Timbre (pronounced like: Tamber) • pure tones are very rare • a single note on a musical instrument is a superposition (i.e. several things one on top of the other) of many related frequencies called harmonics Pronounciation of “timbre”
Timbre • the characteristic of a particular set of harmonics is called timbre • e.g. the set of harmonics generated when a particular key is pressed on a piano • timbre is why we can tell the difference between the same notes played on difference instruments
Timbre • Although any musical “note” is a superposition of harmonics, you still hear it as a single pitch (you hear its tone height) • The pitch that you hear is (usually) the fundamental frequency (except in the artificial case of the “missing fundamental”)
Musical Intervals • in music, notes are played together or in quick succession • pairs of notes share a relationship called an interval
Musical Intervals • Within each pair, the higher pitch (f2) is some multiple of the lower pitch (f1): • e.g. 200 hz and 400 hz -- f2 is two times f1
Musical Intervals • f1= 400 f2 = 800 • (f2 = 2 x f1)…octave • f1= 400 f2 = 600 • (f2 = 3/2 x f1)…perfect 5th • f1= 500 f2 = 800 • (f2 = 8/5 x f1)…minor 6th • f1= 400 f2 = 550 • (f2 = 11/8 x f1) octave perfect 5th minor 6th not quite a perfect fourth?!
Consonance and Dissonance • Consonance is the degree to which two tones played together sound “good” • Dissonance is the opposite
Consonance and Disonance • Consonance seems to decrease with increasing complexity of the ratio of the tones
Music is combinations of intervals played in series (with some rhythm) • Combination of three different intervals is a chord (major or minor) • Additional intervals modify the sound of the chord major minor 4 notes/6 intervals (major 7) 3 notes/3 intervals 4 notes/6 intervals (dominant 7)
Auditory Scene Analysis • Sounds don’t happen in isolation, they happen in streams of changing frequencies • How does the system group related auditory events into streams and keep different streams separate?
Auditory Scene Analysis • Solving this problem is called Auditory Scene Analysis • One important principle is proximity –in pitch, time, or spatial location
Auditory Scene Analysis • Effect of timing proximity: Slow Fast
Auditory Scene Analysis • Effect of timing proximity: Slow Fast Do you hear this? Pitch Or this? Pitch
Auditory Scene Analysis • Effect of pitch proximity: far close
Auditory Scene Analysis • Effect of pitch proximity: far close Do you hear this? Pitch Or this? Pitch
Auditory Scene Analysis • Effect of proximity: • auditory system groups together events that happen close together in time and frequency