From our Piano Tech, James Carney:
Brian Drye asked me to write a description on the work I did on the IBeam piano last week, and after doing so, I was surprised at the length of my report. I was going to whittle the whole thing down to several “sound bite” size sentences, but then I realized if I did that, lots of little details would be edited out. The fact is, pianos are big, beautiful, complicated instruments that remain enigmatic to the majority of pianists, and this recap might help a few folks develop more of an appreciation for the technical aspects, so after further thought I decided to keep the loquaciousness fully intact. (My apologies to anyone who has an aversion to that!)
Ibeam is a special venue for lots of reasons, but perhaps one of its greatest attributes is the large piano it offers to both player and listener: a very fine Schimmel model 208 semi-concert grand. The 208 means 208 centimeters in length – approximately 6’10”
Schimmel pianos are made in Braunschweig, Germany, and like most acoustic pianos from Europe, the scale design is excellent and the quality of construction done at a very high level. Scale design refers to the architecture and design of three crucial elements of any particular piano: the placement and terminations of the strings within the cast iron plate, the position of the bass and treble bridges, and the diameters, lengths, and tensions of the strings themselves.
This particular Schimmel was made in 1991 and had received heavy use over the last twenty years, but very little maintenance. The first time I played a gig at IBeam a few years ago I was immediately struck by how little sound was coming out, no matter how hard I dug into the keys. For an instrument of this size, that was a red flag to me that something was amiss; The key rattling was also annoying, and I could see that several regulation parameters were way off, making the piano difficult to play quietly – as well as difficult to play loud. I mentioned to Brian that what it really needed was several days of TLC.
Last week we were finally able to lavish that TLC on the Schimmel and here’s the work that was done:
In mid-December, I installed a humidity control system to stabilize the soundboard and other parts of the piano. NYC is one of the harshest environments anywhere in the world for pianos, as we experience humid summers and extremely dry winters due to the high amounts of heat we tend to prefer. It’s not uncommon for NYC building interiors to go from 70% RH (relative humidity) in summer to 20% RH in winter: Not good! The magic number we want with pianos is about 45%. So the “Dampp Chaser” system we put in will help preserve the instrument, the regulation, and all future tunings. We waited a few weeks after installation before doing any work so that the piano could acclimate to its new “equilibrium moisture content” – which is the level of moisture in a given piece of wood at which it will lose or gain moisture at exactly the same rate.
I replaced all of the cloth bushings in the keys, both balance rail and front rail – 4 bushings per key. I use special cauls that are exactly the same size as the keypins so that the fit is as perfect as it can be, without any binding, excess friction, or sloppiness. The keys are removed from the keyframe and placed onto 2 special clamps that hold 44 keys apiece, making it easier and safe to handle the delicate keys, and to allow easy “flipping” as access to both sides of the key is necessary. Old worn bushings are carefully soaked out with scrap felt wedges that have been dipped in hot water to loosen the old glue, and mortise sizing cauls inserted immediately afterwards to dry overnight. This is a step I always do when rebushing, as the sizing creates a perfectly shaped wooden mortise, making installation of the new bushings much more uniform and precise. I used high quality English bushing cloth and traditional hot hide glue, granules mixed with water in a covered glue pot that keeps the glue at a consistent 140-150 degrees for the duration of the job. This is the same method that pianomakers have used since the 1800s, and it works beautifully.
With that accomplished, I replaced all of the cloth front rail punchings and felt balance rail punchings with highest quality materials. Punchings sit at the bottom of the keypins, under the keys, and they deteriorate with age, hard use, humidity changes, moths, bugs, airborne grease, etc.
so it’s often best to replace these crucial parts that will feel the brunt of hundreds of thousands of future downstrokes from each key. Once I did that, I was ready to square and space the keys for a consistent and even keyboard – a very important aspect of regulation so that tactile senses are optimized for the pianist.
The hammers were the next factor to deal with: These hammers had deep string cuts, they were flattened at the strike point, and many had been misaligned with the strings for years, making good tone production and a good regulation impossible without a complete reshaping. Some hammers were clicking due to weak glue joints between shank and head, which I repaired. One hammer head had popped off its moulding in the bass, making that note weak. I repaired it using a clamp, glue and a cable tie inserted through a hole drilled in both the wooden moulding and felt; a neat trick that another technician shared with me last year. Once that was done, the hammers could be “gang filed” and reshaped to produce the best tone possible. These hammers had probably been reshaped once before, maybe 10 or 15 years ago, so my reshaping might be the last one possible. Next time major work like this is done the hammers will likely need to be replaced. But they still sound very good and have some years left in them…
Then I cleaned the piano, including the soundboard, plate, keybed, and action. This step took about 5 hours, which I did over a two-day period, usually while waiting for glue to dry. Dust harbors moisture, not to mention it’s nasty to breathe in when working on a piano for extended periods of time.
I also tightened every single screw I could find in the action and in the piano cabinetry itself; many were loose and some were vibrating sympathetically yet intermittently – one of the greatest challenges for any piano technician. This is when I discovered the main reason why the Schimmel had been sounding weak: it had a very loose keyframe, but this diagnosis wasn’t possible to make until all 88 keys had been removed from the keyframe, exposing the 16 or so loose keyframe screws. Tightening those screws alone made a huge difference in tone, as the keys now had greater power to transmit to the other action parts, eliminating the undesirable keyframe flex that had been robbing them of power.
Once all the screws in the keyframe were tightened it was “bedded” to the keybed by adjusting the glide bolts underneath. These had been previously misadjusted and it took some time to correct, especially because the Schimmel 208 incorporates 2 “hidden” glides into its design – that can only be accessed by lifting the keyframe up on its backside to adjust. The other glides can be tested and adjusted while tapping on the balance rail in place on the keybed, but “hidden” glides require lots of experimentation and a great deal of patience to get right. All seven glides have to be carefully adjusted to the keybed so that they each contact the keybed just slightly without knocking, yet they cannot lift the keyframe up off the keybed at all. If any glides knock or lift the keyframe then power to the keys will be lost, which results in a loss of tone, volume, and sustain. Glides are also extremely sensitive – moving the adjusting tool even less than 1mm produces a distinct change in height.
Next up was string seating: I “tapped” the string terminations at the bridge pins and hitch pins which makes a big difference in tone and\ volume, as the years of hammers colliding with them from underneath will literally push them up and away from their seated positions on the bridges.
Finally, after all of that work, the piano was ready for fine regulation and voicing.
Regulation is the process of adjusting many different components of the keys and action so that maximum power and control is delivered to the pianist. It includes aligning hammers to their respective strings, wippen alignment under the hammers, jack centering within the wippens; key leveling, setting key dip, adjusting hammer blow distance (distance hammers are from strings at rest), jack position under the knuckle, repetition lever height, letoff, drop, setting backchecks, adjusting repetition lever springs, damper timing and trapwork adjustments to the shift pedal (una corda pedal, aka “soft pedal”) and sostenuto pedal. I’m aware that much of this will sound like Greek to most non-technicians, but I mention it because it is crucial for pianists to understand why it takes so much time to do a thorough and comprehensive regulation on a piano.
Then hammers are fitted to the strings in a painstaking refinement process that ensures all three strings of a unison note are struck at exactly the same time by each hammer. If they aren’t the note will sound thin, or “out-of-phase.” This process is achieved by manipulating both strings (either by lifting or pushing down) and specific sections of each hammer (by filing away felt material in miniscule increments.) This process takes copious amounts of time but is well worth the effort, resulting in a full tone that has lots of dynamic range, a full timbre, and long, “blooming” sustain.
The icing on the cake is the process of voicing the hammers with various diameters and lengths of sewing needles, used to break up compacted felt, creating a more resilient hammer free of zings, pings, and metallic sounds. This, in conjunction with tuning, is something that never really ends while maintaining a piano. We will continue to refine and tweak the piano as it gets played in, and “burnished” from its new regulation and voicing.
It is probably fair to say that any and all pianos can be improved from their present condition – even brand new pianos – and that the work is never truly completed, but I think we got this one pretty close! I spent approximately 45 hours in total over a seven-day period, and it was rewarding to hear and feel the piano come back to the condition it likely would have been in when much newer. It was also an honor to be selected as the repair, regulating and voicing technician, and so I thank Brian Drye for entrusting me with this responsibility.
I’m now looking forward to hearing the great pianists who often perform at IBeam share their art with us over the coming year…If you get a chance to check out the Schimmel in the next few weeks please feel free to offer feedback, critiques, or other comments on the work we
I wish all of you a great 2012, filled with music, good health, peace, and