Hearing & Deafness (5)

Hearing & Deafness (5)

Timbre, Music & Speech

Vocal Tract

Source & Filter

Larynx Vocal tract Output sound

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

Vowel production

Tuvan throat music

Tuvan throat music - 2

Vocal tract change

Me (m)

Higher pitch Shorter vocal-tract(higher formants)

Both (-> f)

narrow-band spectrogram

sine-wave speech

SWS

Adding harmonics to make an instrument’s timbre

Track 53

Different notes on clarinet and oboe

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

Bassoon & violin notes

Track 57

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

Onset transients

Time (s)0 0.0842

ﾐ 0.6922

0.7817

0

Time (s)0 0.0842

ﾐ 0.6922

0.7817

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

10.0

15.0

20.0

25.0

30.0

0 500 1000 1500 2000 2500 3000frequency

One

Two

Total Excitation Pattern

0.0

5.0

10.0

15.0

20.0

25.0

0 500 1000 1500 2000 2500 3000frequency

Consonant intervals havemaximally separated component frequencies