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Hi Mark,
Good question.
Sound is a longitudinal wave moving through an elastic medium, e.g.
air. Molecules of air, compressing and expanding inside a flute, move
faster as temperature increases. The pitch or frequency produced by a
shakuhachi is directly proportional to the ambient temperature of a
room or environment in which it is being played. Since, the speed of
sound in air depends on the temperature of the air, a perfectly
pitched shakuhachi at room temperature (68 degrees F or 20 degree C)
will fluctuate with deviations from this standard.
How much?
A flute will go sharper as air warms because the speed of sound in
air increases at the square root of temperature. Going from 60
degrees F to 80 degrees F, temperature increases approximately 4%, so
sound goes 2% faster and the note produced is about one-third higher.
If an instrument's pitch deviates by 2% , it is definitely noticeable.
Here's another way to look at this.
The speed of sound in air at 32 degrees F or 0 degrees C is 331.5 m/s
and increases by 0.6 m/s for each rise of 1 C. Thus, a 331.5 hz.
tone has a wavelength of 1 meter in 0 degree C air. At 33.8 degrees
F or 1 degree C, a 332.1 hz. tone has a 1-meter wavelength. This
difference is hardly discernable, but at 50 degrees F or 10 degrees
C, a 337.5 hz. tone has a 1-meter wavelength and is roughly a third
of a semitone from 331.5 Hz and quite apparent.
In my workshop you will find a very accurate thermometer right next
to the pitch meter located in a small room within the larger
building. Since I heat the shop with wood, in winter I must keep an
ample supply of finely split kindling on hand to get the room
temperature up as close to 68 degree F as possible. The tuning room
is very thoroughly insulated by design to keep it at or below room
temperature precisely for this purpose during the hot summer months.
All the best,
Monty
>I've often wondered about the relationship of pitch and room
>temperature. Obviously, flutes play flat in cold weather and sharp
>in warm weather and there are ways to adjust for this, but at what
>temperature are flutes optimally in tune and to what degree (no pun
>intended) do makers take this into consideration? In other words,
>if it's 55 degrees and my instrument is playing 15 cents flat, is
>that "normal"? Should it play well in tune at 70 degrees and sharp
>at 80 degrees? Has anyone studied this?
>
>Mark Miller
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--></style><title>Re: [Shaku] pitch and temp</title></head><body>
<div><font color="#000000">Hi Mark,</font></div>
<div><font color="#000000"><br></font></div>
<div><font color="#000000">Good question.</font></div>
<div><font color="#000000"><br></font></div>
<div><font color="#000000">Sound is a longitudinal wave moving through
an elastic medium, e.g. air. Molecules of air, compressing and
expanding inside a flute, move faster as temperature increases. The
pitch or frequency produced by a shakuhachi is directly proportional
to the ambient temperature of a room or environment in which it is
being played. Since, the speed of sound in air depends on the
temperature of the air, a perfectly pitched shakuhachi at room
temperature (68 degrees F or 20 degree C) will fluctuate with
deviations from this standard.</font></div>
<div><font color="#000000"><br>
How much?</font><br>
<font color="#000000"></font></div>
<div><font color="#000000">A flute will go sharper as air warms
because the speed of sound in air increases at the square root of
temperature. Going from 60 degrees F to 80 degrees F, temperature
increases approximately 4%, so sound goes 2% faster and the note
produced is about one-third higher. If an instrument's pitch deviates
by 2% , it is definitely noticeable.</font></div>
<div><font color="#000000"><br></font></div>
<div><font color="#000000">Here's another way to look at
this.</font></div>
<div><font color="#000000"><br></font></div>
<div><font color="#000000">The speed of sound in air at 32 degrees F
or 0 degrees C is 331.5 m/s and increases by 0.6 m/s for each
rise of 1 C. Thus, a 331.5 hz. tone has a wavelength of 1 meter
in 0 degree C air. At 33.8 degrees F or 1 degree C, a 332.1 hz.
tone has a 1-meter wavelength. This difference is hardly
discernable, but at 50 degrees F or 10 degrees C, a 337.5 hz. tone has
a 1-meter wavelength and is roughly a third of a semitone from 331.5
Hz and quite apparent.</font></div>
<div><font color="#000000"><br></font></div>
<div><font color="#000000">In my workshop you will find a very
accurate thermometer right next to the pitch meter located in a small
room within the larger building. Since I heat the shop with wood, in
winter I must keep an ample supply of finely split kindling on hand to
get the room temperature up as close to 68 degree F as possible. The
tuning room is very thoroughly insulated by design to keep it at or
below room temperature precisely for this purpose during the hot
summer months.</font></div>
<div><font color="#000000"><br></font></div>
<div><font color="#000000">All the best,<br>
<br>
Monty</font></div>
<div><font size="-2" color="#000000"><br>
</font><br>
</div>
<div><br></div>
<blockquote type="cite" cite>I've often wondered about the
relationship of pitch and room temperature. Obviously, flutes
play flat in cold weather and sharp in warm weather and there are ways
to adjust for this, but at what temperature are flutes optimally in
tune and to what degree (no pun intended) do makers take this into
consideration? In other words, if it's 55 degrees and my
instrument is playing 15 cents flat, is that "normal"?
Should it play well in tune at 70 degrees and sharp at 80 degrees?
Has anyone studied this?<br>
</blockquote>
<blockquote type="cite" cite>Mark Miller</blockquote>
</body>
</html>
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