To understand why we use stereo vs mono recordings of instruments, you have to visualize the instrument itself and the source of it's sound. Let's look at a few examples.

  • Solo wind/brass instrument - produces sound primarily from the bell of the instrument. Sound does not change whether the mic is on the left or right of the bell. Does not benefit from stereo micing.
  • Vocals - produces sound primarily from the mouth. Sound does not change whether the mic is on the left or right of the mouth. Does not benefit from stereo micing.
  • Guitar and other handheld string instruments - produces sound primarily from the sound hole, but some sound from the neck. May benefit from stereo micing, but effect is subtle.
  • Electric guitar - produces sound from the amplifier's speaker. Often there is only one speaker. Sometimes there are two or more speakers, but the same signal is fed to all speakers simultaneously - this does not benefit from stereo micing. Sometimes there are two speakers which are fed separate signals, or the guitarist uses more than one amplifier - this can benefit from stereo micing.
  • Piano and other acoustic keyboard instruments - produces sound from each string (or course of strings), where strings are laid out in a left-to-right fashion. Significantly benefits from stereo micing. Electric pianos typically have a mono output, but may have stereo effects added to them, so they may or may not benefit from stereo recording.
  • Drums and percussion - produces sound from the skin of each drum or surface of each cymbal. Each drum or cymbal produces monophonic sound, but usually drums/cymbals are laid out in a left-to-right fashion, which significantly benefits from stereo micing.
  • Other instrument types not listed - take a look and listen to the instrument. Do you think the sound would be any different if you were to stand on the left of the instrument vs the right?

Basically, most instruments do not benefit from having two microphones put in front of them, unless they are either very large sound sources or they are actually collections of multiple smaller instruments. Typically this means that most instruments are best recorded in mono.


Quote:
Should I be doing anything differently in my DAW when rendered RTs are stereo rather than mono? Does it matter at all that some are stereo?

That depends on how much space in the mix you want that instrument to use - space being from left to right. Lets use a stereo piano for example - if you want that instrument to take up a large space, you would want to keep the track in stereo to keep it as wide as possible. If you only want the piano in the background, you may want to make it mono and pan it some amount left or right. Let your ears be the guide - don't worry about what you see on your screen, because ultimately the listener is not going to be looking at that when they listen to your song.

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