This post is a continuation of my instrument series and describes the standard variations of recording piano, both grand and upright styles.
Ahhh piano. One of the quintessential instruments that almost everyone knows the sound of. Like the snare drum that I featured in my last how-to, the piano is a complex instrument with many timbres and qualities. The piano also has many sound sources that should be considered and respected when chosing the miking arrangement.
Piano is considered a percussion instrument because its sound is produced by hammers that strike the strings, creating a pronounced attack and even sustain. Most people chose condenser microphones for pianos to capture that attack, although ribbon microphones can be used for a mellower sound. Most dynamic microphones sound too harsh or undetailed for an adequate piano sound. Piano is also generally recorded in stereo with two microphones or a single stereo mic, although mono is acceptable if the sound will be integrated with other instruments or a ‘spot’ mic is needed to improve clarity in an overall blended image.
Grand Piano Sound Sources
The main areas where sound resonates in a grand piano are off the strings (rrrreally?), off the lid (the folding top thingy, especially when it’s up), the hammers, the body, and from underneath. The strings will have more attack the closer you get to the hammers and less the further away you get. The bottom will have a more midrangey sound. The lid will add a fullness and ambience. The further away from the piano you get, the more room you will capture. Generally, the further from the piano you get, the higher the mic should be positioned to allow the sound to ‘bloom’.
The two most common ways to record a piano are to use a matched pair of cardiods. The first involves placing one mic on the low end of the piano and the other on the high end, both facing downward. The greater the distance, the more separation will result in the stereo image (and the great the chance of losing the midrange). As a result of the gap in between the mics, the further apart the mics are the higher they should be raised. Rotating the mics outward a bit increases the separation but increases the risk of phase issues in mono. Four inches to one foot is common, depending on how aggressively percussive the sound should be. The second is further out, just outside the body between the lid and the body for a fuller sound. A more ‘classical’ sound can be accomplished by moving the mic(s) even further back and up, even several feet away. Moving the mics into the body, toward the middle of the strings will decrease the attack and increase the resonance (it will get boxy quickly as a result of the body’s internal reflections).
Upright pianos resonate from the top, from the body, and from the strings (which are at the base of the piano, usually covered by a removeable ‘kickboard’). Removing the kickboard will usually open up the sound substantially.
Generally you’ll want to place a stereo pair just above the top of the piano for a roomier sound, or inside the piano, above the strings (facing the performer). The hammer point at the base of the strings can, after removing the kicboard, also be miked from the front facing the back (don’t kick the mics!).
In the Mix
Pianos often can use a bit of low-end management and clarity boost in the upper highs. The mids sometimes need some attenuation, depending on how busy your recording is. I tend to leave pianos uncompressed to allow them to breathe, but it’s not uncommon to compress them for a more even response or for more of an Elton John rock sound.
Pianos are really gorgeous instruments and, I think, are one of the most gratifying instruments to capture. Because people expect pianos to sound a ‘certain way’, it can both limit you to meeting those expectations and enable you to break them by doing something unusual. Have fun!