I ran into this yesterday while helping a voiceover actor troubleshoot his setup. He’s using GarageBand and an Apogee duet interface, but this applies to any interface you’d use with the program.
The problem is that GarageBand defaults to stereo INPUT. Even if you select one of their guitar or vocal presets it still sets your track up to record a left and right channel.
Why is that a problem you ask? You say you want your recordings to be of the highest most topmodern quality? You assume that means stereo?
Well yes, of course you want your MIX to be in stereo, and often times you’ll insert an effect which will turn your individual track’s OUTPUT to be stereo- but that still doesn’t change the fact that you’re usually recording a MONO source.
Your guitar (unless it’s being run through a stereo effects processer BEFORE the computer) is a mono output. Your voice coming out of your one mouth is a mono output. Your bass guitar, again a mono output.
So what’s the problem if your computer records it in stereo? Your one guitar or one voice will be all on the left or right channel, with the opposite channel being silent. You’ll see this by seeing what should be a pair of waveforms (for a true stereo source) as one waveform on top with just a straight line on the bottom.
What problems does this cause?
Your voice or guitar is stuck on one side of the mix, and no matter what you do it won’t come over!
Your computer’s processing power is cut in HALF for each track recorded like this. Think about it: twice the data is being processed! So the more you do this the more hiccups and disk too slow errors you get.
You use twice the hard drive space. Again, doubling up on that data really causes a problem!
How do you fix it?
Simply change the recording input from Stereo 1-2 to either Mono Input 1 or Mono Input 2.
It’s easy, your GarageBand will run a lot smoother!