Klarinet Archive - Posting 000460.txt from 1998/09

From: "Mark Charette" <charette@-----.org>
Subj: Re: [kl] Re: Pitch standards
Date: Tue, 15 Sep 1998 01:28:54 -0400

>Is a=440 at 72 degrees the same as a=440 at 80 degrees?

Yes, it is. 440 cycles per second is an absolute measurement (assuming
we can define a cycle and a second, and neither of those is temperature
dependent).

> Because I read
>in Woodwind quarterly that the london conference established it not
>ioonly by vibration and teperature but location. It said it was 440
>vibrations at a temperture of 72 degrres in a room in london. SO then
>if its 72 degrees in the hall in my school will 440 vibrations be the
>same as this room in london.

No - the _device_ creating the sound may have had to be at a precise
temperature for someone to use it as a referant. That's all. Remember
the separation of the standard vs. the physical construct used for
reference purposes.

It really isn't all that confusing. The definition of concert A
according to the ISO is 440 cycles per second, not relative to anything
other than cycles and time. The orchestras which tune to something other
than 440 do not tune to the precise definition of concert A - they are
some cents sharp or flat to the reference. That's it. All the rest (in
tune with itself, etc.) is really meaningless in the "physics" part (and
those 12th roots, even tempering, are only one kind of tuning).

A tuning fork designed for A=440 may only be accurate at a certain
temperature; in all other cases it can not be used as an absolute
reference. In laboratories there will be a temperature correction chart
which specifies the correction that must be applied to compensate for
the temperature. There could be other factors which cause you to
misinterpret the frequency (don't move relative to the device creating
the vibrations while you're measuring!) - but we'll leave those alone
... for now.

Now, back to practicing this piece whose timing is giving me fits ...
----
Mark Charette@-----.org
Webmaster, http://www.sneezy.org/clarinet
"There can be no freedom without discipline." - Nadia Boulanger

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