Spectrum effects of subglottal pressure variation in professional baritone singers.

The audio signal from five professional baritones was analyzed by means of spectrum analysis. Each subject sang syllables [pae] and [pa] from loudest to softest phonation at fundamental frequencies representing 25%, 50%, and 75% of his total range. Ten subglottal pressures, equidistantly spaced between highest and lowest, were selected for analysis along with the corresponding production of the vowels. The levels of the first formant and singer's formant were measured as a function of subglottal pressure. Averaged across subjects, vowels, and F0, a 10-dB increase at 600 Hz was accompanied by a 16-dB increase at 3 kHz.