[Whistler for two voices (sound of whistle produced by man) (author's transl)].

"Double tone whistling" is the rare ability to produce two different tones of whistle with the mouth at the same time and with volitional intervalls between two tones: melodies being whistled this way sound therefore as two voices. With two persons who have this ability we could tape several melodies, analyse them and conclude from this the origin of the two single tones. Beside that we also could analyse a case of "tripletone" melodies and compare it with the results of our sonogramms. The recordings were analysed with the AF-spectrum-analyser Songraph 6061 B. From the interpretation of the patterns follows: In nearly all cases there is a "switching over" between two tones (see Figs. 1, 4, 5). The intervall between the two tones is not fixed but harmonic. Listening to this gives the impression of tremolo. One of our persons could even continue whistling are tone after the change over to the other tone for a short time (about 50 msec). You get the impression of "switching over" even when only listening to the recording of the double-tone whistling of person 2. As mentioned above, we were able to analyse the "melodies for three voices" as indicated by Scheminzky (1957). "Double tone whistling" and independent humming at a lower frequency form this three voices of the "three voice melody". In opposition to Scheminzky's conjecture, a changing over and not a continuous side by side of the two single tones is the basis of this "doubletone whistling". The results of our analysis are: Person 1 seems to be able to form two resonant rooms in the mouth cavity with the tongue with two resonance frequencies. Person 2 could indicate two kinds of whistle at two voices: a) The tongue is being moved forth and back in the rhythm of the switching over. b) The tongue is being fixed and the cheeks change the shape of the mouth-cavity in the rhythm of the change over.