SAT/Inharmonicity Observation

[Kevin E. Ramsey]

    Terry, you remember the discussion we had a week or so ago about the low
tension in the lower tenor on the Yamaha GH1? One of the members came back
with figures that supported my theory of the tenor section tension being
dropped too low, and the inharmonicity factor was about double what it was
in the top note of the bass section.
Therefore, you could safely assume that the inharmonicity would obviously
change  with that great a change in the overall tension of the string.
    On an other note; when a piano is that flat (-140c), the first time
through I will just pull it up to pitch, or maybe a little sharp, and see
what happens when I tune the unisons. I count on two pitch raises. Otherwise
you're pulling individual strings fourty cents sharp for a differential of
180 cents between the tuned and un-tuned notes. Scares me!
   I'm sure that you do things pretty much the same way, let me know. I just
said that more for the newbies who may be lurking.



Kevin E. Ramsey
ramsey@extremezone.com
----- Original Message -----
From: "Farrell" <mfarrel2@tampabay.rr.com>
To: <pianotech@ptg.org>
Sent: Saturday, June 02, 2001 7:32 PM
Subject: SAT/Inharmonicity Observation


> I serviced a 1940 Chickering Studio today. Hadn't been tuned in decades -
> very good condition. It was 140 cents flat. I did an FAC calculation with
> the strings 140 cents flat. FAC values were 10.5, 11.2, and 8.5. Raised
the
> pitch up to A440. Figured maybe I should double check - maybe
inharmonicity
> would change. FAC values @ A440 were 8.7, 9.7, and 7.0. All decreased by
> about 1.5. I would imagine this simply follows some sort of theory, which
> obviously I have no knowledge of. Just thought some might be interested.
> :-)
>
> Terry Farrell
>
>