Choose adequate microphones to record your baby grand piano. Condenser microphones are usually preferred for this task because of their ability to capture a piano’s wide frequency range. Dynamic microphones tend to be less responsive to the high frequencies generated by pianos and also blur piano transients. Popular condenser microphones for this task include, but are not limited to, the AKG C12, Neumann U87 and AKG C414.
Make note of the polar pattern of your microphones when selecting them. Some microphones have multiple, selectable polar patterns while others have a single, fixed polar pattern. The omnidirectional pattern is often used for recording piano at close distances because of its ability to capture sound from all angles. This prevents a given section of the piano from being highlighted, as the cardioid pattern tends to do. Omnidirectional microphones also tend to have a flatter frequency response with more realistic low end, while cardioid microphones can overemphasize the bass when close microphone placements are used because of the proximity effect.
Open the lid of your baby grand piano.
Utilize a spaced stereo pair of microphones inside the piano for a modern sound. Place one microphone over the high strings and one over the low strings to capture a general balance of the piano, about 8 to 10 inches above the strings. Space the microphones farther out from each other for a wider image of the piano. Space the microphones closer to one another for a more narrow stereo image. Place the microphones closer to the piano strings for a more direct sound with more attack or move the microphones farther away from the strings for a sound with less attack and more room. Move the microphones to achieve a balance that works best for the song being played.
Utilize a coincident pair of microphones inside the piano for a modern sound with mono capability. Spaced pairs of microphones can sometimes have phase issues when played back in mono, but a coincident pair will convert down to mono nicely. Start out by placing the microphones 8 to 10 inches above the strings directly behind the music stand of the piano. Keep the microphones closer to the hammers for a brighter sound or move the microphones further toward the back of the piano for a warmer sound. Move the coincident pair of microphones closer to the strings for a more direct sound or farther away from the strings to capture more of the room. Increase the angle between the coincident pair of microphones for a wider image of the piano, or decrease the angle between the microphones for a more narrow image.
Utilize an ambient technique for a more classical sound. However, this technique should only be used if the piano is in a good sounding room. Place a single microphone or a stereo pair a couple feet away from the piano. If using two microphones, a coincident technique will prevent phase problems from negatively affecting your sound. The farther away from the piano the microphones are, the more of the sound of the room the microphones will pick up. Placing the microphones in line with the hammers of the piano will achieve the brightest sound, while placing the microphones behind the piano will result in the dullest sound. For capturing more high end from the piano, position the microphones at a height at which they can “see” the strings of the piano. Vary the positioning of these microphones until you’ve achieved the piano balance you are after. Combining an ambient microphone technique with a close microphone technique can sometimes create a sound that takes advantage of the best of both techniques.