Regulation & Voicing:
What Buyers of Performance-Quality Pianos Should Know
Editor's Note: We prefer to keep articles in Piano Buyer as nontechnical as possible, in order to make them accessible to the largest number of readers. However, to satisfy the needs of more advanced pianists, we occasionally publish pieces that are slightly more technical, such as this one.
Regulation and voicing — the work of preparing a piano so that its touch and tone are even and beautiful — require a combination of painstaking technical adjustments and artistic considerations. Without this preparation, even the finest instrument is reduced to little more than a collection of parts, almost certain to disappoint. As a purchaser of a performance-quality piano, you have a much better chance of finding a suitable instrument if you have a basic understanding of these subjects.
Many pianists believe a piano's action or tone can't be changed, or that the performance quality of a piano or action is determined solely by its brand. But any piano's action can go out of regulation, become dirty and worn, suffer from neglect, or merely vary within a normal range — top-rated brands are no exceptions. Many wonderful instruments, new and used, are rejected by buyers because a lack of recent or competent service — or both — is disguising their true potential. Many a hidden gem is available to the buyer who asks the right questions, and can find the right technician to solve an instrument's problems.
Steinway & Sons pianos made in Hamburg, Germany, are considered among the finest instruments in the world. In the past several months, however, I have worked on three Hamburg Steinways, each of which had different problems that made it unsatisfactory to its owner. The solutions to their problems reveal much about action regulation and voicing in performance-quality instruments in general — but before introducing the pianos, I'll discuss the analysis and procedures used to solve these kinds of problems.
Analysis and Procedures
The technician must first assess what the piano needs, and then, taking into account the customer's goals and budget, make recommendations. The solution can range from a touchup regulation to a complete replacement of the action. If the owner's budget is slim, I try to first perform the least expensive and most effective steps, to mitigate the most serious problems. Usually I will regulate a sample key or section to show the customer what the results are likely to be, installing samples of new action parts where appropriate.
In explaining to clients how I address problems in piano regulation and voicing, I divide the subject into several sections:
Unless friction problems are solved prior to regulation, little real progress will be made. A piano's action contains thousands of friction points, mostly in places where pieces of cloth, felt, or leather serve as buffers between metal pins and wood. Too much friction can slow the working of the action and create what feels like extra weight in the key. The main culprits are dirty friction points, which make the action sluggish; the solution is to clean or replace the dirty parts and lubricate friction points. Knowing what to lubricate and which lubricants to use takes experience. Lubricants such as WD-40, oil, and wax can ruin a piano action, so don't try to do this yourself.
As part of the friction-control process, action centers — the points around which action parts pivot — must be repinned where necessary to correct inconsistencies in action-center friction. In very old pianos, especially New York Steinways of certain eras, buildups of verdigris — a greenish corrosion of the metal center pins in the action centers — can greatly stiffen the action parts, making them unplayable. In most such cases, these parts will need to be replaced.
A piano's action is an assemblage of levers that move in intersecting arcs of motion, and these parts must be installed in correct relationship to each other in order to operate optimally. These relationships are known as the action's geometry. Even in fine pianos, many reasons for geometry problems can arise. Some new pianos leave the factory with these problems, but most often they result from rebuilds done over the last 40 years, a period during which replacement parts in the original dimensions were often unavailable. In some cases, a piano born with poor action geometry has been rebuilt, and the problems have become even worse.
In the last 15 years, better parts have become available, and action manufacturers are now much more astute in anticipating the problems that can arise in replacing action parts. Piano technicians, too, have developed more sophisticated methods of addressing geometry issues, including: changing the locations of specific action parts, resetting the position of the entire action stack relative to the keyboard and strings, adding or removing action cloth, rehanging hammers, or installing a completely new action. Most important is that the proper analysis be made of the extent to which poor action geometry is contributing to the problems reported by the player.
As keys are played, pads of cloth, leather, and other materials serve to silence the action parts as they move. As these materials pack down and wear with use, the positions of the parts change slightly over time, and periodically need to be brought back to their original positions in order for the instrument to play properly, a procedure known as action regulation.
How often this needs to be done depends on how much the piano is used and the level of performance expected from it. Changes in action regulation occur so slowly that pianists generally remain unaware of them until they suddenly realize that their playing has become difficult to control. It may be years before the average amateur musician playing a piano in the home realizes this, but working concert instruments are regulated (and voiced) almost as often as they are tuned, and a fine piano in the home is no different if a professional level of performance is expected from it. The regulation will remain much more stable if very fine adjustments are made frequently, rather than infrequent wholesale changes made only in response to emergencies.
Piano actions have many points of adjustment that control the positions of the parts. The regulation procedure involves adjusting these so that each key feels the same when depressed. That may sound simple, but with keys being of different lengths, the hammers graded in size from bass to treble, hammer and action wear varying from section to section, and other variables, action regulation can be a daunting task involving thousands of steps. Most manufacturers provide regulation specifications for the actions of their current models; but for older instruments, when parts have been replaced, or when the pianist requests a particular touch, these specifications may no longer work and must be modified, which only increases the difficulty of the job.
Sometimes pianists' complaints about the tone, such as a lack of dynamic range or power, or the inability to play softly, are best remedied with fine action regulation instead of voicing. In particular, power in the action is the result of accurate and close regulation, not simply the hardening of the hammers (a voicing technique).
The touchweight, or downweight, is the amount of force needed to depress a key to the point of escapement with the damper pedal depressed. Most manufacturers today aim for a consistent touchweight across the keyboard of 47 to 52 grams, with slightly more weight acceptable in the bass than in the treble, due to the heavier bass hammers.
In weighing off a keyboard, gram weights are experimentally placed on each key to measure its downweight; other, permanent weights, of lead, are inserted in or removed from holes drilled in the side of the key, to bring it to its proper downweight. A keyboard can be weighed off only after the action's friction and geometry have been checked and corrected, and the action regulated. Frequently, after the fine regulating is finished, only minor weight changes are necessary to even out the touchweight.
Many touchweight problems are the result of installing replacement hammers that are heavier than the originals. Heavier hammers can be used, but the added weight must be offset by changes in action geometry, which will often necessitate replacing other action parts as well. Simply adding lead weights to the keys to counterbalance heavier hammers, even when this results in nominally correct touchweight, may make the action sluggish during rapid playing due to increased inertia in the action system.
Voicing, or Tone Regulation
When the action regulation and weighoff have been completed, the tone regulation can proceed. However, if the strings have worn deep grooves in the hammers, the hammers must be filed before action regulation and weighoff, because removal of so much felt reduces a hammer's size and weight. Deep string grooves cause the tone to suffer, both from slight damping of the strings and because the hard, crusted felt creates noise on the attack.
After filing, the hammers must be fitted to the strings, a painstaking process that must be done before any needling of the hammer felt. Due to slight inconsistencies in the heights of the strings, the hammer angles, and/or any previous filing, tiny amounts of felt must be filed off the top surfaces of the hammers so that each hammer strikes both or all three of the strings assigned to it at precisely the same time. This ensures that all that hammer's strings are put in motion simultaneously, which will greatly improve the tone. Some technicians might initially address this problem on a new or newly rebuilt piano by leveling the strings, but eventually this fitting must also be done by minutely filing or ironing the felt.
Once the hammers are filed and fitted to the strings, the actual work of setting the tonal level and evenness can begin. This is the part of the job most likely to require and benefit from customer input, to ensure that the customer's tonal preferences are satisfied. If radical changes to tone are desired, I prefer to do several voicing sessions, gradually changing the sound each time. Between visits, it's important that the pianist have an opportunity to listen carefully to what I've done, and to play-in the hammers to settle the felt.
Harder hammers produce a brighter sound, softer hammers a mellower sound, but many other shades of tone are possible between bright and mellow. Needling the hammers evens out the consistency of the hammer felt so that each hammer has the same amount of compression and tension and, therefore, should sound the same. Needling different areas of a single hammer will give different results; here, an experienced voicer can make all the difference.
Adding a hardening lacquer to the hammers can add body and depth to the tone. Some pianists prefer the brighter, more complicated sound of lacquered hammers, while others prefer a cleaner sound, without lacquer. Over the years, tastes in tone have changed significantly; in recent years, I have had fewer requests for a bright tone.
Three Hamburg Steinways: Problems and Solutions
1935 Steinway D (8' 11¾")
This piano, which is in the private residence of a professional pianist who plays major repertoire, was rebuilt in the 1990s. The pianist complained that the repetition was too slow, and that the piano lacked good tonal presence in the treble. Another technician had added lead weights to the rear section of the keys in an attempt to make the action repeat faster, but this only made it more sluggish.
When inspected, the instrument turned out to have friction and geometry problems that had to be addressed before the action could be regulated and weighed off. When the piano was rebuilt, new action parts were installed, but they had become compressed and dirty in the 17 years since, and friction had become a major problem. In addition, the replacement action parts available when the piano was rebuilt had not been of the size originally installed, which created the geometry problems. Finally, the plate — and therefore the strings — had been reinstalled a bit too high, making regulation even more challenging and creating repetition problems. However, there was almost no hammer wear.
Given the good condition of the hammers and the high cost of replacing parts, I decided that in this case it would be more cost-effective to modify the existing parts than to replace them. First, I filed the hammers, repinned most of the action centers, cleaned and polished most other friction points and contact surfaces, and removed the extra lead weights from the keys. Then, to correct the geometry problems and compensate for the excess string height, I raised the action stack and made small changes to the contours, heights, and positions of some of the action parts. Finally, I regulated the action and corrected the touchweight.
After the problems of friction, geometry, regulation, and touchweight had been solved, I slightly repositioned the action relative to the treble strings, to get a more optimal treble tone. At the same time, the owner removed a rug from under the piano, which gave me more volume to work with. Interestingly, in addition to the above, the solution to getting more treble tone was to needle the hammers. This counterintuitive approach increased the flexibility of the hammer shoulders, which produced a rounder tone and boosted the body of the sound. The result was a more singing treble, a much more colorful tenor and bass, and greater dynamic range.
1984 Steinway O (5' 10½")
This Model O had had a succession of technical changes made by a series of technicians in attempts to address action problems that were primarily the results of age and heavy use. The main complaints were that the action was very uncontrollable and heavy, and the sound harsh.
Originally, the owner had complained about the action to Technician A, who replaced the hammers, shanks, and flanges with parts made by another manufacturer that were not suitable matches to the original. This technician had noticed that the hammers were worn, and ascribed the customer's complaints to that, even though the customer had at first had no complaint about the tone — he was concerned about the feel of the action, which, it turned out, was dirty, worn, and had not been regulated in 28 years. But Technician A never addressed the friction or action-regulation problems, so, despite the new parts, the initial problem persisted. The customer, still not happy, called Technician B.
Technician B reinstalled the original parts (which the customer had kept), but, like Technician A, did not address the friction and regulation issues. When the customer complained to a third technician of an inability to control the piano's volume, Technician C tried to remedy that by hardening the original, 28-year-old hammers. I then arrived to find the worn, original hammers, shanks, and flanges screwed back onto the action, the action far out of regulation, and the hammers hardened beyond retrieval.
The primary source of the problems was friction in the action — so much friction that the piano was very difficult to play at all — and the customer's inability to control the volume was aggravated by uneven regulation. I salvaged many of the original action parts by minimizing the friction, but had to replace the hammers, shanks, and flanges because the hammers were now too hard to be voiced and the hammershank knuckles were worn.
This incident highlights the need for good communication between technician and customer, and the need for the technician to investigate beyond the customer's initial complaint, in order to find the ultimate sources of the problems.
2010 Steinway D (8' 11¾")
This nearly new piano belongs to a university. The very astute pianists there wanted a bigger sound in a portion of the tenor area, and complained that the piano was a bit unresponsive, its action sluggish, its tone too mellow.
It turned out that this lovely instrument was just fine. What had happened was that it had experienced the normal settling of new action parts that occurs with every new instrument, and needed only the very minor regulation touchup that is entirely normal and predictable for a new piano that has had little use. The hall in which it was kept was a bit humid, which not only made the hammers swell slightly, muting their sound, but had slightly unseated the keyframe. Remedying what had been described as a lack of power in the tenor section required only a very minor reseating of the keyframe.
Following a thorough regulation in which I made only minuscule adjustments, I lubricated the key pins to reduce friction, and ironed the hammers to tighten their surfaces enough to restore the tone. With the tone and power restored, it was easier for the pianists to produce the sound they wanted, which had the psychological effect of eliminating the action's perceived sluggish lack of response. What had been presented as a complaint about the voicing of a small section of the tenor had turned out to be, for the most part, problems of regulation and humidity. After I'd touched up the fit of hammers to strings, evening out the tone in the first treble section required the very slight needling of only a few hammers.
When pianists praise a piano for being even and smooth, with effortless control, these qualities are the results not only of a quality action correctly installed, but also of hours, days, or weeks of technical attention paid, in both the factory (or rebuilding shop) and in the field, to realize the instrument's potential. As the above examples illustrate, the real problems and the true potential of a fine instrument are not always obvious, and even the best pianos can play poorly when badly maintained or rebuilt, or when their problems are misdiagnosed. A purchaser armed with this understanding, and with the support of an experienced piano technician, is in a position to recognize otherwise excellent instruments with correctable problems that others might pass up. As an informed owner, you can communicate your complaints about action and tone more clearly, and you'll be in a better position to evaluate whether or not your technician can satisfy your piano's technical needs.
As the owner of the 1935 Steinway D wrote to me after several weeks and many visits to correct its problems:
"I think many pianists live with the frustration of never quite playing the way they really hear the music, never realizing that things can be better. You really can sing at the piano, and the instrument can be truly miraculous if you don't have to fight it. As a result of our collaboration over the past few months, I have been able to develop my tonal palette considerably."
Over the past 35 years, piano technician Sally Phillips has worked in virtually every aspect of the piano industry—service, retail, wholesale, and manufacturing. In her role as a concert-piano technician, she has tuned and prepared pianos for concert and recording work in such venues as Town Hall, Alice Tully Hall, and the Kennedy Center, and for such orchestras as the Cincinnati Symphony, the BBC Concert Orchestra, and the Vienna Philharmonic. At present, Phillips lives in Kentucky and works throughout the southeastern U.S. She can be contacted at [email protected].