So I have a basic audio interface (scarlet 2i2) and a shure sm57 microphone that uses an XLR cable. But when I screen record with quicktime it records to just one channel (the left channel) through my mic. Because my microphone is connected to just one of the XLR inputs on the interface. So it's just recording on that one channel (and there's no way to change it in quicktime), so when I play it back I can just hear it in one ear.

So I was wondering if I should buy some kind of splitter that basically converts my microphone into two inputs so that both channels are recorded simultaneously and then it'd be in stereo? online I saw it's called a "XLR Female to Dual XLR Male Y-Cable".

But wouldn't that degrade the sound quality of the mic or is it ok to do this?

p.s alternatively I could extract that audio from my recording and convert it via software from one channel into two channels. but I think I prefer the hardware solution because it's one less step.

Edit: just got this Y splitter cable and it works perfect on both my dynamic and condenser xlr mics.

Edit#2: found a software solution that converts it from one ear to two ears so don't need to use the y-splitter anymore. ffmpeg -i stereo.mov -codec:v copy -af pan="mono| c0=FL" mono.mov


3 Answers 3


Microphones are mono, not stereo. Just set your DAW to treat the 2i2's input where you've plugged in your mic as a mono input, and you'll hear the signal in mono in both ears instead of one half of a stereo input.

If you want to record in stereo, you'll need two mics or a compound microphone that's specifically stereo (many of which are two-headed). But interfaces like the 2i2 that support both 48V phantom power for mics and instrument/line inputs are typically used for recording a microphone in mono along with an instrument input, no need to waste an input on another mic.

Yes Y-splitters work and won't degrade the signal, if you decide that buying a hardware solution is preferable to flattening the audio track to dual mono with software.

  • but I'm not using a DAW. I'm using quicktime and it doesn't have that option, so it just records in one ear.
    – user34288
    Commented Nov 2, 2019 at 3:48
  • I don't have Quicktime and find it hard to believe it won't let you set a recording input to mono, but is there any reason you can't use some free recording software like Audacity, or Reaper or GarageBand? They'll give you a lot of options for editing and applying effects. Audacity is very simple and easy to use, and I personally use Reaper as my DAW as it's very powerful.
    – user63785
    Commented Nov 2, 2019 at 3:56
  • using quicktime cause I'm trying to record a screencast on my mac.
    – user34288
    Commented Nov 2, 2019 at 4:00
  • Okay, well to answer your question yes Y-splitters work and won't degrade the signal, if you decide that buying a hardware solution is preferable to flattening the audio track to dual mono with software. Strange that any recording software wouldn't be able to set a mic input to mono though, but there should also be OS level device settings you can change.
    – user63785
    Commented Nov 2, 2019 at 4:09
  • Perfect answer. However it is better to use an electrically powered splitter and not the ones which are internally just two wires connected in parallel. The plain ones can degrade the sound quality. Also, @foreyez, as others have suggested, it will be best to use a pepper audio recording software. For instance, you can install Audacity. Its a free Software and comes with most EQ and FX options.
    – user32717
    Commented Nov 3, 2019 at 8:59

A Y-splitter will work. Or it seems easy to post-process in GarageBand, as described here:

  • tnx yeah I saw that vid before I asked this, it's actually what inspired me to get a y-splitter because that whole process seemed so complicated. but I'm wondering if a y-splitter would make it so each channel will be twice as quiet since I split the original signal.. well I guess I'll find out.
    – user34288
    Commented Nov 2, 2019 at 16:30
  • No, low-impedence sources into high-impedence loads don't work like that.
    – Laurence
    Commented Nov 3, 2019 at 11:20

Microphone cables carry a balanced signal with a certain impedance that supresses noise by having induced voltages and currents cancel. A signal splitter will halve the impedance the microphone sees and will stop the current balance on each input to be automatically neutral.

Both of those changes are changes to the worse. Just tell your recording software that it is dealing with a mono signal.

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