Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!casbah.acns.nwu.edu!ils.nwu.edu!aristotle.ils.nwu.edu!sandell From: sandell@aristotle.ils.nwu.edu (Greg Sandell) Newsgroups: comp.music Subject: Re: Formants (was Re: ,perect pitch) Message-ID: <1368@anaxagoras.ils.nwu.edu> Date: 14 Apr 91 06:32:19 GMT Sender: news@ils.nwu.edu Reply-To: sandell@aristotle.ils.nwu.edu (Greg Sandell) Distribution: world Organization: The Institute for the Learning Sciences Lines: 49 allyn@milton.u.washington.edu writes: > >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. The interesting thing is that in years of experiments spectrum always shows up to be the most prominent dimension, and onset comes in second place. If you look at the semantic terms listeners use to describe timbre, the most frequently used ones pertain more to spectrum (dark, bright, rich, brilliant, mellow, warm, nasal, dull). The ones pertaining to attack (biting, incisive, soft, hard) are less frequent in use. Outside of the laboratory, timbre is apprehended over time, over exposure to a number of notes. Certainly part of the apprehending process is hearing a number of different onsets over several different pitches. The attack's duration, noisiness, presence of inharmonicity changes a bit from one note to the next, but not that much. Not as dramatically as does the spectral envelope from one pitch to the next, which in fact show rather beautiful patterns of change across an instrument's playing range. And spectrum changes in interesting ways according to the force with which the note is played; the changes is onset caused by dynamic are salient, but not as rich in patterned information. Most of the seminal studies that revealed the priority of the attack portion were from around 1963, and were based on isolated notes. We could make more sophisticated experiments now. Here's my question: if you took a clarinet melody of substantial length and melodic span, and replaced all the attacks with trumpet attacks, would anybody think they were hearing a trumpet tune? Roger Kendall has a study (MUSIC PERCEPTION 4/2) where he played clarinet, violin and trumpet melodies in conditions with the attacks excised, just steady states. Listeners could tell what instruments they were hearing. They showed poorer performance in conditions where only the attack portions were presented. Oddly enough, when listeners had to identify instruments from a singly presented note, they did equally well with attack-only and steady-state only. So the priority given to the attack from those old 1963 studies needs to be re-evaluated. Greg Sandell -- Greg Sandell sandell@ils.nwu.edu