When I mic a piano, I use omnidirectional mics. (Neumann KM56) and place them in the middle of the keyboards. The first mic is placed closer to the bass strings, the second mic is towards the higher strings. You may have to put some sponge around the mic stand to absorb the vibrations after closing the lid but close the lid totally. This gives me a very present piano sound which is not muddy – usually associated with cardioid microphones. When the lid is closed, it helps me keep the leakage (incoming leakage from other instruments) down to a minimum and still allows me to get a full ,present piano sound. If the piano has soft-actioned hammers, place mics closer to hammers; if the piano has a hard-actioned hammers, place mics closer to the hammers; if the piano has a hard-actioned hammer response, place the mics further away from the hammers.
Placement of mics should be done with individual taste in mind and with regards to how the piano actually sounds.
George Semkiw – producer/engineer (Lou Reed, Harry Belafonte, Johnnie Lovesin and The Sattalites).