First: there is no joy in birdtown, my instruments (and electronics and backpack) are still lost. See here for details, if you haven’t.
But that aside: I’ve posted a couple of pics recently about mic setups – I’ve been doing a lot of recording of other people lately, and will be doing more, both for my own projects and others – so I thought I’d talk about them.
First, you should know that there are at least as many schools of micing as there are possible combinations of microphones. On one end, there are old-school extremists who insist you should mic an entire band or orchestra – mostly orchestra, this is almost entirely a classical thing tho’ you occasionally see it in jazz – with exactly two microphones, because you have two ears. The intent is to recreate the listening experience.
In that view, the main job is finding the right hall in which to record, and the proper setup of the band. And while I see what they’re saying, I also think that’s kind of nuts… except some amazing recordings have been made that way, so what can y’do?
At the other end are the people who want to mic every individual performer three or four different ways at the same time. I… don’t get that, either. You need to stay out of performers’ faces. I hate being tied down to mics, as a performer, and…

YES IT IS BACK ON WHAT IS WRONG WITH YOU SOUNDBOARD
…yeah. No. Most people are in between those extremes, of course, tho’ as mics have become cheaper, and with the switch to digital, I’m personally seeing less of “less is more” and more of “No, more is more.”
If you’re multitracking, the arguments start about whether instruments should have exactly one microphone (because there is one instrument) or two or many (because there are many points from which sound emerges). That argument hasn’t budged, as far as I can tell.
And those are decisions made before you even decide how to do whatever you’ve decided to do.
Personally, I’m too new at this to have a coherent philosophy. But I do have a method: I get inappropriately close to peoples’ instruments and listen for parts that sound cool. Then I figure out which mics I have that I think would do best at capturing those sounds, stick mics there, and try it.
So, some examples! Let’s start with a guitar. This is Mickey Phoenix from Leannan Sidhe:

AKG Perception 200 large-can condenser; Sony ECM-957 small-can condenser
The Perception has kind of a bad rap out there right now, and prices reflect that. It’s well-regarded for certain purposes (drums, female vocals) but you can find a distinct lack of fondness for its musicality.
And I have to say I do not know why. I’m having it do a good job not just on female vocals (as generally agreed) but a lovely job in getting low-end resonance out of acoustic stringed instruments of all sorts.
That’s what it’s doing in a few of these photos. On Mickey’s guitar, above, it holds the instrument’s “sweet spot” really well, nicely grabbing all those low tones and harmonics – things my other mics are not going to grab as well. Meanwhile, the Sony – which has weaknesses but is really good at transient sounds – is aimed right at the fingers, getting all those little “this is an organic instrument” finger and string sounds – and high-harmonics – that give acoustic guitar recordings life.
Mickey has been quite fond of the recordings we’ve been getting this way. He says it sounds like the guitar does to him, which he doesn’t usually hear in recordings. As a zouk player, I empathise with that.
Here’s Jeri-Lynn Cornish on Cello:

AKG Perception 200 large-can condenser; Sony ECM-957 small-can condenser;
small custom interface circuit mostly because reasons
Same two mics again, similar arrangement, but arrived at differently. I tried the Nova first here, as the mic closest to the U87 that I own, and… it just wasn’t right. It lacked the warmth I expect out of cello – and, honestly, while people have realised exactly how good a cheap mic the Novas are (and used prices reflect that, too), it’s not a very warm microphone.
So out popped the AKG again, and Jeri-Lynn liked that; it sounded like she expected recordings to sound. And that’s good, but I could hear something was missing, even if I couldn’t entirely find it. Not at first, anyway; I knew something wasn’t there, but didn’t know what. Whatever it was, it just wasn’t available to be picked up where I had the AKG, so I knew we were going to need another mic again.
Then she started playing a little snippet that I recognised as Bach, and specifically, that made me think of this performance by Yo-Yo Ma of Prelude, Cello Suite No. 1 in G Major – particularly the first 15 seconds.
Yes, I know it from Master and Commander, that’s how I found the video. That movie was awesome, deal with it. XD
That memory comparison told me what kind of tones I was missing. I didn’t even really hear it in the room, so I went looking for it, and when I got my ear in a position to hear what tones were bouncing up off the bridge of the cello, I found it.
I added the Sony first because I’m fond of heterogeneous microphoning, and because, well, this was calling out for a small-can cap. My Oktava 012 isn’t here yet – it should arrive today – and I rather think I’ll be using it more instead of the Sony in future. But for now, the Sony does well enough as a stand-in.
Immediately, you could hear the cello come to life in the recordings. The cello is often compared to the human voice, as a living, almost vocal instrument; part of that is the way it almost seems to breathe. With only the AKG, that sense of breath wasn’t there.
Getting the bounces off the bridge and bringing them up a bit in the mix put it back. Everyone heard it and understood what I’d been seeking.
(This was for a live-in-studio recording; if you want to hear it, it’s streamable here. These are virtually raw recordings; the only seasoning is in second vocals, there’s nothing at all added on the cello. The stream will be 128k mp3, which loses subtlety, but gives you the idea. If you want higher-quality, you can download it. ^_^)
Finally, I posted this picture a couple of weeks ago, but without much explanation; Ellen Eades, of a bunch of different groups, on hammer dulcimer:

ALL THE MICROPHONES
This is the largest number of microphones I’ve ever used on a single instrument. The hammer dulcimer is technically a percussion instrument, so acting on indirect advice from Ellen’s previous album’s engineer, I decided to treat it like one and immersive-mic it like a drum kit. On the Free Court of Seattle soundtrack album, I want it to sound like this thing is all around you, and in these test recordings, it does.
The AKG perception 200 is on bass bar. All the lowest notes use that as the bridge, so the low tones are heaviest there. An M-Audio Nova on treble bar, to pick up all the high harmonics. Both mics get a lot of both, but the emphasis changes in each ear, because AKG is one ear, and Nova is the other. This means you can hear the tones moving subtly around you as the notes go up and down in pitch. You can also hear the hammers moving back and forth across the strings, just a little.
To level it out and get a general comprehensive feel of instrument, you have the small-can cap Sony again, overhead, like a drumkit overhead mic. That’s mixed to centre, to link the sides, and potted pretty far down. It’s filler sound that ties the bars together.
But I still wasn’t getting enough of the low harmonics I knew the instrument could put out, so I threw another AKG down at the very bottom of the bass bar, at one of the instrument’s sound holes, and mixed that back to centre. And they popped right in. A nice, immersive, dimensional recording. (And I’m not looking to swap out the 957 here; it did a fine job and there’s no need to mess with what works.)
So, that’s how I do this so far. I wouldn’t use two mics where one would do, and I certainly wouldn’t use four where two would do, but, well, I want it to sound right. There are downsides to multimicing instruments – not just noise, look up “phase cancellation” if you’re curious – and you have to work to avoid those. But it can also pull in a lot of great sounds.