How should I set up equipment for recording instrumental music?

Question

I am planning to record two pieces:

1. A cell piano duet
2. A cello, piano, guitar piece

I have a room available at my university which, I am told by a professional composer, has excellent acoustics for recording. So I have a room selected. I also have recording equipment I may need since my university has a large selection of microphones as well as a digital editing studio connected to the recording room.

List of microphones we have available

• Sennheiser ME66
• Sennheiser ME64
• Sennheiser MKE400
• Sennheiser Wireless ew100
• Shure SM81
• Shure SM58
• Audio-Technica AT4050
• Beyerdynamic M88 Dynamic Mic
• Electro-Voice 635A Dynamic Mic
• Samson T32 Wireless Mic
• Sony MS957
• Realistic Dynamic
• Victor Dynamic Mic
• PZM Microphone
• Tram
• Shotgun Blimp

Based on a bit of research, I am guessing the ones in bold are the ones I would use for recording.

However, I am unsure where to place the microphones.

One important criteria: I want the instruments to sometimes come into the foreground and sometimes fade into the background and I'm not sure how to do this. Therefore, if I only had one mic picking up all of the instruments, this wouldn't be possible. So clearly to meet this criteria, I will need individual mics to some extent so I can fade out instruments when I want to. If this were synthesizers, I could simply fade them in and out with volume controls.

MY QUESTIONS

1. Do I need a microphone for each instrument? If so, where do I place the microphones relative to the instrument?
2. Do I need a mic that isn't next to the instruments and records all of them at once? or will simply recording the instruments themselves be sufficient.

Also, if you could recommend a book where I can read more about the practicalities / logistics of recording, that would be fantastic.

Answer 1

If you have the chance to be able record a in a room with great acoustics, then I would recommend that you try to actually capture a lot of its acoustic character. Nothing sounds as full, intimate and natural as an acoustic instruments recording “like you are really in the room”.

I.e., I would definitely use at least not only close mics, but start out with a good stereo room-mic setup. There are a couple of options; more on these later.

That about “I want the instruments to sometimes come into the foreground and sometimes fade into the background” – you should check out whether that's really necessary. Piano (assuming a decent grand) and cello have a pretty vast dynamic range, and if the players are good they should be able to get the “fading” right at recording, without any electronic help. Of course they'll need to know how the dynamics are intended!
Even so, to be on the save side, it probably is a good idea to add supporting mics for the guitar and cello (piano probably will never have problems getting through). I would go with a single small-diphragm condenser each: for the cello pointing straight at the bridge from about 1.2 m distance, and for the guitar pointing 45° from the neck joint towards the sound hole. Both the ME64 and the SM81 should be fine here, alternatively you could try one of the shotguns for guitar and the M88 for cello. Or the AT4050 (which in fact is probably best for all positions you need...) set to cardoid.

But, again, I would focus my attention most on getting the best room sound possible. I would place that mic about 4 m away from all instruments.

The easiest option for you is to set up the MS957 and be done. That's a good mic for many situations, but it's not necessarily the most “musical choice”. Most stereo setups require a matched stereo pair of condenser mics, which you don't seem to have. One exception, that I like a lot, is M/S stereo. You can do that with the AT4050 in figure-eight mode and pointing perpendicular to the instruments, plus the SM81 or ME64 pointing at the piano. M/S offers excellent clarity in the center channel, while also giving pretty broad and well-controllable stereo depth. You'll need to apply a M/S stereo matrix encoder somewhere, this is nowadays easiest done in the DAW software.