A Reproducing Piano's "Voice"
By Terry Smythe
Recently in an exchange of email, Doug Rhodes posed the following question about a Weber Duo-Art owned by a mutual friend, that is in need of some help to bring its "voice" into some degree of harmony with a relatively small living room...
> He and I regulated the expression accordion on his Weber
> Duo-Art a few months ago using a dial gauge. Definitely an
> improvement over what it had been (which was way too loud), but I
> want to experiment on it this summer to try to further compress the
> dynamic range. The piano is a very good Weber, but it is small and a
> bit brash, and it is in a relatively small room. I'd like to find a
> dynamic range that represents how the recorded pianist would have
> played _that_ piano in _that_ room, not a nine-footer in a big hall.
> I think that part of the problem I have with his piano is that the
> Duo-Art coding is aimed at a larger piano. The test roll really
> functions quite well, but some classical rolls are just too soft and
> wimpy on pianissimo passages, though there are no drop-outs.
> Similarly, the fortissimo passages are still a bit overwhelming. The
> softer playing is the greater concern now, as it just doesn't sound
> very realistic. I'm ready to depart from the 1/8", 1/4", etc. spacing
> of the accordion in favour of some experimentally arrived at spacing
> that *sounds right*. I'm pretty ignorant of the theory behind the
> expression coding on either the Duo-Art or Ampico rolls, but I _do_
> know what real live piano playing sounds like, so trial and error may
> be the method used.
> Any ideas?
I too once had a 6' Mason & Risch Duo-Art in my small living room, and it too was way too loud. In my experience, it is much more difficult to tone down a big Duo-Art than an Ampico. However, by using a mix of tools and techniques, I was able to bring it down to a tolerable level. Some things to consider:
1. I believe the Duo-Art was always intended primarily for fine
quality performance of classical music, while providing reasonably
good performances of the pops and ballads. Ampico on the other
hand was I believe intended for average fireside entertainment in
average homes where contemporary music of the 20's was dominant, but
when called upon to do so, could do a reasonably good job with
classical music. Classical music rarely does well if the system is
choked in some fashion, therefore should always be running with the
full range of dynamics and power.
2. A brilliant, brassy piano is usually telling me it's hammers need to
be softened somewhat. I've done a fair amount of voicing with my
own pianos only, I would not attempt to do so with somebody else's
piano. On my Mason, I replaced the hammers, specifying I wanted to
soften the voice of the piano somewhat, hoping for that elusive,
sensuous Mason & Hamlin sound. The result came close, but only
after extensive voicing. I worked at it for weeks, with results
not too satisfying. In desperation, I resorted to what seemed like
drastic measures, squeezing the hammers with parallel-jawed pliers
either side of the crown, about 3-4 passes single squeeze at a time
until I detected noticeable results. To my surprise and delight,
the piano's total voice did noticeably improve for that small living
room. I don't believe I overdid it.
3. A big Duo-Art will absolutely not play softly if piano regulation is
out anywhere. An Ampico for some reason is a little more
forgiving. Many years ago, I was fortunate enough to acquire a
Piano Service Manual for a contemporary grand piano, which provides
pretty good guidelines for grand regulation. It has been a great
help to me over the years, and I now do my own grand regulation.
4. The previous owner of my Mason had not restored the valves, but had
recovered the note striker pneumatics. I finally had to drop the
stack, and redo the valves and I found the valve leather facings
quite badly deteriorated. I also found that the pneumatics had
been recovered with a cotton based replica of the old original
fabric. I believe that fabric is still being sold today, but in my
judgement it is too thick and heavy for the sensitivity needed for a
reproducing piano. I recovered the pneumatics with "Shultz" cloth,
silk based, extremely light and super flexible. Quite costly and
difficult to handle until I discovered the Dritz Cutting Wheel.
The combination of new valve facings, valve travel reset, bleeds
cleaned out thoroughly, and the Shultz cloth made another noticeable
difference. That piano will play tolerably at just over 4", but is
reliable at 5" at which I left it.
5. About 20 years ago, Bob Taylor in Philadelphia did some
experimenting with the springs on the Duo-Art expression box, and
found he was able to get an improvement in soft performance with
different springs. I bought 2 pair from him at the time, installed
one pair in that Mason, and once again, yet another improvement in
soft performance. I do not know in what way these springs are
different, for I am not an engineer, and Bob never did reveal what
he ended up with. From an engineer's viewpoint, this is something
worth exploring. This aspect of the Duo-Art has never been
documented, at least not in the AMICA Bulletin, of which I have a
full 32 year unbroken set.
6. Something I've wondered about, but have never tried is to tune the
piano somewhat below A440. It seems to me that this might
additionally help bring a piano's voice into harmony with its
location. I do not have a "tuning ear", so have to resort to an
old tube type "Strobotuner", which gives me reasonably satisfying
results for me here at home. When I take a piano out for a public
performance, part of the sponsor's obligation is a professional
tuning job on stage.
> You mentioned de-tuning the piano from A-440 in an attempt to tone
> down the instrument. I would think you'd have to drop the pitch fairly
> considerably, perhaps a half-step or more before you'd really begin to
> affect the loudness, though you would certainly sense a change in
> tone. The de-stabilization of tuning, and the work it would require to
> re-stabilize at A-440 would not be worth the experiment, in my
> judgment.
These are a few considerations that might be considered. I am not a professional piano technician, I do not do work for other people, only my own instruments. And I am not an engineer, just a self-taught technician. Much of what I have expressed here might not stand the test of an engineer's sharp pencil. Perhaps others on this list might wish to expand on these and/or other considerations. This is one of the reasons why I enjoy this list so much, where I feel the freedom to expose my ignorance in dignity and emerge a little wiser.
In principle, much of what I've mentioned here is what I do with all the grands I own, as a ground-up restoration from rough basket-case. My 1935 George Steck Ampico A/B currently in my living room responded very well to this overall treatment, set at a dynamic range of 4.5" to 20" in my living room, and to 35" when taken out for public concert performances.
Curiously, this particular system originally came with an B drawer, B stack, and A everything else. The expression units are abbreviated with no regulators, only a single crescendo, and no compensators or equalizers. I suspect it was likely assembled out of left-over parts following the Aeolian/American merger. I've recently added a second crescendo to bring it up to "A" expression specs. It's performance is quite dramatic, guaranteed to provoke leaky eyeballs. Emotional reactions are quite common in its presence.
Any other thoughts on this intriguing subject?
Regards,
Terry
Home Page: http://www.mts.net/~smythe
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(Message sent Mon 6 May 1996, 19:57:07 GMT, from time zone GMT-0500.) |
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