1 string, 2 strings, 3 strings or more

[Delwin D Fandrich]

----- Original Message -----
From: "John Delacour" <JD@Pianomaker.co.uk>
To: <pianotech@ptg.org>
Sent: September 18, 2001 5:55 PM
Subject: Re: 1 string, 2 strings, 3 strings or more


> At 11:54 18/09/01 -0700, Delwin D Fandrich wrote:
>
> >While I acknowledge that many pianos do have the drop-off you mention, it
is
> >certainly not desirable. Most of these (obsolete) scales do much better
with
> >several bi-chord wrapped unisons in the tenor section ideally placed on a
> >separate bridge.
>
> Interesting.  On the one hand you bemoan (as I do) the characterless
> uniformity of modern piano tone and on the other you talk of "obsolete
> scales" (which I think would include all Steinway's grand scales?) and yet
> you talk of an ideal solution lying in a transition bridge, which was
quite
> common in the 1870s - 80s and universally discarded in Europe before the
> turn of the century, roughly speaking.  I'm not disagreeing with you but
> I'd like to know what classes as an obsolete scale in your view?

To pick just one example the S&S B scale is, in my opinion, an obsolete
scale. C-88 varies between 47 mm and 49.5 mm which is some short by today's
standards. The bass/tenor break (at E-20/F-21) falls to low in the scale for
a piano of this size resulting in either an excessively low string tension
(approx. 120 lbs, depending on the bridge location) or excessively large
diameter strings to keep the string tension in line with the higher scaling
(it would require a 0.053" string to keep tensions in the mid-160 range).

The only practical solution without changing the plate is a third or, as you
call it, a transition bridge. (Good name, that.) Given a transition bridge,
the upper bass bridge
is still placed such that the bi-chords are considerably shorter than I
would like to see them.



> For
> example, would Klauss Fenner's ubiquitous scales be classed as modern and
> therefore productive of a tone quality that is more desirable than that of
> the great pre-1914 pianos?

I don't know enough about Mr Fenner's scaling practices to comment on them.
I have, of course, looked at them and they seem pretty traditional--that is
obsolete. And the small grand piano scale described in his latest book
appears to have some (again in my opinion) pretty serious problems. But I've
not really done any in depth analysis of any of them. Perhaps others would
like to comment.



>
> As to the fall-off in tension at the extreme treble, obsolete or not, I
> would always aim for this; not to do so is asking for breakages in view of
> the doubtful quality of modern wire. To expect a No 13 wire to support
> 170-180 lbs. is, I think, optimistic, and I would set the length of note
88
> at 4.8 - 5.0 mm. the tension to rise with the gauges to an average 165-70
> lbs for the remainder of the steel scale.

I expect you mean cm in the above. And I disagree. Many, if not most, modern
pianos are running upwards of 52 mm at C-88. Many are in the 54 to 56 mm
range with no long-term undesirable side effects. My own standard is C-88 =
54 mm.



>
> As to the lowering of tension at
> the other end of the long bridge, you seem to be saying this is a sign of
> obsolete scaling and that seems to mean that most modern 6' grands have
> obsolete scaling,

Yes. That is a good summary of what I am saying.



>
> ...since the only ways to avoid this are a) to shift notes
> onto the bass bridge, which would cause even worse problems

Why do you say this. I designed the Walter 190 grand with a 27 note bass
section. When properly built the bass/tenor transition is essentially
transparant. Our own 122 vertical piano has a 32 note bass section and
several roomfulls of piano technicians could not reliably pick out the
bass/tenor transition.



>
> or b) to
> provide a transition bridge as you say, which  has not been considered
> desirable for over 100 years -- and that gives this solution  a pretty
good
> seal of obsoletion, even if it's a good solution, which I don't
> doubt.

Well, an idea can be done well or it can be done poorly. All of the early
transition bridge designs I've seen--and that is certainly not all of them
by any means--shorten the strings way to much. And many of them, if not
most, transition to tri-chord wrapped strings--something I will never
willing do.



>
> I've seen uprights with 5 bridges, all at different levels..
> there's something that _certainly_ won't return!

No it won't. Nor should it. My latest 200 cm design uses a transition bridge
although the scale only has one break. That is, the tenor/treble bride is a
true semi-log scale from C-88 down to the transition between the tri-chord
plain strings and then it transitions to the bass (bi-chord wrapped) which
is also a semi-log progression. (I hope that makes sense--it's easier to
draw!)



>
> >So far I have found no rationale for the use of tri-chord wrapped strings
on
> >either bridge on any scale of any length.
>
> Presumably the rationale is not only to aid the transition but to produce
a
> certain quality in that section of the piano.  One of my favourite
> instruments of all time is the old (ca. 1899) Steinway 6' grand.  The bass
> bridge and scaling on this piano up to note 20 are almost identical to the
> 6'2" model A that succeeded it, but as you know there is then a transition
> bridge holding two covered bichords and 7 covered trichords.  The A has
> only two bridges with 5 covered bichords on the long bridge.  There are
> other differences of course, not least the fine quality of the soundboard
> on the older one, but personally I find the 6' piano magic and the 6'2
> relatively uninteresting.  It's a while since I have had my hands on
> either, but I think this is a case where covered trichords actually served
> a purpose and were not a mere fudge.  August Förster until quite recently,
> and maybe still, used several trichord break notes on their uprights but
> this always struck me as either a bit of show or a necessary fudge to hide
> bad scaling.

But this practice is always a fudge. There is no way to get this transition
to work as well as a simple, well-designed transition from tri-chord plain
to bi-chord wrapped. One of the problems all of these early builders had to
cope with was the excessive length variations they built in at the
transition. As to why they did this I've no idea.

Del