Accu-tip and question

[Roger Jolly]

Hi Newton,
                  I like your Alien space ray jibe, that's what has puzzled
me also. However I have now had several conversations with a Pr of that is
an expert in non linear materials. The equation for Youngs modules is a
linear equation. If we were to look at various limits to add to the formula
a very different picture would emerge. Some variables that we ignore in a
simplistic look, is, diameter due to the elastic stretching of the string,
necking, due to pressure points, bridge pins and pressure bars, this causes
deformities.  We treat music wire with a given set of constants, but unless
we are sure of the exact composition, (nickle etc) the constants are not
absolute.

The two state of the art ET's, I think, give a more accurate picture of
inharmonicity, because they measure the 2nd partial and calculate from a
reference point, the results are tending to prove that the calculated
figure is off.

To do some meaningful experiments with regard to the behavior of music
wire, we are trying to devise a system of test out side of the piano, so as
to take the board out of the loop. Divide and conquer principal.

The changes in the inharmonicity re humidity, has to do with the elasticity
of the hammer, however I have noted changes in partial sustain time with
humidity changes that I think can be attributed to the board bridge system.

Bright pianos definitely exibit the problem most clearly. they are the
hardest to tune due to this inharmonicity problem and the reduction in
harmonic spectrum. they are unforgiving with regards to unisons, and one
more readily hears any tuning drift.

Again lots of questions that are provoking, few provable answers.

Seems to be a subject with few participants.

Regards Roger


At 09:53 AM 13/01/99 -0500, you wrote:
>I'm wondering what could change the math used to calculate
>inharmonicity.  Alien space rays?
>
>I originally posted this observation, that FAC values, especially the A,
>change with the humidity changes from 15% to 85% on the same piano in
>the same room.  At a university tuners tune the same piano time after
>time after time and some things become obvious in that setting that do
>not otherwise.
>
>Water content changes the speed of sound in the wood or the change of
>crown or bearing or change of alien rays.
>
>When the A changes from 6 to a 9 it is hard to account for such without
>alien rays.
>
>                        Newton
> 
Roger Jolly
Baldwin Yamaha Piano Centre
Saskatoon and Regina
Saskatchewan, Canada.
306-665-0213
Fax 652-0505