Acoustics of the saxophone

Bb soprano saxophone


Music Acoustics UNSW


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 saxophone acoustics

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

Impedance spectrum of a Bb soprano saxophone measured using fingering for D4.

At frequencies below about 1 kHz, this curve looks rather like that for A#3, B3, C4 or C#4, but raised in frequency because the tube is effectively shorter because of the three open tone holes (see tone holes). At higher frequencies, however, the waves propagate past the open tone holes with greater ease, and the situation is more complicated. See the discussion in cut-off frequency. However, the 1 kHz cutoff means that there are only three strong peaks, so only three notes that one can 'bugle' with this fingering. The first peak can be reduced in magnitude and shifted in frequency using a register hole (operated by the octave key). See D5.

This note is, acoustically at least, a cross fingering: there is a key closed below the first open key, as the schematic inset shows. Because of the large size of the tone holes, cross fingerings have little effect at low frequency.

For general comments about the first register, see A#3. Compare with the impedance spectrum for a tenor sax on written D4: same fingering but sounding one octave lower.


Sound spectrum of a Bb soprano saxophone played using fingering for D4.
For more explanation, see Introduction to saxophone acoustics.

In the sound spectra for the low notes, we can notice a sudden increase in the negative slope of the spectral envelope that occurs close to the cut-off frequency of about 1.2 KHz.

For general comments about the sound spectra of the first register, see A#3, which is the first note of that register.

Sound Clip

You can hear D4 played.

Fingering legend
How were these results obtained?

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