When confronted by tone problems, many piano technicians seem overly anxious to find a quick remedy by using voicing needles or lacquer. Both needling and lacquering are important elements in the over-all voicing picture; a skilled technician must know when and how to use voicing needles, as well as how to prepare and use lacquer solutions for hammer hardening. The point is this: both these methods are ultimately destructive to hammer felt, and shouldn’t be used until all other possible solutions have been explored. What are some of the things to check before we begin to needle or lacquer?
A. Before thinking
about voicing we must make sure the piano is well tuned. We all have had
clients comment upon the remarkable change in tone or volume after a good,
solid tuning. A major pitch change will most assuredly change a piano’s voice,
so tune it first. As part of our preliminary tuning procedure we must consider several
areas which can affect tone:
1) Tighten all plate
screws.
2) Seat strings
properly, using a wooden or brass tool to tap them down on bridges, aliquots,
duplex bars, and counter-bearing bars. This can clear up false beats, and clean
up a muddy sounding tone.
3) At this time, check
and, if necessary, correct the tuning of the duplex scale - if the instrument has
one. You may notice a brighter, louder tone when the duplex strings properly
reinforce the harmonic structure of a given note.
4) We also double check
the location and tension of stringing braid. A minor point, but one which can
either add or eliminate high partials without using needles.
B. Next, we consider
the role of proper action regulation in piano tone-building. Perhaps this is an
obvious point, but sometimes we overlook regulation problems and are quick to
blame hard or soft hammers, old strings, etc., for tonal problems. Some areas
of regulation seem to have a greater effect on the tone we hear:
1) Of primary
importance in this area is the bedding of the keyframe. This foundation for all
our regulation has a very direct influence on what the artist hears, both
physically and psychologically. Generally, an improperly bedded keyframe will
cause loss of power and consequent loss of tone.
2) Another major item to check here is the
proper hammer striking point, especially in the high treble. Many a hammer has
been unnecessarily hardened, when the problem was really an incorrect strike
point. Check by experimenting- results here are immediately obvious.
3) Travelling of
hammers and shanks can affect tone, so do this work carefully.
4) Of utmost importance
is the actual hammer-string contact point: each hammer must hit its strings
squarely and simultaneously. Space the hammers to the strings. File the hammers
if necessary to remove dead felt, and to provide a perfectly level surface at
the strike point. Later, we will discuss filing to bring up volume and
brilliance.
After checking that the
hammers are level, we check for level strings. String levelling is much over-looked,
both by manufacturers and technicians. Here is an area that can dramatically
improve tone. The symptom of an unlevel unison is an unclean, almost buzzing sound.
It can also seem like a false beat, and can make tuning difficult.
Check all unisons by
pulling the hammer up to the strings and blocking it there. Use either a hook
to support the shank from the bottom, or use the method of pushing up on the
bottom of the jack and not allowing let-off to occur.
When the hammer is
blocked in such a fashion, the strings are individually plucked. It is
immediately apparent if one or more strings is not level. The high strings will
sound, while low strings will be deadened by the hammer. Carefully lift all low
strings to the level of the high strings. Use a tool available from supply
houses (string lifter) or make yourself a stringing hook using heavy gauge music
wire epoxied into a handle of some sort.
In string levelling we
are actually pulling up and slightly bending the wire near the agraffe or cape bar.
This technique is easily learned and is an important part of pre-voicing. (An
added bonus of level strings comes when we regulate dampers- especially in fine
adjustment of the tri-chord wedges.)
C. The piano can be
well tuned and properly regulated, but still lack volume or brilliance. Don’t lacquer
yet. If there is plenty of felt on the hammers, another filing can increase
tone quickly. Getting down closer to the hammer molding, the layers of felt are
harder and can create a more brilliant tone. This is especially useful to bring
up sound in the high treble.
Some manufacturers
count on the technician to remove...
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