High-tension or Low-tension?

[Delwin D Fandrich]

----- Original Message -----
From: "John Delacour" <JD@Pianomaker.co.uk>
To: <pianotech@ptg.org>
Sent: September 20, 2001 2:46 PM
Subject: Re: High-tension or Low-tension?


> I gave an answer to this question in my message "Re: Standard Pitch 1870
to
> Present" of 18th September, which I think painted an accurate picture of
> the (mainly European) pianos I have examined during my career.  In the
main
> these have been pianos of good reputation (eg. most of the big name
grands)
> or pianos which had special tonal qualities that I wanted to
> investigate.

Most of the several thousand pianos I have examined have been of US or
Canadian manufacture with only a few European pianos tossed in. They have
covered the spectrum of quality levels and I've not noticed the 'pianos of
good reputation' have been scaled any better than those of poor reputation.
(Actually, this makes sense since there was a lot of design 'borrowing'
going on. The cosmetics would be changed enough to obscure the design
origins but the fundamental design would remain pretty much the same.) I
don't recall that the European instruments I've looked at were scaled any
better than were the NA instruments.



>
> In spite of our previous discussion of the 50 millimetre C88,  I have not
> found the tailing off in tension in the extreme treble to be all that
> common, tensions found in the mid treble more often being extended right
to
> the top.  In this respect I consider Steinway's lighter top to be the
> exception rather than the rule.  It's important, of course, only to
examine
> well made pianos, since careless bridge-making and positioning are
frequent
> in bad makers.

Again, most of my experience has been with NA made instruments, but in
general the speaking length of C-88 has been below 50 mm. It is my
understanding that Fenner finds a C-88 length of 48 mm to be ideal.

Please define a 'well-made' piano. I've measured the speaking length of C-88
in specific models of S&S pianos ranging from as short as 47 mm to as long
as 50 mm.



>
> Of bass scales you say "They will be up and down and back and forth
> throughout the bass, often defying any kind of logic".  I'd say that's not
> the rule, even though much bass string design in the past was left to the
> string-maker, who in England would be given a weight to work to -- if a
> maker's set weighed seven pounds and the price of copper went up, the
> astute owner would tell the string-maker to knock half a pound off the
> weight of his sets so that he could maintain his margin!  The string-maker
> at the same time would be working blind, ignorant of any scientific basis
> for his craft and working to purely empirical traditional guidelines.  One
> of these would be that string-makers don't like working with copper
thinner
> than .25 millimetres because you have to be awake, so he will persuade the
> maker to put a few more strings on the long bridge...and so on.  A slight
> exaggeration of the English scene perhaps, but I doubt it.

Well, I guess that's a logic of sorts. But it's certainly not what I would
call anything based on good scaling principles. Perhaps I should have been
more specific: "often defying any kind of mathematical logic."



>
> On the other
> hand a surprising number of bass scales preserve roughly even tension
> through the bichords with a tension curve in the singles depending on the
> length of the piano -- and I imagine the bass of your own pianos follows
> this pattern.

The bass scaling in my own designs follows a curve, they do not have a
roughly even tension. The unison tensions are lowest at A-1 and go up to a
maximum at the highest bi-chord unison. The exact numbers and the shape of
the curve depend on the length of the scale.



> Any "back and forth" is just plain lack of quality control
> -- it could never be intended in the design.

The irregularities I've measured in many of the bass scales looked at cannot
be accounted for by a lack of quality control. Especially when it is
measured in identical instruments built years apart. These things were done
to a pattern, albeit a bad one.

Del
Delwin D Fandrich
Piano Designer & Builder
Hoquiam, Washington  USA
E.mail:  pianobuilders@olynet.com
Web Site:  www.pianobuilders.com