David,
In this particular piano the whole scale were changed.
If I should smooth out just the bass/tenor part and keep the steel strings as they are, I would change the whole bass in another way.
Anyway, it is not easy to talk about this. It all ends up in what we are hearing.
If those who are into this scale posting were gathered around some grands we could start talking about what we find good or bad.
David Love <davidlovepianos at comcast.net> skrev: The other issue is that the changes made, that we were talking about originally, were to blend the bass better with the tenor. That actually required a slight lowering of the tensions. Whether this would break strings or not (not to mention the increased load on the plate) it seems that problem of blending would be exacerbated. With such high tensions, I also wonder what would happen to the balance of partials in this section. It would seem that it would produce an even more weakened fundamental and quite powerful upper partials—even more so than the original. Not something I would aim for personally.
David Love
davidlovepianos at comcast.net
www.davidlovepianos.com
-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Aras
Sent: Tuesday, April 03, 2007 7:25 AM
To: Pianotech List
Subject: SV: Re: Steinway B Scale Conversion
OK, so here are the actual tensions in % from the breaking points in the rescaled B starting from A0 > A2
73, 75, 76, 76, 76, 75, 75, 76, 64, 66, 68, 71, 72, 73, 75, 76, 76, 78, 77, 76, 58, 63, 70, 65, 70.
And the % from the original B. Starting from A0 > E2
37, 40, 45, 47, 55, 53, 54, 56, 49, 49, 47, 48, 47, 47, 48, 48, 48, 48, 46, 47.
And here are the tensions in Newton/string:
1533, 1521, 1476, 1425, 1970, 1290, 1301, 1309, 902, 926, 947, 949, 965, 967, 964, 968, 970, 947, 938, 925, 922, 926, 932, 952, 937.
And tensions in Newton/string original:
1156, 1107, 1088, 1139, 1160, 1128, 1140, 1066, 734, 742, 649, 659, 657, 623, 637, 638, 609, 604, 552, 570.
As I wrote, no strings have been broken after more than 10 years of hard playing.
John Delacour <JD at pianomaker.co.uk> skrev:
At 5:02 pm -0500 2/4/07, Ron Nossaman wrote:
>>Let others calculate the tension of that scale and see who they
>>think has the more reason.
>
>I certainly wouldn't spec a scale like this, but...
>
>>The lengths for the 20 notes on the bass bridge are printed below.
>>When I see a bass scale that requires the wire for the greater part
>>of the scale to operate at over 80% of the actual breaking strain,
>>as high as 86% for one note, I know I'm looking at a recipe for
>>disaster.
>
>I show C-1 at 68% and 377lbs as the highest. What are you using to
>determine these percentages?
In practice a No. 21 core with covers 70 and 170 will end up at
roughly 5.54 mm depending on who makes the string and how good a day
he's having. That gives a tension of roughly 351 lbs. I have the
breaking strain of mwg 21 as 405 lbs. so that gives 87%. Paulello
has 414 lbs as the breaking strain of his No. 21 'M' (modern) wire,
so very close to the figure I have always used. Juan Más Cabré
gives (245 kg) 540 lbs for No. 21
"modern wire" and 470 lbs for his own, neither of which figures I
find in the least credible.
It is clear from this discrepancy and from a recent difference in our
figures in another thread that you have a list of breaking strains
considerably higher than mine, which I obtained from the manufacturer
many years ago and which have served well for the bass string
manufactory for as long. I never intentionally make a bass string
that exceeds 70% of the breaking strain as per my list. Since I am
human I occasionally punch in the wrong length or something and
inadvertently send out a string (or even, most memorably just before
last Christmas, a whole set) that is over-tensioned. My pocket and
my serenity begin to suffer quite soon after as the customer's new
strings begin to go bang.
I am interested to know where you got your list of breaking strains
which differs so greatly from mine and Paulello's. Please send me it
off list and let me know its origin. Yours seems to be similar to
Más Cabré's, which, as I have said, I do not regard as serious. With
very few exceptions among the hundreds of calculated bass scales I
have, piano makers keep within the limits I have stated and models
that exceed them have problems with breakages, for example the
Bösendorfer I mentioned earlier. Schiedmayer & Soehne and Grotrian
are two makers a few of whose models have grossly exceeded the
limits. One string I always recognise when it comes in the post for
replacement -- I have lost count of the number of these I have
replaced with scaled down versions --is note 13 on the Blüthner 6'3"
style 6/7. The original string is 126.1 cm. long and has a No. 19
core with an overall diameter of 3.38 mm. That gives a tension of
roughly 280 lbs. and requires the core to be at 82% of breaking
strain. This string (and the one below) will _always_ break even
though these Poehlmann wire used was far superior to what we have now.
I should add that a greater margin is required for covered strings
than for plain wire owing to the eye. I know it is possible to
exceed the 70% limit for plain wire strings and the extreme treble of
many pianos does so, not to speak of several "long scales" I could
think of, Schiedmayer again being a foul offender.
JD
---------------------------------
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