Directivity measurement of a singer
Malte Kob, Harald Jers · The Journal of the Acoustical Society of America · 1999
The convenient method of using broadband excitation for fast and accurate evaluation of narrow-band directivity cannot be applied to the human vocal tract. If the voice itself is used as the excitation, the variable properties of the vocal tract change with each differently pronounced phoneme, and therefore a vowel does not yield the same directivity as a consonant. Additionally, the nonstationary character of the voice does not allow for simple measurements with one scanning microphone. In the method described here, the singer stands on a turntable and sings a glissandolike vowel through at least one octave. The sound-pressure level is recorded with two microphones, one as a reference attached to the singer’s nose and the other at a 2-m distance. The spectra of both signals are calculated with a sufficiently long FFT, and the levels are subtracted. For each position of the turntable and every angle of elevation, the spectra are stored on disk and postprocessed within a matlab environment. Measured directivity plots of several human singers are compared with those of an artificial singer that has been built to reproduce the singing voice accurately.