. Sometimes that happens automatically, and sometimes not, and there is more than one way to mix/combine in Audacity. If you do a mono-to-stereo conversion, you might need to check the levels to confirm what’s happening. (Not a concern if you just kill the silent channel.)

Or sometimes the “silent channel” isn’t totally silent. Sometimes “analog noise” gets-into the digital recording.

Thank you for your reply.
I was actually asking a different question. Sorry, I was not clear–I’ll try again.
I have a mono analog source (from a reel-to-reel tape).
Step 1: I want to record it in Audacity as mono in a single channel.
Step 2: I export it from Audacity to a WAV or MP3.

My question is about step 1.

In step 1, the input from my analog source to my analog to digital converter is a single cable from the analog source–in other words, a single channel of sound. My analog to digital converter sends digital output to Audacity. The analog to digital converter puts out 2 channels to Audacity: one channel contains my signal, the other channel is silent.

Then I set Audacity to record in Mono.
I know that Audacity takes the two channels (one contains my signal and the other is silent), sums them together, then sends the sum to the single mono channel Audacity is creating.

I do not want this to happen. Rather, I want to tell Audacity to take only the one channel that contains my signal and place this channel on the one mono channel Audacity is creating. Is there any way to do this?

The reason I want to do this is to avoid loss of quality from summing the two channels. There is no need to sum the two channels as one is silent.

One possible work around would be to tell Audacity to record in stereo. Then in my Audacity project I would have 1 silent channel and 1 channel with my signal. Then when exporting to a WAV or MP3 file, I could use the “Custom Mapping Option” to kill the silent channel and send the signal channel to both channels of the WAV or MP3 file. Does this make sense and is this a correct way to get my mono signal to both channels of the final (WAV or MP3) file?

The easier way to kill the unwanted track is split stereo to mono, then delete the silent track …

kill unwanted silent channel

Hi Trebor,
Thank you for your reply.
Is your first suggestion the same technique I described in “One possible workaround”?
Would the end audio results of your two suggested procedures be identical? (It seems to me they would, but perhaps there is something I don’t understand about Audacity.) My goal is to get the most accurate conversion possible.

Yes, but custom mapping is unnecessarily complicated way to do it.
Whereas if the unwanted track is deleted [ x ] it’s gone. Guaranteed.

Maybe if you duplicate your mono track, you can pan one to the right and one to the left and export the mix. Hope that helps.

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