Spectral Analysis - PowerPoint PPT Presentation

1 / 20
About This Presentation
Title:

Spectral Analysis

Description:

This voice quality requires greater medial compression of the vocal folds. ... And therefore the high frequency harmonics have less power, ... – PowerPoint PPT presentation

Number of Views:146
Avg rating:3.0/5.0
Slides: 21
Provided by: Stephen950
Category:

less

Transcript and Presenter's Notes

Title: Spectral Analysis


1
Spectral Analysis
February 14, 2012
2
Friendly Reminders
  • ToBI homeworks to hand back.
  • Extra credit ToBI Production exercise will be
    posted later today.
  • due after the break
  • Mid-term is on Thursday!
  • On the Tuesday after the break, well be back in
    the Craigie Hall lab.
  • Korean stops exercise
  • Todays goal start to learn where spectrograms
    come from.
  • http//sakurakoshimizu.blogspot.com/

3
Voice Quality Summary
AT LT MC Flow Modal moderate varies moderat
e med. Tense high varies high high Creaky high
low high low Whisper low N/A high med. Brea
thy low varies low high Falsetto high high hi
gh low
4
  • Last but not least, Korean makes an interesting
    distinction between emphatic (or fortis)
    obstruents and unaspirated and aspirated (lenis)
    obstruents.

5
Whats going on here?
  • A variety of things occur during the articulation
    of fortis consonants in Korean.
  • Glottis is not open as wide (during closure) as
    in lenis stops.
  • Voicing begins more quickly after stop release
  • Increased airflow in fortis stops.
  • Higher F0 after stop release.
  • Vocal folds are more tense than in lenis stops.
  • greater medial compression
  • squarer glottal waveform

6
Back to the Source
  • Modal voicing (by me)
  • Note completely closed and completely open
    phases are both actually quite short.
  • Also closure slope is greater than opening
    slope.
  • Q Why might there be differences in slope?

7
A Different Kind of Voicing
  • The basic voice quality in khoomei is called
    xorekteer.
  • Notice any differences in the EGG waveforms?
  • This voice quality requires greater medial
    compression of the vocal folds.
  • ...and also greater airflow

8
Why Should You Care?
  • Remember that the most basic kind of sound wave
    is a sinewave.

pressure
time
  • Sinewaves can be defined by three basic
    properties
  • Frequency, (peak) amplitude, phase

9
Complex Waves
  • It is possible to combine more than one sinewave
    together into a complex wave.
  • At any given time, each wave will have some
    amplitude value.
  • A1(t1) Amplitude value of sinewave 1 at time
    1
  • A2(t1) Amplitude value of sinewave 2 at time
    1
  • The amplitude value of the complex wave is the
    sum of these values.
  • Ac(t1) A1 (t1) A2 (t1)
  • Note a harmonic is simply a component sinewave
    of a complex wave.

10
Complex Wave Example
  • Take waveform 1
  • high amplitude
  • low frequency

  • Add waveform 2
  • low amplitude
  • high frequency

  • The sum is this complex waveform

11
Another Perspective
  • Sinewaves can also be represented by their power
    spectra.
  • Frequency on the x-axis
  • Intensity on the y-axis (related to peak
    amplitude)
  • Waveform Power Spectrum

12
Putting the two together
Waveform Power Spectrum




harmonics
13
More Combinations



  • What happens if we keep adding more and more
    high frequency components to the sum?

14
A Spectral Comparison
Waveform Power Spectrum
15
Whats the Point?
  • Remember our EGG waveforms for the different
    kinds of voice qualities
  • The glottal waveform for tense voice resembles a
    square wave.
  • ? lots of high frequency components (harmonics)

16
Whats the point, part 2
  • A modal voicing EGG looks like
  • It is less square and therefore has less high
    frequency components.
  • Although it is far from sinusoidal...

17
Whats the point, part 3
  • Breathy and falsetto voice are more
    sinusoidal...
  • And therefore the high frequency harmonics have
    less power, compared to the fundamental frequency.

18
Lets Check em out
  • Head over to Praat and check out the power
    spectra of
  • a sinewave
  • a square wave
  • a sawtooth wave
  • tense voice
  • modal voice
  • creaky voice
  • breathy voice

19
Spectral Tilt
  • Spectral tilt drop-off in intensity of higher
    harmonics, compared to the intensity of the
    fundamental.

20
The Source
  • The complex wave emitted from the glottis during
    voicing
  • The source of all voiced speech sounds.
  • In speech (particularly in vowels), humans can
    shape this spectrum to make distinctive sounds.
  • Some harmonics may be emphasized...
  • Others may be diminished (damped)
  • Different spectral shapes may be formed by
    particular articulatory configurations.
  • ...but the process of spectral shaping requires
    the raw stuff of the source to work with.
Write a Comment
User Comments (0)
About PowerShow.com