It is to the advantage of every pianist and teacher to understand certain fundamentals of piano construction and maintenance, so that he can know what to expect from his piano and his piano technician. Piano owners sometimes expect the impossible from their instruments: I have heard unjustified complaints about tunings and minor repairs done by very fine technicians. On the other hand, I have seen pianos that have been so badly rebuilt (because of an unwise choice of technician) that there was no remedy except to rebuild them again, at great expense to the owner – and unfortunate situation in every respect. A teacher who knows the basic facts about piano maintenance will be able to select a good technician and put the piano into his case with confidence.
In order to discuss easily with the technician the needs of your piano, you should start by speaking the same language. Take, for example, the identification of particular keys. All piano tuners use a simple system of numbering the keys: the lowest A in the bass is number 1, and each key in the ascending chromatic scale is numbered in succession – the highest key in the treble is thus number 88. These numbers identify not only the keys themselves, but also the action parts moved by these keys, and the pitches the produce.
Keys can, of course, be identified as “sub-contra A,” “three-line C,” and so forth, but many tuners are unfamiliar with this nomenclature, and many musicians have forgotten its details. If, however, you leave a note for your tuner telling hum that there is a squeak in number 73, he will know immediately what you mean.
The first thing you will want to discuss with your technician is the most common service needed – tuning. Even though pianists have seen this operation many times, a review of tuning procedures is an useful prelude to a discussion of more complicated services.
Regular tuning is necessary not only to keep a piano up to pitch, but also to prevent damage to the instrument. All pianos today are designed to be tuned at A-440. This means that the A above middle C (number 49 in the piano tuners’ system of identification) will vibrate at 440 cycles per second. The A below middle C – number 37 – will thus vibrate at 220 cycles per second, and middle C itself – number 40 – at 261.6256 cycles. Piano strings are under heavy tension – about 160 pounds per string – and if a piano is left untuned for more than a year (of if the tuner fails to raise the general level of the pitch when tuning a neglected piano), the pitch will gradually drop as the strings loosen. This is true whether the piano is brand new or very old. It is common to find pianos a full semitone below pitch when they have not been tuned in some time; instead of A 440, these instruments have an “A” 415 – the A has settled all the way down to A flat (415.3047 cycles per second).
Suppose that yours piano has not been tuned in some time, or that you have just bought a fine piano from someone who has neglected it. When the tuner arrives you can expect him to tell you something about the general level of the pitch. If the piano is a semitone flat, he will probably recommend more than one tuning during a period of two weeks or a month. The tuner will first bring the piano up to pitch, greatly increasing the tension on the strings. I have heard complaints that a tuner bringing a piano up to pitch sailed through the job as if he were in a hurry to leave; but the best tuners will in fact work as rapidly as possible during this process. The strings pull with a for of some eighteen tons on the metal frame to which they are attached, and this force must be redistributed very quickly to avoid abnormal stresses on the frame and soundboard resulting from inequalities of tension.
When this job has been completed (it will probably not be necessary if your piano has been tuned regularly), the tuner will tune it again, doing a more precise job; this is commonly called the fine tuning. Here the mark of a good tuner is that he moves the tuning pins (and therefore the strings and the pitch) as little as possible. The less the pins need to be moved – in other words, the less the pitch itself is altered during the process of tuning – the better the piano will stay in tune. The expert tuner will therefore use a great many aural tests to determine before he moves the pin whether the pitch is flat or sharp, and the approximate amount of its deviation. Once he knows this, he can bring the string to the correct tension with a minimum of experiment. The tuner who cranks the pitch of a string violently up and down during the fine tuning process may get it in tune; but it will not stay on tune for long, because the tension of the string has been changed too much.
In areas where warm humid weather prevails throughout the year, the pitch of a piano will remain constant if it is tuned regularly – the A will stay very close to 440. Wherever the weather is cold in winter and hot in summer, however, even a piano that is tuned regularly can be expected to drift slightly from these frequencies during the course of the year, because of natural changes in humidity. (This small seasonal drift must not be confused with the radical drop in pitch of a long-neglected piano!) An A set 440 in the fall will drop gradually to about 436 in the winter, and then raise slowly through 440 again in the spring up to 442 (or even higher) in the summer. Many experienced tuners therefore suggest that pianos be tuned just after the heat goes off in the spring, and just after the heat is turned on in the fall. When a piano is tuned in summer or winter, the tuner will often take the season into account and adjust his standard pitch accordingly, leaving the piano a bit high in the summer and a bit low in the winter.
A tuner begins by testing the pitch against a tuning fork, which may sound either A-440 or C-523.3 (keys number 49 or 52). The note an octave below the fork is tested and tuned. A series of fourths and fifths is then tuned in a certain order of semitones tuned with great accuracy. Thirds and sixths are used both to test the precision of the tuning, and as part of the tuning itself. When the temperament has been set in this way, the rest of the strings tuned in octaves, up and down the keyboard. Thirds, sixths, tenths, fourths, and fifths are used to prove the octaves.
In fine tuning, there are two possible procedures both in the setting of the temperament and in tuning the bass and treble. The tuning of each unison may be completed before going on to the next (i.e. all three strings of a three-string unison – the three strings struck by a hammer – may be tuned). Or else the center strings of a group unisons may be tuned while a felt strip or many rubber wedges mute the outer strings, which are left to be tuned in a later operation. Both methods have their advocates, but the former method (the complete tuning of each unison) allows greater precision and permanence. A tuner employing this method will use two rubber wedges; he will not need a felt strip nor a large number of wedges.
Learning to Hear Beats
Let us assume that your piano has just been tuned. When your tuner leaves, you can begin a series of observations that will help you to learn what to listen for in a tuning. In each of these, you should hold the keys down and listen until the sound almost dies away.
1. Listen to each note in turn, from number 1 through number 88. Each should sound smooth and clear if the unisons have been tuned well.
2. Test all the octaves, from the bottom of the keyboard to the top. The octaves should be smooth and clear. But don’t be alarmed if there is some waviness or lack of clarity in certain notes. Many pianos have particular strings that are not perfectly clear, and piano teachers are often able to hear these imperfections of the strings.
3. Play fourths upward from E-A (32 and 37) to G-C (47 and 52). You will notice a slow crescendo and diminuendo in these intervals, slight waves in the sound that are called beats. The tempo of these beats should increase gradually and regularly as you go up the keyboard. (The metronome will give an approximation of the tempo, so that you will know what to listen for – the E-A interval will beat at about M.M.=44, and G-C at M.M.=106.)
4. Play fifths from E-B (32 and 39) upward for two octaves. The beats in the fifths should be even slower than those of the fourths, but they, too, should gradually become faster as you go up the keyboard. (The lowest fifth in this test, E-B, should beat about thirty-three times per minute. Set your metronome at 66, and listen for one pulsation with every second tick of the metronome.)
5. Play major thirds from E-G# (32 and 36), continuing upward as far as you can hear beats that are much faster and more noticeable than those of fourths or fifths. Again, the beats should become steadily more rapid as you ascend. (The first third, E-G#, will beat about 392 times per minute. Set the metronome at 196, and listen for two pulsations to each tick).
If you can’t hear any of the beats, don’t be discouraged. This is a particular kind of listening, and your ear will become accustomed to it if you keep trying. Repeat the entire series of five observations several times a week. After a few weeks, as your piano goes slightly out of tune, you will notice more and more irregularities. By the time your tuner comes again, you will be prepared to discuss the tuning with him, and the two of you will be talking about the same thing. It may be wise to point out a few bad unisons to him before he begins to work, to find out how he will respond. He may be willing to help you by checking your observations.
I know one piano teacher whose natural aural talent was such that after listening diligently in this way, she was able to tune her own piano (though this is not a practice that I can generally recommend). But I have never met anyone who was able to tune a piano or to carry on a successful business as a technician after doing nothing more than take a correspondence course in piano tuning and technology, even though the woods are full of such “tuners.” Inquire discreetly into your tuner’s training. If he has been trained in a piano factory, or if he is a graduate of a recognized piano technician’s school, he is likely to be an adequate craftsman. The same is true if he has served an apprenticeship under an expert technician for four or five years, or if he has been resident tune in a school of music for several years.
The question often arises as to the status of electronic tuning devices. Electronic aids, both audio and visual, are very accurate tools for measuring pitch. But the tuning of a piano depends on far more than simple tuning of the frequency of each pitch. Tuning depends on a subtle balancing of the fundamental and the overtones of each pitch: the warmth and musicality of piano tone depends on just this balance. The behavior of a vibrating piano string remains a mystery in many of its aspects, despite the considerable amount of scientific work on the subject. It is therefore left to the ear and judgement of the tuner who must approach tuning partly from an esthetic point of view, to attain the optimum tonal balance for each piano. A tuner using an electronic tool is certainly not entitled to any higher fee for tuning than whatever may be current in the area. The ultimate proof of tuning done entirely by ear: the accuracy and smooth progression of the beats, and the relative permanence of the tuning. Any tool is legitimate, but my own experience is that the work of tuners relying on electronic aids has not on the whole been good. I believe that this is because many of these men have never been trained in such fundamental techniques as testing tuning pins for solidity of position, and so forth.
If your piano has stayed in fairly good tune, the tuning itself will go quickly enough so that the tuner can be asked to clean the piano. He will clean the soundboard of a grand piano with a cloth pushed under the strings by a long flat piece of flexible steel. The area around the tuning pins on grands collects dust that you yourself can sweep away by brushing vigorously with a clean medium-size paint brush.
At least once every five years, the felt under the keys should be thoroughly cleaned. The keys on an upright piano can be removed one at a time without disturbing the rest of the action. On a grand piano it is necessary to remove the entire playing mechanism, which can be taken out as a unit and set on a table (where it will work almost as it does in the piano). The action is taken apart by the technician; keys are removed, and the felt is brushed and vacuumed. Cleaning the keyboard may help to prevent moths from attacking the felt; it unquestionably helps the keys to work more evenly, and it may thus be considered to be one small aspect of regulation.
The proper regulation of the piano action – that is to say, the perfect adjustment of all mechanical parts between the finger and the string – is essential to control of the key by the pianist. It affects not only the feel of the keyboard and the speed with which a note can be repeated, but the evenness of the dynamics and thus the tonal qualities of the instrument in actual performance. Regulation is as important as tuning.
The keys of a piano in good regulation should be perfectly level. This is most easily seen on the white keys: if some of the keys are slightly higher or lower than the adjacent keys, the action needs some adjustments. The tolerance is very close, and in no case – even allowing for normal variation in the wood of the keys, and in the thickness of their ivory or plastic tops – should there be a variation greater than the thickness of a business card. The black keys, too, should be level; they can be checked with a straightedge. (The piano is played much more in the middle register than in the bass or treble, and the felt washers – or punchings – on which the keys rest will pack down sooner in the middle of the keyboard. When pianos are new or just been regulated, the center of the keyboard may arch upward slightly to compensate for the expected compression of the felt.)
A well-regulated keyboard is slanted slightly away from the performer when the keys are at rest. When a key is depressed, it slants toward the performer. The end of each key should travel downward three-eighths of an inch. This key dip should be uniform throughout the keyboard. Any group of black or white keys depressed together should level in their depressed position. And no black key should go down far enough to allow the tip of the pianist’s finger to touch the white keys when the black key is depressed.
Hammer Behavior on Grand Pianos
Push any key down very slowly. When the key is nearly all the way down, there will be a slight resistance. This is called the after-touch. The position of the after-touch within the key descent should be uniform: it should not be high on the key, low on the next, and non-existent on another. The amount of resistance should also be about equal on every key, becoming a little lighter as you go up the keyboard.
If any of these conditions is not fulfilled, then your technician should be consulted. Every felt part of the action packs down with use, causing errors in the regulation. These can first be noticed as a general irregularity of key level and hammer behavior.
Slide the music rack forward or remove it so that you can see the hammers by looking down through the strings. Depress a key very slowly and gently so that it does not produce a tone. The hammer should never reach the string. When it is a short distance from the string – about the thickness of a quater – it should suddenly drop back slightly to a position approximately the thickness of two quarters from the string. When the key is released, the hammer will drop all the way back to its rest position. The hammers should rest suspended in the air no more than 1 7/8″ from the string. All hammers should be level in their rest position.
Now give the key a hard blow so that the hammer strikes the string forcefully. Hold the key down; the hammer should rebound from the string to a position about five-eighths of an inch away, where it should remain until the key is moved. (There should be no upward bounce of the hammer.) Release the key slowly. A very slightly upward motion of the key should cause the hammer to rise gently to a position near the string (about the thickness of two quarters). The upward motion of the hammer should be smooth and steady: it should neither jump, not lag, nor fail to move.
Hammer Behavior on Uprights
The hammers of an upright are easier to see than those of a grand piano; there is an unobstructed view from above whenever the lid is open. An upright action is, of course, differently designed from that of a grand, and there is an important difference in hammer behavior. When the key of an upright is given a sharp blow, the hammer will strike the string and fall back to a position about five-eighths of an inch from the string. When the key is depressed silently, the hammer will reach a point about an eighth of an inch from the string and fall directly back to a position five-eighths of an inch from the string, without stopping in an intermediate position.
The dampers of both grands and uprights will touch the strings when at rest. A damper should begin to move away from its string when the key is about halfway down. A damper should be lifted slightly farther by depression of the damper pedal – otherwise a jolt may be felt through the keys if the pedal is suddenly released while several keys are held down. Watch the dampers as you slowly depress the pedal; they should all rise in a fairly uniform manner.
The heaviness or lightness of an action is determined by the manufacturer. Many different factors of design are involved. It is not something that can be adjusted; but an action in good regulation is very responsive to the player’s touch and is usually felt to be “lighter” than an unregulated action. (Artificial methods may be used to change the weight of an action: lead weights, for example, can be attached to the underside of the keys to make an action heavier or lighter. An expert technician may recommend their use under certain circumstances. but they remain makeshift.)
Good piano tone depends on a well-regulated action with an even touch throughout, perfect tuning, and hammers that are properly shaped and voiced. Hammers become deeply grooved with use. As the grooves deepen, more of the hammer strikes the string and the tone quality is impaired. The hammers then need to be restored to their original shape by the use of sandpaper files and strips. All hammers are then voiced by softening or hardening the felt in order to produce a particular tone quality. The felt is pricked with needles to soften the tone. To make the tone more brilliant, the felt is hardened either by application of heat near the striking point, or through the use of lacquer-like solutions called hammer solidifiers. These solutions (not to be confused with common lacquer) harden the felt to the desired consistency without themselves becoming entirely hard. When applied judiciously in the hammer so that their effect can be modified and perfected by needling.
Voicing should leave the felt of all the hammers well set at a particular consistency. Slight variations in the tone quality of certain notes may occur within the first fifty to one hundred hours of playing, however, and these hammers should be called to attention of the technician when he comes to tune the piano. He can touch up the voicing. A conservative approach toward this touching-up is best. It is easier to reduce the brilliance of a hard hammer than it is to make a soft hammer brilliant. (It is not difficult to reduce brilliance by needling, but the only practical way to increase the brilliance of hammers is to file away the felt with sandpaper.) It should be borne in mind during all such operations that if too many hammers have been separately voiced, the unity of the piano’s tone quality may be lost.
Tuning and voicing are two facets of the same general project: making a piano sound its best. In factory operations, two men work together on the final adjustment – a tuner and a voicer. The piano is first given a fine tuning. This makes is possible for the voicer to hear discrepancies in the tone quality of the hammers; he makes the necessary alterations in the texture of the hammers; and the tuner then tunes the piano again. The two processes are interdependent. Voicing cannot be done successfully unless the piano is in perfect tune, but even the most perfect tuning will not make a piano sound its best without a fine job of voicing. Outside the factory, these two operations are performed by a single tuner-technician, who must be a master of both.
Voicing is the most important and most demanding part of all piano servicing. Be sure that you are well acquainted with the quality of a technician’s work before you let him voice your instrument. No voicing should ever be done unless you have discussed with the technician the tone quality that you want your piano to have; different tone qualities are possible, and your technician can help you to understand the various effects that voicing can have on tone.
Determination of the point at which the hammer should strike the strings is of great importance but is a highly technical matter. Few tuners are capable of setting or correcting the striking point – most are dependent on the original setting of the manufacturer. (The Piano Technicians Guild holds seminars and work clinics to educate tuners and technicians in such abstruse matters.)
On any piano that has been tuned, regulated, and voiced by an expert, there may remain questionable tone colors in certain areas of the keyboard. (The piano string is still to some extent a mysterious thing.) For example, there is a point where the beat frequency of a major thirds begins to become an indistinguishable flutter because of its great speed. The thirds situated at this point – Eb-G and E-G# (43-47 and 44-48) may sound inharmonious and unpleasant. There are musicians who find this very annoying, but in certain individual pianos there is nothing to be done about it. Another common and upsetting malady, to which the better pianos are unfortunately prone, is the buzzing and ringing of certain strings. This is caused by the enormous tension of the string at its bearing points, such as the bridge. Your tuner may be able to find a remedy, but some cases are incurable.
No one has a keener sense of the impermanence of all things than the piano technician. What is a piano? A piano is a construction of wood, metal, leather, and felt; These materials react differently to changes of temperature and humidity. For this reason, a piano is no sooner tuned or regulated than it begins to go out of tune and out of regulation. The greater part of work for concert artists consists of small adjustments in tuning and regulation: a piano must have daily attention if it is to be kept in perfect tune and optimum working order. For this reason concert pianists sometimes hire tuners on a full-time basis.
Though full-time service of this sort is hardly practical for most teachers, every piano should be tuned at least two to four times a year. The action should be regulated every three to five years – more frequently if the piano is heavily used, or if especially fine results are needed.
A good piano bought new in 1966 and used by a teacher for six hours a day ought to have its hammers filed and voiced about every two years. The hammer heads should be replaced in six years. In twelve to fifteen years, the hammer shanks should be replaced along with the head.