baroque flute

A5

Impedance

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

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.