Klarinet Archive - Posting 000134.txt from 2009/09

From: "Peter Gentry" <peter.gentry@-----.uk>
Subj: RE: [kl] Antique clarinet length determines diapason?
Date: Mon, 28 Sep 2009 12:04:09 -0400

Diego

Just so all these different meanings and translations. Your diapason is our
tuning fork.

I should have referred to the fundamental frequency of the lowest note - a
definition which should translate without ambiguity.

That is produced with all tone holes covered. This naturally includes a host
of harmonics and other frequencies specific to the instrument the mouthpiece
the reed the performer the air pressure and temperature and the acoustics of
the performance space. This frequency can be altered somewhat by the
performer and cannot be absolute to the instrument it will have a range.

It is for all these reasons that I find the term diapason (in English
anyway) somewhat precious. For a family such as the clarinet key or pitch is
fairly adequate. If an instrument seller does not know which clarinet is
which he should not be in business. Knowledge that a particular example
tends to be sharp or flat may be less widespread.

I sometimes think we should all have spectrographs......:)

regards
Peter Gentry

-----Original Message-----
From: Diego Casadei [mailto:casadei.diego@-----.com]
Sent: 28 September 2009 02:39
To: klarinet@-----.org
Subject: Re: [kl] Antique clarinet length determines diapason?

Dear all,

in Italy (and might be also in other European countries) we call
"diapason" the fork-like tool that gives the central A pitch. You can
find a photo of it in the Italian wikipedia:
http://it.wikipedia.org/wiki/Diapason (which also says that ancient
Greeks were using such term to mean "octave"). On the same page, you
can also find some historical overview of the concert pitches used in
different epochs and places (it's a table: you don't need to master
Italian). For me (I'm Italian) it makes perfectly sense to call
"diapason" the absolute tuning of an instrument, by conceptual extension
from the tool above.

Apart from this linguistic note, I should repeat that a single length
measurement is not sufficient to find the pitch of a clarinet. For
example, the mouthpiece has some effect (Vandoren is selling different
mouthpieces for different tunings), so that it cannot be neglected.

The only reasonable way to find the absolute tuning is to assume that it
existed at least one mouthpiece giving perfect intonation to the
instrument (which is a _strong_ assumption: it's hard to find a modern
clarinet which is perfectly tuned on the full range). This makes it
possible to make repeated measurements over several intervals, as I said
in my first message. Later, one can average over all measurements and
guess where the fixed node was.

The fixed node is the starting point for all measurements, not the
barrel, not the bell. Starting from the fixed node, one can measure the
(quarter of) wavelength that corresponds to any pitch. But forget about
reaching a precision better than few Hertzs :-)

Cheers,
Diego

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