Acoustics of the clarinet

Bb clarinet


Music Acoustics UNSW

E3 F3 F#3 G3 G#3 A3 A#3 B3
C4 C#4 D4 D#4 E4 F4 F#4 G4 G#4 A4 A#4 B4
C5 C#5 D5 D#5 E5 F5 F#5 G5 G#5 A5 A#5 B5
C6 C#6 D6 D#6 E6 F6 F#6 G6 G#6 A6 A#6 B6
C7 C#7


a key depressed
a key not depressed
a hole covered
a hole uncovered
a part of the mechanism that is not normally touched
Details in fingering legend.

Acoustic schematic
a closed tone hole
an open tone hole

Non-specialist introduction to acoustic impedance
Non-specialist introduction to clarinet acoustics

Notes are the written pitch.
Frequencies are the sounding frequency, for Bb clarinet.
Unless otherwise stated, the impedance spectrum is for a Bb clarinet.

Impedance spectrum of a Bb clarinet measured using fingering for A6.

This is very nearly the same fingering as for E6 (it doesn't have the extra venting with the G#/D# key) and is very similar to that for C4 and G5. The open register holes lower and displace the first two peaks substantially, and that of the third peak less substantially. So of course you have to watch that it doesn't 'fall down' to a pitch near that third peak (near E6). With the first, third and fifth harmonics out of the way, we get something close to the 7th harmonic of C4. This would normally be a very flat minor twenty-first above C4 (two octaves and a flat minor seventh - see the sound spectrum for C4), however the positioning of the register holes and effects of the bore downstream flattens it more or less into tune at a major twentieth (two octaves and a sixth).

In the sound spectra below, note that there is no longer any systematic differences among odd and even harmonics. At low frequencies, the resonances of the clarinet bore support the odd harmonics more, but at frequencies above the cut-off frequency for the clarinet, there are usually no bore resonances (ie peaks in the impedance spectrum) to support harmonics. The reed can produce both odd and even harmonics, and these are radiated by the clarinet, which acts a little like a megaphone at these frequencies.

Sound forte

Sound spectrum of a Bb clarinet played using fingering for A6 forte .
For more explanation, see Introduction to clarinet acoustics

Sound Clip forte

You can hear A6 forte played.

For this note (and also for E3, F3 and G4), we show spectra for different loudness or dynamic level (f, mp and pp). Note that the main distinguishing feature of a loud note is that more high harmonics appear and that the harmonics already present become stronger. The more and stronger harmonics change the timbre of the sound, making it brighter or less mellow: listen to the sound files. They are also very effective at making it louder, because our ears are most sensitive in the range 1-4 kHz. (See What is a decibel?) Note also that the base line for all spectra is a broad band 'noise' containing all frequencies. This is due to the turbulence of air passing through the reed opening, and it is an important part of the characteristic clarinet sound, particularly at the beginning of a note.

For a discussion of how the reed motion produces different timbre and dynamic levels, see Playing softly and loudly.

Sound mezzopiano

Sound spectrum of a Bb clarinet played using fingering for A6 mezzopiano.

Sound Clip mezzopiano

You can hear A6 mezzopiano played on a Bb clarinet.

Sound pianissimo

Sound spectrum of a Bb clarinet played using fingering for A6 pianissimo.
For more explanation, see Introduction to clarinet acoustics

Sound Clip pianissimo

You can hear A6 pianissimo played on a Bb clarinet.

Fingering legend
How were these results obtained?

Contact: Joe Wolfe /
phone 61-2-9385-4954 (UT +10, +11 Oct-Mar)
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