Timbre (pronounced like: Tamber)

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Timbre (pronounced like Tamber)
Pronounciation of timbre

• 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

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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

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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)

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Musical Intervals

• in music, notes are played together or in quick
  succession
• pairs of notes share a relationship called an
  interval

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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

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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?!
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Consonance and Dissonance

• Consonance is the degree to which two tones
  played together sound good
• Dissonance is the opposite

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Consonance and Disonance

• Consonance seems to decrease with increasing
  complexity of the ratio of the tones

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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)
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Auditory Scene Analysis

• Sounds dont 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?

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Auditory Scene Analysis

• Solving this problem is called Auditory Scene
  Analysis
• One important principle is proximity in pitch,
  time, or spatial location

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Auditory Scene Analysis

• Effect of timing proximity

Slow
Fast
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Auditory Scene Analysis

• Effect of timing proximity

Slow
Fast
Do you hear this?
Pitch
Or this?
Pitch
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Auditory Scene Analysis

• Effect of pitch proximity

close
far
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Auditory Scene Analysis

• Effect of pitch proximity

close
far
Do you hear this?
Pitch
Or this?
Pitch
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Auditory Scene Analysis

• Effect of proximity
• auditory system groups together events that
  happen close together in time and frequency