FYIs A Slide Show Cylindrical bore The diameter of register is strong in the odd harmonics only a cylindrical bore remains constant along its length The acoustic behavior depends on whether the instrument is ID: 461276
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Slide1
A
Few Flute
FYIs
: A Slide ShowSlide2
Cylindrical bore
The
diameter of
register, is
strong in the odd harmonics only
.
a cylindrical bore remains constant along its length. The acoustic behavior depends on whether the instrument is
stopped (closed at one end and open at the
other), or
open (at both ends). For an open pipe, the
wavelength produced by the first normal mode (the fundamental note) is approximately twice the length of the pipe. The wavelength produced by the second normal mode is half that, that is, the length of the pipe, so its pitch is an octave higher; thus an open cylindrical bore instrument
overblows
at the octave. This corresponds to the second harmonic, and generally the harmonic spectrum of an open cylindrical bore instrument is strong in both even and odd harmonics. For a stopped pipe, the wavelength produced by the first normal mode is approximately four times the length of the pipe. The wavelength produced by the second normal mode is one third that, i.e. the 4/3 length of the pipe, so its pitch is a twelfth higher; a stopped cylindrical bore instrument
overblows
at the twelfth. This corresponds to the third harmonic; generally the harmonic spectrum of a stopped cylindrical bore instrument, particularly in its bottom Slide3
Instruments having a cylindrical, or mostly cylindrical, bore
Include: Clarinet
(stopped
)
Flute
(Boehm system — open)Slide4
Conical bore
The diameter of a conical bore varies linearly with
distance from
the end of the instrument.
A complete
conical
bore would
begin at zero diameter—the cone's vertex. However
, actual instrument
bores approximate a frustum of a cone.
The wavelength
produced by the first normal mode
is approximately
twice the length of the cone measured from
the vertex
. The wavelength produced by the second normal
mode is
half that, that is, the length of the cone, so its pitch is
an octave
higher. Therefore, a conical bore instrument, like
one with
an open cylindrical bore
,
overblows
at the octave
and generally
has a harmonic spectrum strong in both even
and odd
harmonics
.Slide5
Instruments having a conical, or approximately conical, bore include:
Flute (pre-Boehm)
Oboe
Saxophone
Bassoon
Cornet
Euphonium
Flugelhorn
TubaSlide6
Tone Production
There are four basic variables in tone control:
Air speed
Angle of the airstream
Aperture size
&
Head joint placement