Have you noticed your Audacity recording volume is too quiet since the update to version 3.1? You are not alone! This is a problem for people with some interface units that have 2 mic inputs, such as the Focusrite Scarlett 2i2, the Steinberg UR12, the older M-Audio Mobile Pre, etc.
So you are using a really good microphone plugged into a recording interface that has 2 mic inputs, and it's plenty loud enough in headphones. It's even plenty loud for Zoom or in any other recording program. But for some reason, when you try to record in Audacity WITH THE EXACT SAME SETTINGS, you get a super quiet recording level. It might look something like this:
Just to give you an idea of what level this audio SHOULD have been, I used the EXACT SAME SETTINGS for a recording using Adobe Audition. I then imported the AA one into Audacity so you could see how different they are. See the pic below:
If you want the stats to compare, the Audacity version had an average level of -30.33 LUFS (Loudness Unit Full Scale). The Adobe Audition version's average level was -20.47 LUFS. Remember in digital audio, things are measured in negative numbers. and the closer to zero you get, the louder it is. So this is a 10 dB difference! That means Audacity is lowering the level of the incoming signal by 10 dB. That is a lot.
This was a mystery to me, and only started happening when I updated Audacity to version 3.1. I've heard similar stories from others who are using interfaces with 2 mic inputs. [UPDATE: A very similar problem has been happening in Camtasia software for years and I only now realized it as the same basic cause. The solutions and workarounds in this post work for both programs (and, I'm sure, any other program with this issue).
After many days of searching for causes, I found the cause. Audacity has a weird conversion thing it does when it sees a stereo signal coming in, AND you choose the option (in Audacity) to record in mono. There is a dropdown in Audacity's toolbar where you choose between "1 (Mono) Recording Channel," and "2 (Stereo) Recording Channels.
It makes total sense that if you are recording a single voice into a single microphone plugged into a single microphone input on a recording interface, you'd choose "Mono." Because, well, you're recording a mono thing!
If you thought that - like I did - you'd be wrong. First of all, this isn't ALL Audacity's fault. It turns out that most 2-input interface units send all audio to the computer as stereo signals by default - regardless of how many mics you have plugged in. That means Audacity sees a stereo signal, even when you THINK you're sending it a mono signal. That is the first issue.
But then Audacity does something odd. Since you have chosen "1 (Mono)" in the Audacity toolbar, it thinks you are recording a mono signal. But since it is getting a stereo signal from the Scarlett interface, it sees a discrepancy. And it thinks it needs to reduce the input level...by a LOT.
I've read that it's trying to cut it in half. But since my result was a one-third reduction (-30 dB vs -20 dB), I'm not sure that is correct. But either way, the result is a much-reduced level. And that leads to the small, hard-to-hear waveform in the Audacity track.
And BTW, this is NOT just an Audacity thing. I've been having trouble with Camtasia (screen recording software) recording only on the left side for years! But I didn't realize this was the same problem. Some software programs just want to see stereo input if they are hooked up a 2-channel/2-mic input interface.
Let's start with what NOT to do.
Now that I know what I should not do, what are the things I should do to solve the problem?
There is a way to actually record at the proper level. But it involves sort of tricking Audacity. Before you record, tell Audacity you're recording a stereo signal. Technically you are, because the interface is sending a stereo signal even for a single voice. So change the selection in the dropdown from "1 (Mono) Recording Channel" to 2 (Stereo) Recording Channels.
This will result in a 2-channel "stereo" track. But all the audio will be on one channel. See the picture below:
This was with the microphone plugged into "Input 1" on the interface, which is the one on the left. If you plug the mic into Input 2, this flips. The audio would be on the bottom (right channel), with silence on the top part of the track (left channel).
So once you've got the 2-channel/stereo track recorded in Audacity, the channel with the audio on it will be full volume. Yay! That's the first part of the workaround. If you leave it like this, you'll only hear the audio out of one speaker or the other.
So the second part of the workaround is to split the stereo track into two mono tracks. This is super easy. Just click on the dropdown menu in the stereo track's control panel on the left where it says "Audio Track."
Then click on "Split Stereo To Mono."
This will result in two mono files. One will have the audio. The other will be blank.
The final step in the workaround is to simply delete the blank track by clicking on the "X" in the upper left corner of the track control panel on the left. this will leave you with a single mono track with your voice (or whatever you were recording) at the proper level. This workaround may have sounded complex. But in reality, it takes like 10 seconds to do it.
If you don't want to go through the hassle of splitting and deleting every track every time you record, worry not. There is a fix.
In Windows (where this problem seems to be most prominent), navigate your way to "Manage Audio Devices." Probably the fastest way to do get there is to right-click on the speaker icon in the far right of the taskbar. Select "Sounds." Then in the panel that shows up, click on the Recording Tab.
Once there, click on your interface, which should be the default (green check mark). Then click on "Properties." In the Properties panel, click on the Advanced tab. You'll see a dropdown menu that will probably have "2 channel, 24 bit, 44100 (or 48000) Hz (Studio Quality)" selected as the default. Change that to "1 channel, 24 bit, 44100 (or 48000) Hz (Studio Quality)." Hit "Apply."
Once that is done, go back to Audacity and make a new recording. Make sure to select "1 (mono) recording channel" before you do. And now you'll get the full volume/level of audio in your mono recordings!
Of course if you DO want to record in stereo at some point, you'll need to reset the Windows Sound setting back to 2 channels.
One problem I know of with the "fix" above is with the Steinberg UR12. For some reason, Windows will not let you change from "2 channel..." to "1 channel." I don't know why that is. But if I figure it out, I will update this post.
[UPDATE] I DID find another solution that will work for Steinberg and any other interface with 2 microphone inputs. It's an XLR mic cable splitter. I bought the one pictured below for 10 bucks from Amazon - Cable Matters XLR Splitter Cable, Female to 2 Male XLR Y Cable:
Just plug your mic cable into the male end of this splitter. Then plug both female ends into your 2-channel, 2-mic input interface (one for each mic input). This solves the problem without needing to go into Windows Sound settings and changing channel output. And it also means you don't have to switch the setting back to 2 channels when you DO want to record in stereo.
I hope that helps you cure any headaches or bouts of stress this issue may have caused you when recording a mono vocal in Audacity 3.1.