1 string, 2 strings, 3 strings or more

[John Delacour]

At 12:54 18/09/01 -0500, Ron Nossaman wrote:


>No, I'd expect the tensions to be climbing as you go up scale, from, say,
>328lbs at #12 in an example I have at hand, to 175lbs each at #13. The
>monochord is at 54% with 0.048"core, and the bichords are at 34% with 0.44"
>cores. This hardly strikes me as unreasonable or unacceptable considering
>the original figures were 343lbs @61% for #12, and 233lbs @41% for #13. My
>choice in core diameters in this instance isn't all that huge a jump
>either, being 0.004" rather than the acceptable 0.003".

Well, we clearly have very different experience.  You say you'd expect the 
tensions to be climbing as you go up scale -- so would I through the 
singles of a 6 ft. grand but only because of the length of the piano.  In a 
concert grand I would expect the tension on the singles either to be 
roughly constant or even to fall somewhat towards the transition to 
bichords.  The only reason the tension tails off to the bottom on uprights 
and smaller grands is because we have not the length.

As to your 328 lb., I would say such a tension is dangerous on a No. 22 
core and would not exceed 307 lbs if I wanted it to last.  To achieve such 
a tension you have jumped two whole sizes.  That is fine -- I usually jump 
at least one and a half sizes -- but I would then say that your 175 lb. 
could be rather low for a No. 20 core.  At any event I would be likely to 
spin the top single for 270 lbs on a 21 core and to first bichord for 180 
lbs on a 19.5 core, presuming it's an average grand or large upright, 
though I'd need to see the lengths as well.  This is not just my crazy way 
of doing things;  Over 25 years of restringing pianos and making strings 
for the trade, I've had the opportunity of analysing the best and the worst 
of pianos.  By and large, the best pianos seem to have been designed along 
similar lines, with a few notable exceptions.  I would need to hunt for 
quite a while to come up with more than a couple of scales that would agree 
with your practice.

> >As to "blending the tone", by which I understand matching as far as
> >possible the harmonic balance of the adjacent break notes and not merely
> >avoiding the most shocking of breaks, here the actual design and details of
> >manufacture of the strings also plays an important part.  I heard someone
> >say not long ago in front of an audience that a piano needs to be 9'6" long
> >in order to achieve a satisfactory break between steel and covered strings!
>
>Whatever blending the tone means, I've produced pianos in which pianists
>and technicians couldn't find the monochord/bichord, bichord/trichord, or
>bass bridge/tenor bridge transitions without looking. All well under 9'6"
>long, incidentally. It's doable, but you have to give up the old soundboard
>and bridge configuration in favor of one that works.

I thought I made it clear the 9'6" thing was not serious, though clearly 
the man who said it thought it was.  To me it was a joke.  Without changing 
any bridges or anything, a perfectly acceptable break can be achieved on 
any reasonable-sized grand or upright simply through good string scaling, 
which like all piano things involves a good deal of the intuition of 
experience besides the "science", much of which is contradictory and 
devised by acousticians who play the trombone or something.  There are, of 
course, cases where I would love to reshape the long bridge if the job 
would stand it, but if a piano has lasted 100 years sounding good with a 
less than perfectly shaped bridge, I reckon it deserves to carry on for 
another 100 or so without losing its defects of character.  For example, it 
is the high tension in the tenor of a Blüthner and the unusually thin cores 
or the monochords that help to make up the "Blüthner sound".

JD