Difficulties in Piano construction

Paul writes:

>is this a reasonable paraphrase of what you are saying?
>(1) The same degree of more or less random detuning that happens with
>time would be more noticable with ET than with an unequal temperament,
>because you can immediately hear when the ET becomes non-equal.
>(2) However, the same degree of detuning does _not_ happen with time;
>measured in cents (or whatever), pianos tuned in ET tend to go farther
>out of tune in the same amount of time than those tuned in unequal
>temperaments (or go out the same distance in less time).


Yes. Why this is so, I don't know, but I have been corresponding with
other techs, and they observe the same thing. Well temperaments seem to be
more stable.
Being able to hear the divergence more readily is not the only answer,
however. The measured amount of "out-of-tuneness" is greater with ET than
with the Well temperaments. This is evidenced in the unisons, which puzzles
me, ( sometimes I am easily puzzled). (have you ever really noticed what a
strange word "puzzle" is?)


> Yes, I have read Fletcher, but it doesn't explain why the >>inharmonicity
of a piano wire measures higher as the tension is >>increased. Perhaps there
is a point of reversal, inre >>tension/inharmonicity.

>This is something I've not heard before, and it sounds very interesting.
>Could you go into greater depth about this?

If I measure the sharpness(relative to a multiple of the fundamental) of
the 5th partial on a piano wire, and then tune it up a whole step and measure
the sharpness again, it will have increased, (more so than the increased Hz of
the fundamental would have made me expect). Also, the piano that is tuned at
A-444 will have a greater increase in the stretch than if it is tuned at
A-440. Once again, this puzzles me, as the theory would indicate otherwise.
Regards,
Ed Foote