more bass scaling questions

[Gene Nelson]

At 18:12 -0700 21/7/08, Gene Nelson wrote:


Just a few comments on the specific case.  You don't mention how long
the piano is or other details such as the shape of the long bridge at
the tenor end, the core diameters, and whether note 30 is on the bass
bridge or the long bridge,

< Piano is 5'8", long bridge is relatively straight at lo tenor, notes 26-30 
(bichords)are
on the long bridge,  # 10 core = #22, spl = 1156.5mm,
#11 core = 19.5, spl = 1148mm.  #30 core= #19, spl = 985mm,
Note #31 = #19 and spl = 964.5mm

 A significant change in tension is
indeed necessary at the breaks, but the breaks must be in the right
place to start with.

< This confirms my suspicion that a smooth/uniform unison tension is not 
necessarily
desirable across the breaks?
Cannot change the break locations at this point in the project but for 
future
projects I need to learn more about the process.

As to the pair at note 30, I can say without knowing anything else
that the tension is far to high, probably dangerously so, and
certainly the jump in tension is excessive, militating against a
smooth tonal transition.  The tension on the note 31 triplet is
slightly low but probably the best that could be managed given the
scale.  It is probably not so low as to give serious stability
problems as discussed in another current thread. You would probably
find that making the top pair, note 30, on a 16.5 core to come to
pitch at about 180 lbs would improve the break.

< I will input the #16.5 core into the scale to see how the tension will 
decrease.
I assume that I would also decrease wrap diameter? Current = .057in

Thanks so much for your response.
Gene