The mid-side recording technique for drums only requires two mics and can be a great way to capture a recording which can then be widened at the time of mixing and is also mono compatible.
For this technique, you will require an ordinary cardioid condenser mic and a figure-8 pattern condenser – your best bet is probably using a multi-pattern condenser mic that can change it’s polar pattern using a switch.
The ‘mid’ microphone is suspended above the drum kit pointing straight at the centre of the kit. We’re aiming for this mic to capture the kit directly, and it will be panned straight up the centre in our mix. The ‘side’ mic, which uses the figure-8 pickup pattern, will be positioned so that it is suspended above the kit with the end of the mic pointing straight down, and the sides of the mic oriented towards the left and right of the kit. This microphone isn’t picking up the kit directly at all, since in fact, the kit will be in the ‘null’ point of the mic’s pickup field. The idea is that it hears only reflected sound – the sound of your room.
At mix time, the level of the ‘mid’ mic can be balanced against the ‘sides’ mic. Increasing the level of the ‘sides’ will make the room sound bigger and wider, whilst reducing it focusses the sound to the centre. As I said above, the beauty of this technique is that you still have control over the width when you come to mixing. Plus, you’ve got a totally mono compatible recording.
Try it, you might like it!