hearing & deafness (5) timbre, music & speech vocal tract
Post on 21-Dec-2015
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Pitch and Formants1. Harmonics (giving pitch) produced by vocal cord vibration
frequency125 Hz (fundamental)
FormantsF1 = 396HzF2 = 1520Hz
F3 = 1940Hz
2. Formant frequencies: resonances of the vocal tract3. Formant frequencies change as you change the
shape of your vocal tract
What determines an instrument’s timbre
1. “formant” frequencies
2. Amplitude envelope
3. Onset / offset transients
Instrument timbre does not scale - it is more like speech formants
Timbre does NOT stay constant when
sounds are simply scaled up in frequency
frequency ->
dB
Timbre stays more constant when the
formants stay constant
frequency ->
dB
frequency ->
dB
maximum amplitude
maximum amplitude
maximum amplitude
Cheap synthesisers do this to generate different notes
Natural instruments and good synthesisers do this
Forwards & backwards temporal envelopesTrack 54
Track 56
Time (s)0 0.891633
–0.1693
0.1385
0
Time (s)0 0.891633
–0.1693
0.1385
0
Why are some intervals consonant and others dissonant?
Consonant musical intervals form simple ratios
octave 2/1 fifth 3/2fourth 4/3 major third 5/4minor sixth 8/5minor third 6/5major sixth 5/3 major second 9/8
consonant
dissonant
Two complex tones separated by a perfect fifth (3:2)
Separate Excitation Patterns
0.0
5.0
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25.0
30.0
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frequency
One
Two
Total Excitation Pattern
0.0
5.0
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frequency
Consonant intervals havemaximally separated component frequencies