Hi! I have an ongoing problem with the following: We record interviews for our podcast using a tascam dr-40. We record in WAV and in stereo and use two high quality external mics. When we listen to the interview in stereo, it sounds perfect–but when we convert the stereo file to a mono file, the person whose mic was plugged into the R on the tascam (I’m assuming the R stands for right channel?), sounds significantly quieter than the person whose mic was plugged into the L on the tascam. Anyone have any thoughts?
How are you doing that?
We’ve tried both using the ‘tracks’ dropdown menu and sellecting ‘create mono file’ and also splitting the tracks and then deleting the bottom channel. The same thing happens both ways.
You can get that if you have a wiring error or some other physical/electrical problem with one microphone. It’s a big red flag when something works just fine in stereo and continues as long as you never go to mono.
I’m guessing when you use both microphones normally, they’re never very far apart? What kinds of microphones? Are they both XLR type and do they match? Can you figure out which is which without looking at the serial numbers or the pieces of colored electrical tape you put on them to identify them?
Just as a quick test try this: Make a brief recording with both microphones jammed against each other. No spacing at all. What happens to the stereo show and what happens to the mono show? Just going to mono (Tracks > Stereo Track to Mono) should give you a nearly doubling in volume if everything is OK. I’m guessing yours won’t do that. Your show may vanish.
Koz
The show may not double in volume, but it should not change. I think “Stereo Tracks to Mono” compensates for the normal increase in volume effect. But still. Let us know what happens.
Koz
What happens if you use the track drop-down menu and use “Split Stereo to Mono” (without deleting either track)?
If I do that, is it still considered a mono file?
Are you using Audacity in other than English language? If you have Tracks > Create Mono File when you are running in English, we did not make that Audacity version.
Gale
That shouldn’t happen. How are you converting stereo to mono?
If you use Tracks → Stereo Track to Mono, that shouldn’t happen… It doesn’t happen to me! 
Of course, before mixing you can adjust the left & right tracks independently. So, if there’s anything “funny” going-on, you should be able to word-around it. (You might have to split the let & right channels into two separate tracks first.)
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Some information that might be helpful, or it might be confusing—
Mixing is done by summation (addition). Analog mixers are built-around a summing amplifier.
That means if your left or right track is normalized (maximized) you can get clipping (distortion) if they are simply summed together. The Stereo Track to Mono function takes care of that automatically by cutting the volume of both channels in half before mixing to mono. (So mathematically, you are averaging the two files.)
But since the computer (or MP3 player, etc.) plays mono tracks through both speakers, the single mono file gets doubled again and there is no loss of volume.
What happened when you did that too-close double microphone test?
Koz
Of course. If you export the track and don’t pan it, it will be a mono file. It will play equally in both left and right channel of a stereo player.
Gale
I’ve merged your duplicate topic into this one. Please don’t confuse everyone by posting the same topic twice. Stay in this topic.
Please try what Koz suggested:
Gale