Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!sdd.hp.com!spool.mu.edu!uwm.edu!ogicse!milton!allyn From: allyn@milton.u.washington.edu (Allyn Weaks) Newsgroups: comp.music Subject: Formants (was Re: ,perect pitch) Summary: vowels are determined by formants, not pitch overtones Message-ID: <1991Apr13.235927.5503@milton.u.washington.edu> Date: 13 Apr 91 23:59:27 GMT Article-I.D.: milton.1991Apr13.235927.5503 References: <425389987@1991Apr7.100059.1489@urz.unibas.> <1094700003@cdp> <1991Apr11.142237.1501@urz.unibas.ch> Organization: University of Washington, Seattle Lines: 33 gaspar@urz.unibas.ch writes: >There is in fact a relationship between vowels and overtones. If you sing >the vowel A and the vowel E at the same pitch it's the overtones that are >forming the different sound of the vowels. Nope. Vowels are recognizable because of formant frequencies caused by the shape of the mouth and vocal tract, and are largely independent of pitch. The formant spectrum is basically an envelope that encloses the pitch spectrum. Pitch is determined primarily by tension in the vocal chords. You can test it yourself by singing 'ah' (or any other vowel) at various pitches. The pitch overtones (and timbre) go with the pitch, but the 'ah' sound stays largely the same - the formant frequency (and _it's_ overtones, which aren't simple harmonics) stay the same for a given vowel. The 'ah' as in father has strong peaks at about 700, 1100, and 2600 Hz. 'oo' as in pool has its strongest peaks at about 300, 700, and 2500 Hz. All of this is somewhat oversimplified of course. I suggest looking up Arthur Benade's _Fundamentals of Musical Acoustics_ for more details. This is the reason that sampled voice sounds on a keyboard are so unsatisfactory - they only sound like a voice at the pitch they were sampled at and if you get more than a whole tone away it all goes to hell, since the sampler is shifting the formant envelope frequencies as well as the pitch. >That is also the way you distinguish different instruments, by the overtones. Only partly. Much more important is the attack - the wild ravings of the first several milliseconds of a note. If you hear only a sustained tone, it's often hard to tell a violin from a flute from a horn. Pianos are more distinctive because of non-linearities in the overtones. Allyn Weaks allyn@milton.u.washington.edu