Falsetto
The high head voice of the man, falsetto.
What it means
Fistelstimme is a colloquial German designation for falsetto, that is, for the high head voice of the male voice. The vocal folds vibrate differently from the chest voice: more stretched, with less mass and without complete closure, from which a lighter, overtone-poorer, and often somewhat breathy sound arises. The transition to the chest voice lies differently depending on the voice and is audible as a break in untrained singers. The term is often used pejoratively in everyday speech; technically it merely describes a register.
Musical use
As an artistically trained register, falsetto is the basis of the voice type of the countertenor or altus, who thus sings an extensive repertoire from the Renaissance and Baroque as well as newer works. In addition it is used in many traditions of popular and folk music, for instance in yodelling, where the deliberate, audible change between chest and head voice is a stylistic feature. In the classical male voice it also serves as an exercise means to keep the high register free and to smooth the register transition.
Performance practice
Practise the change between the registers in calm lines, descending as well as ascending, and without an increase of volume; the break disappears through evenness, not through force. Keep the larynx relaxed and the breath deeply supported, because pressed falsetto sounds narrow and short of breath. Work on an even vowel colour across the transition. Expect the register to be less sustaining and to demand more care in the handling of the text in large rooms. Warm up the voice thoroughly before you work in this register.
Remember that the register loses carrying power in the low range: where the head voice no longer carries, the change into the chest voice is necessary, and this change has to be practised so that it does not appear as a break. Avoid pressing, because pressed falsetto sounds narrow and tires the voice. For performances in large rooms, intelligibility of the text is to be watched especially. Practise the change into falsetto on vowels such as u or o, because they ease the adjustment.