Basic acoustics

NCTU Yuwen Laihttp://gph.is/1uCKerE

http://gph.is/1uCKerE

Series of rapidly expanding concentric spheres of alternate compression and rarefaction radiation from the source

Speed of sound: 345 m/s

Sound waves

video

http://emusictips.com/wp-content/uploads/2009/03/sound_waves_animated.gif

Prerequisites for audible sound

Vibration source Propagating medium Frequency and Amplitude in audible range &

Age-related hearing loss

age test

http://www.freemosquitoringtones.org/http://www.freemosquitoringtones.org/

http://www.eldercareresourcesgeorgia.com/wp-content/uploads/2015/05/What-Makes-Hearing-on-the-Telephone-So-Difficult.jpg

.wav .aiff , .mp3 .wmv .ogg

http://s.hswstatic.com/gif/mp3-waves.gif

Vinyl records

http://theawesomer.com/photos/2011/09/092811_alejandro_de_antonio_vi

nyl_portraits_3.jpg

warmer and more detailed sound

http://theawesomer.com/photos/2011/09/092811_alejandro_de_antonio_vinyl_portraits_3.jpg

http://gph.is/1UUEdTx

http://gph.is/1UUEdTx

PhonationPeriodic interruption by vocal folds

air passing through glottis chopped off by vocal folds - creates puffs of air

VFs fundamental frequency (F0)

9

Period and Frequency

Period (T) | the time of one wave period (cycle) in seconds

Frequency (f) Hertz (Hz ), "cycles per second" (cps)

f = ____1T

100 Hz

200 Hz

400 Hz

800 Hz

0.01 sec/10 ms

waveformoscillogram

https://www.youtube.com/watch?v=qx8hrhBZJ98

a fundamental pitch andsimultaneouslyone or more pitches over that.[2]

Throat singing

We mostly dont care about the complex waveform itself, but more on the frequency and amplitude of the simple waves that its made of.

sine wave

We mostly dont care about the complex waveform itself, but more on the frequency and amplitude of the simple waves that its made of.

sine wave

What is a spectrum?

spectrum :

What is a spectrum?

spectrum :

spectrum

x y

spectrum

Source-filter theory

larynx

larynx

F0 , 1st harmonic:

larynx

F0

F0 , 1st harmonic:

larynx

F0

2F0

F0 , 1st harmonic:

larynx

F0

2F0

F0 , 1st harmonic:

2F0 overtones

larynx

F0

2F0

3F0

F0 , 1st harmonic:

2F0 overtones

larynx

F0

2F0

3F0

4F0

F0 , 1st harmonic:

2F0 overtones

larynx

F0

2F0

3F0

4F0

5F0

F0 , 1st harmonic:

2F0 overtones

harmonics harmonics

http://www.phon.ucl.ac.uk/courses/plin/plin2108/images/source-filter.png

http://www.phon.ucl.ac.uk/courses/plin/plin2108/images/source-filter.png

Formant harmonics

Formant harmonics

1st formant

2nd formant

F1

F2

F1, F2 (composition)

Spectrogram x y

Amplitude

bel

decibels (dB)

Phase

Acoustic of consonants

Stops and aspiration

double burst

Voiceless fricatives

turbulent airstream creates a chaotic mix of random frequencies, sounds like static noise

4000 Hz and above

2500 Hz

Voiced fricatives

voice bar

// & /d/, which is which?

A B

Approximants

Link

http://www.youtube.com/watch?v=lPQ6VQzuyxUhttp://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4http://www.youtube.com/watch?v=ztDdFra_Yy4

Nasal

Oral cavity- complete occlusion stable nasal tract formant

Nasal cavity- side branch resonator greatly damped formant from open oral tract

Nasal formants: 250, 2500, and 3250 Hz

Spectrogram readingattack

spectrogram reading

A:the initial schwa B: the closure of the [t] (silence) C: the release burst of the [t] D: the aspiration E: the [] F: the medial phase of the [k] (again, silence) G: the release burst of the [k]

...the absolute values of the formant frequencies are not crucial, but their

relationships are, reflecting the inherent systemic character of phonological

contrast and its encoding in the acoustic speech signal.

Vowel chart

Auditory quality

Articulatory specifications

Phoneticians are thinking in terms of acoustic fact and using physiological fantasy to express the idea(Russell,

1928)

voiced stopvoicing during closure

voice bar 43

voiceless unaspirated [t]

voiceless aspirated [th]

short lag

long lag

44

voiceless unaspirated [t]

voiceless aspirated [th]

short lag

long lag

44

voiced [d]

voiceless unaspirated [t]

voiceless aspirated [th]

45

voiced [d]

voiceless unaspirated [t]

voiceless aspirated [th]

45

voiced [d]

voiceless unaspirated [t]

voiceless aspirated [th]

voice lead

short lag

long lag

45

voiced [d]

voiceless unaspirated [t]

voiceless aspirated [th]

Shindi

p. 147 46

voiced [d]

voiceless unaspirated [t]

voiceless aspirated [th]

Shindi

p. 147 46

voiced [d]

voiceless unaspirated [t]

voiceless aspirated [th]

Shindi

p. 147 46

voiced [d]

voiceless unaspirated [t]

voiceless aspirated [th]

Shindi

p. 147 46

This language has a x-way voicing contrast.

x=2

Mandarin: voiceless aspirated &

x=3

x=4

Cx4

47

voiced(voice lead)

voiceless unaspirated(short lag)

voiceless aspirated(long lag)

48

voiced(voice lead)

voiceless unaspirated(short lag)

voiceless aspirated(long lag)

48

voiced(voice lead)

voiceless unaspirated(short lag)

voiceless aspirated(long lag)

48

voiced(voice lead)

voiceless unaspirated(short lag)

voiceless aspirated(long lag)

48

voiced(voice lead)

voiceless unaspirated(short lag)

voiceless aspirated(long lag)

48

()

49

()

[a25] [ka25] [kha55]

49

()

[a25] [ka25] [kha55]

49

voiced(voice lead)

voiceless unaspirated(short lag)

voiceless aspirated(long lag)

Acquired perceptual bias

50

51

t tf l i s s t n

F0 pitch

Psychoacoustics: the perception of sound

Pitch is a subjective psychoacoustical attribute of sound, not a purely objective physical property

52

F0: pitch:

http://en.wikipedia.org/wiki/Psychoacousticshttp://en.wikipedia.org/wiki/Sound

F0 Pitch

semitone. for music

perceptual scales. judged by listeners to be equal in distancefrom one another. linear at low freq. logarithmic at highfrequency end

mel scale. melody (Stevens, Volkman and Newman, 1937)

http://en.wikipedia.org/wiki/Stanley_Smith_Stevenshttp://en.wikipedia.org/wiki/John_Volkmanhttp://en.wikipedia.org/wiki/Edwin_Newman