Originally Posted by michaeldangelo
The easiest option is to get a pre-amp with as many channels as you need, and you can mix the mic's on the pre-amp and send that signal to the Powerbook as one stereo channel so you can mass mix the whole kit that way and add effects through whatever software you're using.
I think you'd need more than just a preamp outboard if you're looking for any serious quality with a large number of microphones. You'd really want a mixer with as many channels as you need for the microphones plus decent EQ on each channel - probably with at least a three-band with sweepable mids. Ideally you should route to compression as well, because you will want different settings on different microphones.
If you present a stereo mix to the computer there's very serious limits on what you can do to it afterwards. For example, it's quite nice to be able to give a bit of punch to a kick by putting in a highpass filter to take out the bottom octave (extra energy in the sound for no real audible effect) plus boosting the fundemental "Oomph" of the kick a bit. Then it's quite nice to notch out some of the boxy stuff around 800, plus boost the beater impact sound a little. But for a snare you'd want to approach things very differently, and on a stereo mix you don't have that ability to target individual EQ and compression settings to different drums. Reverb is usually alright on a stereo mix because you can restrict the frequency range so it doesn't muddy up your bassdrum too much, but unless you want to get seriously clever with multiband compression then you lose a lot of mixing flexibility by going to stereo before you've had an opportunity to do anything detailed.
Also by recording in stereo from 6-8 microphones you're making mixing decisions before you've been able to hear the performance, which can result in ruined takes because you realise the balance is just plain wrong and you can't fix it.
I'd really favour trying to find even a slightly lower quality way of getting all eight channels recorded separately into the computer rather than worrying about the quality of your preamp when you're going to kill a vast amount of your control by throwing away independent microphone channels before you even record. If there's a bit of noise or a less than perfect communication of the signal I'd suggest it is easier to clean that up with modern digital effects than it is to try to get a good drum sound from a muddy stereo mix.