The acoustic piano has long been a staple instrument in reinforced pop music including rock, folk and jazz. And none would argue that it has always been a very important part of worship music, in both traditional gospel and modern styles. But like so many of the obstacles that we who do live sound are faced with, micing an acoustic piano and meeting all of the needs is seldom an easy proposition.

Why So Complex ?
The grand piano is, well…….a grand-sized instrument with typically 88 keys that actuate the hammers that strike over 250 strings, producing fundamental frequencies from 27.5 Hz to 4.2 kHz and overtones that extend this frequency range to well over 20 kHz, all combining to make this an impressively rich sound source. The body of a piano is of considerable volume and the lid can be used at four positions: open/full stick, open/short stick, closed and (in very few cases) - removed. The later two lid positions are those that have been found to be useful in some cases for reinforced music and are not used for traditional unamplified events.

The piano is a wonderful combination of percussive and tonal sounds. Each time a key is depressed a hammer strikes the string(s) and, depending on the position of the damper pedals, the note is either immediately dampened or it is allowed to sustain until either the pedal is released or the note(s) naturally decays. For both gospel and modern worship music a precise and percussive playing technique is often preferred in order for the piano to stand out in and drive the music.

Recording solo acoustic piano in a classical music or “new age” setting, and especially in an acoustic space suited to this style of performance, there is great benefit from “distant” micing of the instrument. Part of this is due to the very shape of the piano body and lid, which are designed to project and reflect the sound outwards. You would do very well with single or dual high-quality omnidirectional microphones placed above or above and forward of the instrument and with the lid on full stick. Since this is a recording-only application and there is no reinforcement system involved, no competition with other instruments, there is much to be gained by fully capturing the natural sound of the instrument. When recording or reinforcing a small jazz, folk or ethnic music combo consisting of seasoned (disciplined) performers — who have no need for stage monitors and who played at barely-reinforced sound levels — you will likely use a pair of high-quality cardioid condenser microphones positioned two to four feet above the body of the instrument and with lid on full or short stick. In both of these cases you are not struggling to keep the piano distinctly audible in a complex mix of other instruments sharing the same frequency range and you have an opportunity (and the obligation) to pick up all of the nuances of this instrument and produce very natural sound.

But reinforcing acoustic piano in most other events including modern worship music is an ongoing struggle that can take extreme measures and requires much cooperation between the sound operators, music director or minister and the musicians. Care must be taken that you do not cause new problems in the process of providing solutions to others. Compromise is the name of the game and recognizing what is achievable (or more importantly: what is not) is a large part of doing this successfully.

Reinforcing the acoustic piano is similar in some ways to recording, and shares some same goals. Basically, you need to blend this instrument with the other musical instruments while maintaining sonic separation of each instrument. Guitars, organ, electronic keyboards, drums, vocals and horns are the primary competitors for the frequency range and dynamics that are produced by the piano. For piano, two microphones are required to capture the full range of the tones produced, and these are typically split between high and low hammers. Although there may be some leeway in recording that will allow the mic’s to be positioned at some distance from the hammers, in the dense mixes that construe a pop music recording or live performance it is most often beneficial to maximize the attack and definition of the notes being played and to minimize the pick up of ambient sounds, even when the piano is not threatened by leakage from adjacent instruments.

A note about “arrival times” is in order here. In terms of separation of one instrument from another, it is not a simple case of instruments with shared frequency ranges, etc. The larger issue is the delay that exists between varied sources. A microphone that is positioned over a piano also “hears” the sound from the nearby drum kit, from the bass player’s amp, from the saxophone situated six feet away and all of the signals fed into the stage monitors on the platform or stage. When mixed with the microphones and pickups that are positioned on those other instruments, the leakage of these instruments into the piano mic is offset in its arrival time and will result in a less precise, somewhat blurred combined signal. The same is true when using more than one piano mic. The treble mic will pick up those strings closer to the bass mic but at a reduced level. When combined, there will be some smearing here, as well, but this is a necessary artifact that does not outweigh the need for the two microphones. To minimize this time-based corruption of an otherwise clean signal, there are two techniques that will be most effective: employment of cardioid condenser microphones and positioning the microphones close to the hammers and strings. Realize that this is essentially a case of maximizing signal-to-noise. The source that you are trying to reinforce is the signal and leakage from other sources is noise. The more directional the mic is, the more it does not pick up sound coming in from the side and rear. The closer you place the mic to its source, the higher that source is in level compared to the leaked sounds that enter the same mic.

One can easily look around at shows or services, photo’s and a variety of publications to find how others mic their grand pianos. But it is really not that complicated to determine, on your own, the best mic locations for your own piano as they relate to the specific microphones and sound system being used. Simply lean in over the strings and hammers while someone is playing the piano (in a representative fashion) and listen for the best sounding positions. This is where you should initially place the microphones. Now go to the mixing console and solo each piano microphone as the player continues. Continue to aim and adjust the position of the mics until you have the most natural and clear sound possible. This is obviously best done by communicating to an assistant via intercom or talkback mic, who will move the mics at your direction. Now have the rhythm section play along with the piano and listen (through headphones and with the piano channels solo’d) to ensure that the piano is picked up clearly over the leaked sounds. Stage monitors should be activated at this time so that any contributions that they make to leakage can be observed. If necessary, make further aiming adjustments so that you maximize the piano sound and minimize extraneous sounds. Don’t lose sight of the fact that you’re focusing on clarity as much as any other sonic or musical quality. At this point you should begin to listen to the piano through the FOH loudspeaker system, played solo and then with the band. Provided you have a reasonably well-designed and optimized system, you should need only to make minor adjustments.

By and far, condenser microphones offer superior pickup of the grand piano as well as for most other instruments. Primarily it is the dynamic range and transient response of good quality condensers that separate them from dynamic microphones and results in superior attack and definition. Every year it seems there are more and more good condenser microphones that are developed and brought to market, and often at reduced prices.

Another potential benefit of the two-mic approach is that sound mixers can choose between a mono mix of the combined piano mics that may be panned to one side of the stereo mix and possibly opposite of the organ orother keyboards. Or, one can choose to pan one piano mic to one side and the other to the other side. This is sometimes helpful to separate the piano from within a dense mix or difficult room acoustic. It can also be equally effective for stereo in-ear monitor (IEM) mixes.

At some point during the piano sound check exercise, depending on a variety of factors, you may experience feedback from your piano microphones. Feedback will occur as a result of poor linearity of the loudspeaker systems, the relative positions of these loudspeakers to the piano mics and the sound levels that you are required to provide. Should feedback occur the surest way to stop it is to reduce the volume level of the piano and the entire mix. Make sure that the amplified instruments on platform and also the drums are not driving up the volume levels that the FOH and stage monitor systems are being run at. Once you have considered this, it is worth your time to revisit the positions of the microphones (Can they be closer ?) and look carefully at the positions of stage monitors (in particular the pianist’s stage monitor) to the piano mic’s.

It is not uncommon in sound reinforcement of acoustic piano to be in a position where you are unable to reduce feedback to an acceptable level. More often than not this will be the case with stage monitors which, due to their very proximity to the piano, are seldom able to function at the required levels without feeding back Fortunately there are some interesting devices to reduce or eliminate this problem.

Pickups are transducers that are affixed to the source instrument and transfer the mechanical vibrations into an electrical signal. To varying degrees they are not microphonic, ie: they do not pick up sound through the air. This is very important as it results in reduced leakage from other sound sources and has a tremendous impact on susceptibility to feedback. Up until recently there were only two piano pickup systems that were commonly available and both have their own specific characteristics and limitations. The C-ducer is a piezo-electric transducer housed in a flexible plastic strap-like body that can be easily taped to the inside surfaces of the instrument. It feeds into a preamp that outputs a balanced signal that is fed into the mixing console. Although quite popular with sound companies and some players for its ease of set up and reasonable cost, it provides fairly poor and uneven frequency response, is somewhat microphonic at higher levels and is not that durable when used on the road. But in my experience it simply does not sound very good. The Helpinstill pickup system was by far the better device available during the 1970’s an 80’s but it then disappeared from the market until very recently, when Ezra Helpinstill retained ownership and has released a new improved version that, at $550, has not changed in price since 1980. Although I have not yet had an opportunity to use it, based on my experiences with the original system it is likely to be quite good. It consists of three transducers that are mounted to the metal frame above the strings and close to the hammers. The three sections provide bass, middle and treble signals that are mixed into a single output for the sound system. It offers very full-bodied and distinct sound and requires a bit of blending to reproduce the piano’s frequency range evenly.

Within the past few years there have been several new pickup devices that have come to market and these also have promise. The Barcus Berry Model 4000 “planar wave” pickup is a piezo electric transducer (it looks like a small transformer) that is affixed to the soundboard below the metal frame and provides a very clean signal that is ideal for pop, worship and gospel music. Due to its very bright, metallic sound it requires judicious amounts of equalization to sound more natural. But it is basically non-microphonic and is therefore impervious to feedback. I have used these in many installations and live shows but I restrict its use to monitors while using high-quality microphones for the FOH system. At approximately $250, it is not a huge investment and it is inherently much more durable and easy to set up than the C-ducer and Helpinstill systems.

There are some new entries into the piano-specific pickup market from companies that manufacture pickups specifically for traditional acoustic instruments. These are reported to provide very high-quality natural sound, but have prices that put them a bit out of the reach of many churches. In a future article we will provide an extensive comparison of these systems to one another and to the other pick up systems.

Tom Young has been active in live sound reinforcement since 1973. He is now Principal at his own consulting firm, Electroacoustic Design Services in Ell Cerrito, California and serves as a member of “Church Production Magazine’s” Technical Advisory Board. He can be reached at tomyoung6@home.com.