Keyboard Magazine "In The Studio"
Article # 8
ACOUSTIC PIANO MIKING TECHNIQUES
By Bobby Nathan
First off before we begin, I'd like to say that every engineer I've ever met, has his own way to record acoustic piano. Now don't be alarmed by this! It's just the way it is. If anything, knowing this should lead you to experiment with your particular room and instrument. The reason all engineers have different methods is because they record in their favorite studios which already have a piano there. Being that the piano is an acoustic instrument, factors such as the size and treatment of the room versus the type of acoustic piano sound you're going for ( classical, jazz, rock or R & B ) all have to be accounted for. There are so many variables in recording acoustic piano that in many ways it can be compared to a synthesizer. Some of the methods I'll be discussing are not the only ones, but because of space reasons will have to do for now!
The most important factor to consider is what style of piano first. This will help in deciding where to record piano. For instance if you want to record a rock piano sound from an instrument that has not been set up for that style of music, its just not going to come off as well. Piano prepared for rock music has had its hammers treated with a substance to harden them. Don't try it on your own instrument! If you want a brighter, thinner sound from your piano hire a technician. On the other hand certain pianos have had their hammers pricked with a needle to soften them. This brings a warmer sound to an instrument that was bright to begin with. For classical and jazz music this is more desired. Once again you should hire a professional to set up your piano. As you can see, having the piano set up for the style of music you'll be recording is essential.
Now, in getting to microphones. I would suggest condenser type microphones ( AKG 414, 451, Neumann U-87, U-47fet, Shure SM-81 ) for a brighter, more crystaline type of high end response more suitable for rock and R & B but can used for other styles with proper placement. The vintage tube type of condenser microphones ( Neumann M-49, U-67, U-47, AKG C-12, Telefuken 251 ) found in most studios are well into the $1800 range and above. They posses a more natural sounding high end and fuller low end response than the transistor preamplifier stage of many of the newer microphones. In many ways the tube microphones should be compared to tube guitar amps. Because of the tube the third harmonic and all the odd harmonics are reproduced from the piano's sound. Dynamic microphones ( Shure SM-57, SM-58, Sennheiser 421, 441, Electro-voice RE-20 ) are widely used as well. They also give excellent results. Being that they are transformer based they can as a rule accept higher sound pressure levels than the tube condensers microphones. Because leakage is always a problem when miking acoustic piano with other instruments on stage or in the room, Pressure Zone Microphones ( Crown PZM ) have found their nitch in acoustic piano miking. They can be mounted on the inside of the lid on the piano and with the lid closed can produce a workable sound with very little leakage. The next important factor is what type of pattern to use when miking the piano. Many of the microphones I mentioned above have multiple polar patterns. In choosing one you must consider again the type of style of piano, leakage factors and phase cancellation. Phase cancellation occurs when two microphones are placed in close proximity. What happens is certain frequencies cancel out making for a lack of those frequencies. When you have two microphones close together under a piano lid and set to undesirable polar patterns the result will be a very unnatural sound. For rock music the microphones have to be as close to where the hammers hit the strings as possible. Cardiod and Hyper- Cardiod microphones work best. They are more directional. They pickup less from behind and thus cut down on leakage. They are also less prone to phase cancellation. AKG 451, 452, 414's and Neumann U-87, U-67, U-47 fet and tube, KM-84 are good examples. The PZM's are also excellent alone and in conjunction with the cardiods mentioned above. For classical piano and jazz piano the omni-directional patterns work best. It is usually desirable to record the room sound along with the sound of the piano. For classical music it is customary to place the microphones outside the piano on the side of the lid that opens. This allows the piano to breathe. Since it has always been argued as to where there piano's sound emminates from, miking the piano from where in the room it sounds most natural is what is important.
Alright but where do we put the mikes? Well as I started to say for rock piano two mikes can be placed close to where the hammers hit the strings.They are usually panned anywhere from hard left and right to nine and three o'clock for stereo, but always should be checked in mono for phase cancellation. They can be at either end of the piano over the hammers facing in or as I prefer in the middle over the piano slightly facing out. The later way has less phase cancellation. Now if you're going for a very bright percussive sound you can make good use of a little phase cancellation to thin the sound out.I suggest the AKG 451's with the A51 swivel mounts. The A51's allow the capsule of the 451 to be at a 90 degree angle to the body of the mike. You can use these when the lid down low so that the 451's with omni-capsules placed right over the hammers. For added low end a third microphone placed in the rear of the piano can be added and panned up the middle. A pair of PZM's on the lid in conjunction also works great. Unfortunately if you're trying to record rock piano in a room or on stage with loud amps a blazing you're not going to be able to use those omni-directional patterns for a little phase cancellation. In fact you're going to have place gobo's ( go betweens ) around the piano and cover it with blankets. On stage this is unsightly so you might might to use the PZM's. Elton John had a custom shell constructed around his piano for live concerts to minimalize feedback. You might want to construct a similar shell, but keep in mind the lights are optional!
In miking jazz piano one must keep in mind that whether on stage or studio it's always live! Microphone placement is important because jazz musicians are not interested in headphones, they want to perform as natural as possible. Try working with less microphones carefully placed around the stage or studio. This will eliminate more phase cancellation and produce a more natural sound. Of course it should not be taken to the extreme of not hearing the piano player. In jazz a more mellow piano sound is required so try and mike the piano from the rear as well as the right side, keeping away from the hammers hitting the strings and focusing more on the soundboard. If you don't have expensive tube microphones to work with, try the dynamics. In general stereo pairs are best of the same microphone but combinations do work too! Don't be afraid of trying things. Shure SM-57's and Sennheiser 421's and Electrovoice RE-20's all work well together. You can even use one condenser with a dynamic. It all works.
One of the things that we didn't discuss is using Eq. and compression. Before you add any equalization from the board, you should work with mike placement. You may just get the sound you're looking for without adding tons of Eq.. It's not that Eq. is bad, it's just adds noise. In jazz or classical music noise is not acceptable. During quiet passages on ballads too, noise is the enemy. Compression can be used to reduce the dynamic range of the piano. Since the dynamics are so wide a little compression and or limiting can make a piano much more enjoyable to listen to. This holds true for rock, jazz, classical and especially on ballads. But be careful as too much compression can add noise and if the way you had Eq'd the piano added noise, too much compression can bring the noise level to a most noticeable hiss. Another effect is to add a little chorusing or harmonizer at 99 or 101 for a Honkey-Tonk type sound without detuning the instrument.
Oh, and if I didn't mention it be sure the piano is in tune before you start working on the sound. You don't want to be moving microphones after you've gotten the sound up because the piano is out of tune.
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