|Acoustics of the saxophone
Bb tenor saxophone
Notes are the written pitch.
This is the seventh note in the second register. It differs from G#4 (the corresponding note in the first register) in that it uses a register hole. This causes a leak in the bore that weakens and mistunes the first impedance peak, but has little affect on higher peaks – see register hole for an explanation, and compare with G#4, whose impedance spectrum is almost identical except for the first peak. Above about 1 kHz, the third peak is weakened and the rest of the curve is irregular: see the discussion in cut-off frequency.
This is the highest note to use the first register hole (a small hole, but not the one near the mouthpiece), so the register key is not near the node in this fingering, and hence does not weaken the first peak effectively. The saxophone has an automatic octave key.
Compare with the impedance spectrum for a soprano sax on written G#5: same fingering but sounding one octave higher.
This sound spectrum includes transient excitation from the beginning of the note, and so has traces of a subharmonic being excited (compare G#4).
Sound spectrum of a Bb saxophone played using fingering for G#5.
For more explanation, see Introduction to saxophone acoustics.
You can hear G#5 played.