Better Bass Scale for M&H A

[Delwin D Fandrich]

----- Original Message -----
From: "Mike and Jane Spalding" <mjbkspal@execpc.com>
To: <pianotech@ptg.org>
Sent: November 01, 2002 7:57 AM
Subject: Better Bass Scale for M&H A


> List,
>
> I am rewhatevering a M&H A, scale #4, serial number in the 38000's, ca.
1929.  The bass string diameters seem unusual to me.  Several strings will
have the same core AND winding diameter, then both will change, repeat for
several strings, etc.  Tension curve and Inharmonicity curve have the same
sawtooth shape you see in the solid wires, with tension steps of around 20%,
some over 40%.  Warning:  This is the first bass scale I have analysed, and
I'm using, for the first time, my spreadsheet with the "Calculating
Technician" formulae.  So there is a possibility of some error or
misunderstanding on my part (but I'm pretty good with a micrometer, and you
can trust my diameter measurements).  A colleague has a similar vintage A in
his shop, and the bass wire diameters are the same as mine.  Bass strings on
both pianos appear to be original.



>
> So, is this a bad scale, and can/should it be improved?  If yes and yes,
there must be a lot of them out there, and somebody has (or several
somebodies have) already  designed a better scale for this piano.
Reinventing the wheel can be educational and even fun, but not necessarily
profitable.  Can anyone point me towards an existing good rescaling for this
piano.  Note, moving/replacing the bridge to increase back scale length is
not in the program this time around, so the string lengths will not be
changed.


    I'm sure you're reading it correctly--what you're seeing is a
characteristic of this scale. And you're right--it's not a particularly good
scale.

    But simply rescaling the bass of this piano won't help all that much.
You say you want to avoid altering the bridge to increase the backscale but,
of course, this is what the piano really needs. And it can be done with
little effort and time. In most cases the bass bridge assembly can be
removed from the soundboard without too much effort. And, even if you dont
want to make a new bass bridge or recap the original, it does not take all
that much to cut the original bridge body off the cantilever and move it
forward some. Use a shim just the size of the saw kerf and glue the bridge
body back on the cantilever as far forward as possible. (In this M&H the
cantilever is flat.) For the best results you should grind a bit off of the
plate toward the bass end. All told, you should be able to get around 75 to
80 mm of backscale length at A-1. While still not great, it is a
considerable improvement over the original. We've just finished doing a job
like this. It was very successful and it didn't add all that much to the
overall time of the job. (In our case we coupled the relocated bass bridge
with vertical hitches through the mono-chord section.)

If I had to take my choice between rescaling and moving the bass bridge on
this scale, I'd move the bridge every time. No matter what waveforms you
have in the strings, if you tie the soundboard down and don't let it move
you won't get much sound out of the piano.

Del