The banjo – this bizarre mutation of a guitar and a snare drum – can be a difficult instrument to record. The main challenge is to find a balance between the very attacky but thumpy sound audible near the center of the head, and the rest of the instrument’s sonic components, which – because of its complex harmonic structure – range from mid lows fundamentals to the top end side of the frequency spectrum.
Condenser or dynamic microphones are commonly used for close miking the banjo, but this is an instrument that can shine when at least one mic (normally a large condenser one) is placed a little further from the source – which is obviously something you can do only if you are recording it separately from the other instruments.
Try placing the close mic 6-12” away, aiming at the center of the head; if the attack is too pronounced, try moving the mic slightly towards the outer edge, towards the bridge and south of the strings, and/or experimenting with the mic’s angle. Different playing styles call for different techniques – if the player is using a pick or his nails, you may not want to go for the “full center” position, which may instead work better with a more gentle style.
Also, always bear in mind that dynamic mics are less sensitive to attack than condensers, and that, as always, the best recordings are tailored to the song context they fit in. – PDG