Contributions Of The Piriform Fossa Of Female Speakers To Vowel Spectra

The sound is generated by sound waves oscillation in the vocal tract.The piriform fossa is a paired side branch of the vocal tract and produces anti-resonance(s)in the transfer function.This effect has been known for male vocal tracts,but female data were few.Using the magnetic resonance imaging data,this study investigates contributions of the piriform fossa to vowel spectra in female vocal tracts by means of 3D vocal-tract models and acoustic experiment with the water-filling method.Results from one male and three female subjects indicate that: The piriform fossa of our three female subjects exhibited acoustic effects in the frequency region higher than the male's.The female piriform fossa generates dips in the frequency region of 4-6 kHz and peaks at 6-8 kHz in the vowel spectra.The spectra for filling each cavity separately were observed to vary greatly between subjects and vowels,which indicates the interaction between the left and right cavities.The common summary of the spectral changes is that,when one side is filled with water,there generate two anti-resonances(a smaller dip in the lower frequency and a larger dip in the higher frequency)in vowel spectra.