At 13:32 -0500 24/3/10, Mike Spalding wrote:
>1. Producing identical sound loudness probably requires equal
>energy transfer from the hammer to the string. Energy is not
>equivalent to momentum. Energy is mass times the square of the
>velocity.
>2. To ask the question the way it has been phrased, assumes that
>the motion of the key is the same in both A and B. I think this is
>unlikely, as the inertia seen by the finger at keystick B is
>significantly less than in A, so the same pianist will produce
>different velocity profiles in the two keys.
>
>3. A slower heavier hammer transferring the same amount of energy
>to the string will probably have a different dwell time at the
>string. Will that affect how much of the hammer's kinetic energy
>actually gets transferred to the string? Not a simple answer,
>since we're talking about energy distributed across a spectrum of
>partials. Perhaps you could equalize dwell time through voicing.
>Perhaps you'd rather make them sound as similar to each other as
>possible through voicing. In either case, it's starting to look a
>lot like apples and oranges.
Here's an interesting anecdote. The other day I received back from
Abel the hammers from a fine BlŸthner upright, recovered in the
"natural" felt. Since it has overdampers, I had assembled the lower
action in preparation for the return of the hammers so that all I
would have to do is attach them to the installed flanges and tighten
the butt plate.
In order to get a feel for the brightness of the hammers I did a
little toning and papering on all the Cs one by one. When it came to
C64 I mistakenly picked up C76 from the tray, prepared and fitted it.
The moment I played the note the most awful sound came out and it
took me a few moments to realise what caused it. Of course I have
experienced this before, but before I have always been aware of the
reason. This time I was quite shocked.
Now no matter how hard I hit that note with the too-light hammer I am
never going to get the fundamental and low partials in anything like
their proper proportions and the note is always going to sound like a
tin can. By getting the momentum the same as it would have been with
the proper hammer, that is by increasing its velocity to compensate
for the reduced mass, I may well get some sort of equivalent volume,
but the quality of the tone will never be anything like equivalent.
One of my favourite grands is the Lipp. Those of the best period
were made with a very light action. Although they are always good
with the original weight of hammer, I have found that by increasing
the weight of the hammer in order to increase the tough weight there
is a marked increase in the fullness of the tone, and this must be an
experience common to many of us. With the Lipp it is an improvement
gained at very little expense, since the action originally would be
considered too light by most players.
By contrast I have seen old model B Steinways restored at the
Steinway shop in the 1970s using the heavier hammer, compensated for
by a ton of lead in the keys, with the result that the pianos are so
sluggish as to be virtually unplayable. It may be that the heavier
hammer produces a better tone (doubtful in this case) but unless the
action ratio is altered it is impossible to achieve acceptable
results.
JD
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