Designs on a grand scale

[Overs Pianos]

Hi Alan and all,

>Ron Overs wrote;
>
>"I look forward to the possibility that within 20 years a majority 
>of pianos might use scales with deviations similar to the upright 
>scale shown above, or better. With longer pianos it is possible to 
>design a scale with even less tension deviation than the upright 
>scale shown above."
>
>Just curious, for what size grand would this scale design be appropriate?

This scale length would be most suitable for a grand of around 6' 
(183 cm). The longest speaking length in the bass is 133 cm, with a 
150mm back scale. Some contemporary designers are using 140 cm for 
their 185 cm pianos A1 speaking length, but these instruments have a 
slightly restricted low bass, since there isn't room for a 
satisfactory back scale when this speaking length is used in such a 
short piano.

The lowest treble-bridge note on this scale would fit into a 157 cm 
grand, but the low bass would be too long. However, the scale could 
be adapted for a 157 cm instrument by shortening the lowest bass 
speaking length to around 116 - 118 cm and leaving the highest bass 
note at its original speaking length. This will preserve the smooth 
crossover between the treble and bass while using a shortened low 
bass which will fit in the case. A set of log style speaking lengths 
for the bass bridge can be derived using a multiplier factor of;

*(L/l)^(1/(n-1))

Where;

L = the speaking length of the lowest bass note
l = the speaking length of the highest bass note
n - the number of notes in the bass section.

So, lets say we've got a speaking length at A1 of 135 cm, just to use 
an industry standard for many 6' grands. Lets say the bass break note 
has a speaking length of 94 cm at note Bfl26  (eg. Yamaha G3).

Substituting the figures for the above speaking lengths into the 
above multiplier equation we get;

=(135/94)^(1/(26-1))
= 1.014584831

You can now take this multiplier and create your log-style speaking 
lengths from Bfl26 to A1.

Bfl26 = 94 cm
A25 = 94 * 1.014584831  =  95.4  cm
G#24 = 95.4 * 1.014584831 = 96.8 cm
. . . etc. all  the way to A1 at 135 cm

Scaling is a whole lot of fun once you learn to manipulate a spreadsheet.

However, I would never design a 6' piano with a break at note Bfl26. 
But I have used it as an example here, since it has been the default 
break point for many contemporary 6' grands.

>  I've wondered why when over 100 years ago Steinway had a transition 
>bridge design in their model (short) A was this abandoned.

I know Alan, its incredible. Way back then, S&S were doing what a 
number of contemporary scale designers are now advocating, yet they 
gave it up. I don't believe the concept was abandoned because it 
didn't perform. I believe it had more to do with the cost of 
execution.

>  Has anyone ever contacted them to ask why or have they not employed 
>scale designers since?

I once asked Mr Max Mathias (former head of design for Steinway 
Hamburg) this question, but I didn't receive an answer which I felt I 
could believe. At the time (some time around 1988-89) Mr Mathias was 
visiting Sydney. I was showing him some images of a model M that I 
had rebuilt with a tenor bridge. He didn't seem to be impressed with 
my work at all. He said that Steinway used to do this sort of thing a 
hundred years ago, implying that I had lost my way by incorporating 
such an outdated idea into a modern grand piano design, which had 
sort of moved on from such 'archaic' practices. I remained 
unconvinced then and I remain unconvinced today. I believe that S&S 
were on the right track with their transition-bridged short A. These 
pianos respond very well to a remanufacture by changing the tr-ichord 
covered notes on the transition bridge so that they are all  bi-chord 
covered, and beefing up the soundboard ribs so that they can actually 
withstand the downbearing load under which they are placed. Oh, and 
the bass suspended bridge has to go, preferably with note A1 
shortened back to 135 cm from its original 140 cm. Notice also that 
the short A, with the tenor bridge, breaks at D30 on the long bridge. 
This is a very intelligent place to break on a piano of such length. 
The later iterations, where all the bi-chord covers are mounted on 
the same long bridge, heading on down from C#29 to a F21/E20 cross, 
wouldn't hold a candle to the earlier concept.

I believe that whenever one encounters an instrument which has 
covered notes on the low end of the treble bridge, the proper 
factory-fix for these instruments is to redesign the plate and move 
the break up to include the wrapped notes in the bass section. In 
this way it becomes possible to incorporate a shortened speaking 
length for the first covered note, relative to the last plain wire. 
This is necessary to achieve a smooth scaling transition between the 
lowest plain strung notes and the first covered bi-chords. I realise 
that some makers use wrapped tri-chords when crossing from plains to 
covers, but this is also unnecessary, adding further inconvenience 
for the tuner with an increased risk of wild unisons. Its also a 
whole lot more trouble for the string winder. In short, it presents 
more trouble for everyone with no tangible gains that I can see.

Of course, redesigning a plate is beyond practicality for a 
rebuilder, but a tenor bridge will achieve the same outcome, and its 
doable. There are several on this list who have made the 
incorporation of a tenor bridge a routine procedure. The 
tenor-bridge-operation for the specialist grand rebuilder is the 
triple bypass for the specialist surgeon. Both have become routine, 
and both give new life to old hacks.

>  And speaking of designs American, what on earth were they thinking of here?
>
>

Perhaps the designer was dreaming of space shuttles as he doodled 
with spatula and clay.

Ron O.
-- 
OVERS PIANOS - SYDNEY
    Grand Piano Manufacturers
_______________________

Web http://overspianos.com.au
mailto:ron at overspianos.com.au
_______________________
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