Some of the most popular instruments in many genres of music are keyboards, so let’s look at some techniques to capture a grand piano, upright piano, Leslie organ speaker, digital keyboard or synthesizer.
This magnificent instrument is a challenge to record well. First have the piano tuned, and oil the pedals to reduce squeaks. You can prevent thumps by stuffing some foam or cloth under the pedal mechanism.
One popular method uses two spaced mics inside the piano. Use omni or cardioid condenser mics, ideally in shock mounts. Put the lid on the long stick. If you can, remove the lid to reduce boominess. Center one mic over the treble strings and one over the bass strings.
Typically, both microphones are 8 to 12 inches over the strings and 8 inches horizontally from the hammers (Figure 1). Aim the mics straight down. Pan the mics partly left and right for stereo.
The spaced mics might have phase cancellations when mixed to mono, so you might want to try coincident miking (Figure 1-A). Boom-mount a stereo mic, or an XY pair of cardioids crossed at 120 degrees. Miking close to the hammers sounds percussive; toward the tail has more tone.
One alternative is to put the treble mic near the hammers, and put the bass mic about 2 feet toward the tail (Figure 1-B).
Another method uses two ear-spaced omni condensers or an ORTF pair about 12 to 18 inches above the strings. With the ORTF stereo mic method, two cardioid mics are angled 110 degrees apart and spaced 7 inches horizontally.
Boundary mics work well, too. If you want to pick up the piano in mono, tape a boundary mic to the underside of the raised lid, in the center of the strings, near the hammers.
Use two for stereo over the bass and treble strings. Put the bass mic near the tail of the piano to equalize the mic distances to the hammers (Figure 1-C). If leakage is a problem, close the lid and cut EQ a little around 250 Hz to reduce boominess.
If your studio lacks a piano, consider using a software emulation of a piano. Some programs provide high-quality samples of piano notes that can be played with a sequencer or a MIDI controller.
Moving on, here are some ways to mike an upright piano (Figure 2):
A) Remove the panel in front of the piano to expose the strings over the keyboard. Place one mic near the bass strings and one near the treble strings about 8 inches away.
Record in stereo and pan the signals left and right for the desired piano width. If you can spare only one mic for the piano, just cover the treble strings.
B)Remove the top lid and upper panel. Put a stereo pair of mics about 1 foot in front and 1 foot over the top. If the piano is against a wall, angle the piano about 17 degrees from the wall to reduce tubby resonances.
C) Aim the soundboard into the room. Mike the bass and treble sides of the soundboard a few inches away. In this spot, the mics pick up less pedal thumps and other noises. Try cardioid dynamic mics with a presence peak.
Leslie Organ Speaker
This glorious device has a rotating dual-horn on top for highs and a woofer on the bottom for lows. Only one horn of the two makes sound; the other is for weight balance.
The swirling, grungy sound comes from the phasiness and Doppler effect of the rotating horn, and from the distorted tube electronics that drive the speaker. Here are a few ways to record it (Figure 3):
• In mono: Mike the top and bottom separately, 3 inches to 1 foot away. Aim the mics into the louvers. In the top mic’s signal, roll off the lows below 150 Hz.
• In stereo: Record the top horn with a stereo mic or a pair of mics out front. Put a mic with a good low end on the bottom speaker, and pan it to center.
When you record the Leslie, watch out for wind noise from the rotating horn and buzz from the motor. Mike farther away if you monitor these noises.
Rather than recording an actual Hammond B3 organ and Leslie speaker, you might prefer to use a software emulation of those instruments: an organ soft synth or sample and a Leslie rotating speaker plug-in.
Trigger the synth or sample by a MIDI sequencer or MIDI controller. You can automate the horn rotation speed in the Leslie speaker plug-in.
Synthesizer, Digital Keyboard, MIDI Sound Module, Drum Machine & Electric Piano
So far we covered acoustic keyboards which you pick up with a microphone. Now let’s look at electronic keyboards which you record with a cable.
One system uses a MIDI controller keyboard to trigger a software synthesizer (soft synth) in a computer recording program (Figure 4).
This is a whole subject in itself. Basically, the MIDI controller produces MIDI messages when you play it. These messages tell which keys you pressed, how hard you pressed them and when. It’s not an audio signal.
Figure 4. Recording and playing a soft synth using a MIDI controller keyboard.
A MIDI controller can be any electronic keyboard or drum machine that has a MIDI OUT connector. The MIDI signal triggers a soft synth in your computer. That synth can play any sound, such as a piano, bass, string section, and so on.
You record using a computer with an audio/MIDI sequencer program. After recording the MIDI events (the sequence), you can edit the MIDI notes to correct errors: change their pitch, timing, or duration.
Another way to record an electronic keyboard is to record its audio signal. For the most clarity, record the signal directly from the instrument.
In Figure 5, the top two parts show two ways to do it. Either plug the instrument into direct boxes, or into two phone-jack instrument inputs on your mixer or audio interface.
Figure 5. Three way to record the audio signal of an electronic keyboard.
Set the volume on the instrument about three-quarters up to get a strong signal. Try to get the sound you want from patch settings rather than EQ.
If you connect to a phone jack and hear hum, you probably have a ground loop. Here are some fixes:
• Power your mixer and the instrument from the same outlet strip. If necessary, use a thick extension cord between the outlet strip and the instrument.
• Use a direct box instead of a guitar cord, and set the ground-lift switch to the position where you monitor the least hum.
• To reduce hum from a low-cost synth, use battery power instead of an AC adapter.
A synth can sound dry and sterile. To get a livelier, funkier sound, you might run the synth signal into a guitar amp, instrument amp, or power amp and speaker. Mike the speaker cone a few inches to a few feet away (Figure 5, bottom part).
You might mix the microphone’s signal with the direct signal. If your recording system has a polarity button in the mic’s channel, flip the button in and out, and choose the position where you monitor the best sound.
Does the keyboard player have several keyboards plugged into a keyboard mixer? You may want to record a premixed signal from that mixer’s output. Record both outputs of stereo keyboards.
A member of AES and SynAudCon, Bruce Bartlett is a live sound and recording engineer, microphone designer (http://www.bartlettaudio.com), and audio journalist. His latest book is Practical Recording Techniques, 6th Edition.