Steinway upright rebuilding

[Mark Dierauf]

>About twenty years ago (when I knew everything), we were stringing a short
>inexpensive grand, and it had one of those bridges which curves forward at
>the tenor. I figured out the scale, and of course the tension went way down
>in this area. The ScaleMaster (me) knew that we could raise the tension by
>using larger wire, and figured that the horrible tone in this area would then
>be fixed. Well, of course, that also raised the inharmonicity AND the
>output-- the string sounded like welding rod -- really LOUD welding rod.
>Changing to wound wire would have helped, but, depending on the bridge, this
>can also produce two breaks in the tone where there was one.

 And I'm guessing that that temperment wasn't too easy to set, either!

 I don't use the Loudness factor in my program. After talking to Al Sanderson
about it, he convinced me that it was a pretty useless calculation.
 Of course when you increase the core diameter, you will increase inharmonicity
as well. The problem with too short tenor strings is that the tension is too low
AND the inharmonicity is too high, so the inharmonicity gets worse when you go
to a larger wire size.  What you need to do is to increase the one while
decreasing the other, and the ONLY way to do this is to add wrap to the string.
The limiting factor here is the breaking point of the string, which requires the
use of the smaller copper wrap sizes.
 Typically, when you add wrap to a plain tenor, the tension rises to the level
of the adjacent bass bichords, and the inharmonicity drops dramatically.
Increasing the unwrapped ends of these strings will bring the inharmonicity back
into line with both the plain wire above, and the wound strings below (without
altering the tension). If the tenor string are fairly long (as in Mason & Hamlin
or other relatively high tension scales) then you may have to settle for a
little deviation from a perfectly smooth inharmonicity curve at the break
between the new wound strings and the start of the plain wire, but it's
generally still a big improvement from whe jump that existed before at the
bass/tenor break. It's always possible to get the new bass/tenor break right,
though, by using the unwrapped ends as I said.
 In my experience, (and I've done quite a few of these, now), there is little or
no tonal break after the piano is strung - I always get my technician friends to
try to fing the breaks with the lid down, so they can't cheat by looking!
 The other thing that is much improved is the ability to set a good temperment.
On smaller scales I often take the new wound strings right up to F-33 or even
beyond, in other words into the temperment area. All of the tuning tests will
work, you can get good octaves AND good fifths, and you get better tuning
stability to boot.

                  Mark Dierauf