Acoustics of baroque, classical and modern flutes

baroque flute


Music Acoustics UNSW

modern B modern C classical C classical D classical flared baroque B3
D4 D#4 and Eb4 E4 F4 F#4 G4 G#4 and Ab4 A4 A#4 and Bb4 B4
C5 C#5 D5 D#5 and Eb5 E5 F5 F#5 G5 G#5 and Ab5 A5 A#5 and Bb5 B5
C6 C#6 D6 D#6 and Eb6 E6 F6 F#6 G6 no G#6 on baroque flute A6


Acoustic and Fingering Schematic
a covered tone hole or key pressed
an uncovered tone hole or key not pressed
a partly covered hole

Details in fingering legend.

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

Impedance spectrum of a baroque flute measured at the embouchure hole using fingering for A4 and A5. Z is plotted in dB, i.e. 20 log(Z/Pa.s.m-3).

This is implicitly a cross fingering (the key leaves the last hole closed), however the four successive open holes make the effect of cross fingering very small for the first two resonances. Notice, however, that the third and subsequent minima are irregular and non harmonic.

The series of open holes acts as a filter to pass high frequencies (the wave doesn't reflect as well for high frequencies, so the instrument doesn't resonate as well). For this flute, the effect occurs not far beyond 1 kHz (it depends on the size of the holes). This effect diminishes the size and regularity of minima (and maxima), and so reduces the power at high frequencies. On the classical flute, the effect appears at around 1.5 kHz, and it is above 2 kHz on the modern flute. This explains the successively brighter timbre of the later instruments. The difference between the lowest note and a note with several holes open is greater on the conical flutes than on the Boehm flute. One might informally say that, because the Boehm flute has more and bigger tone holes, opening up the holes on Boehm flute is closer to 'sawing the end off', whereas the smaller and more widely spaced holes on the conical flutes have a greater effect when they are open downstream.

On the modern flutes, this fingering can be used for the D6-E6 trill, but on the baroque instrument, the third minimum is already in the non-harmonic region.


Sound spectrum of a baroque flute played using fingering for A4.

Sound Clip

You can hear A4 played by Matthew Ridley.

Fingering legend
How were these results obtained?
Acoustic measurements are available for these flutes -
modern B, modern C, classical C, classical D, classical flared, baroque
Sound clips are available for modern B, classical flared and baroque
To compare flutes, it is easiest to open a separate browser window for each instrument.

Copyright © Academic Press. JSV+ Joe Wolfe, John Smith, John Tann and Neville H. Fletcher, Acoustics of baroque, classical and modern flutes
Revised to include the baroque flute 2001.