more bass scaling questions

[Gene Nelson]

> Yes.  A piano of this length ought to have more singles (say 13) and more 
> notes on the bass bridge (say 28 or 29). The problems with this type of 
> scale are as follows:
>
> 1.  Since the bichords go down too low in the scale, it is impossible to 
> keep the tension at a proper level (say 190-210 lbs) and at the same time 
> keep the tone acceptable and allow a clean transition to the singles.  The 
> solution is a fudge -- they try different combinations, all of them 
> unsatisfactory, until they get a result that is as close as they can, and 
> there's the scale.

The bass bichords vary in tension from 166 to 215 lbs, the exceptions being
at the extremes - top bichord is 231 and bottom is 154 lbs - right at the 
breaks.

> I suspect, without having all the lengths, that the best arrangement for 
> this piano would be 14 singles and 15 pairs, all on the bass bridge with 
> no break notes on the long bridge.  Thus you would have note 14 with a 
> 21.5 core and a diameter of 3.49mm giving you about 261 lbs and note 15 
> with a 19.5 core and a diameter of 2.92 giving a tension of about 202 lbs.

Looks like a much nicer break.

> Since you need to stick with only 10 singles, you might get a better break 
> by using a double cover on these if they are at present single covered, 
> for example a 22 core with a 0.65 under-cover and 1.00 top cover would 
> give you 4.18 mm and a tension of about 250 lbs.  That's just a hunch.  If 
> I were with the piano and could listen to the break myself, I'd be able to 
> judge better.  Your note 11 strings are too fat and flabby and your note 
> 10 next door is probably a bit too fat but stiff and tight with it.  You 
> need something not quite as tight and more flexible.

Notes # 1 through #10 are double wrap. Curious - are the wrap numbers
that you give the wrap gauge sizes or wrap wire diameters or overall wire 
diameters?
Must convert mm to in for Pscale and it is not computing - I must be missing 
something.

>>>As to the pair at note 30, I can say without knowing anything else
>>>that the tension is far to high...

Agreed.

> Without knowing the piano and all the lengths, I'd guess you might be 
> better off using a 17.5 core for note 30 with a 0.175 cover, which will 
> result in a diameter of 1.30 mm and a tension of 182.  Perhaps use 17.5 
> for all five long bridge bichords and then go down to 16.5 for note 26 
> keeping the tension about the same

This makes #30 look much better.
Thanks for your detailed information

Gene
>