1. The Speech Chain (Denes & Pinson, 1993)
Tasko SPPA 6010 Advanced Speech Science

2. What information is embedded within the speech acoustic signal?
Phonetic information
Affective information
Personal information
Transmittal information
Diagnostic Information
Tasko SPPA 6010 Advanced Speech Science

3. Branches of science employed to understand speech communication
Physics
Acoustics
Aerodynamics
Kinematics
Dynamics
Biology
Anatomy
Gross anatomy
Microscopic anatomy
Molecular biology
Neuroimaging
Physiology
Electrophysiology
Tasko SPPA 6010 Advanced Speech Science

4. Tasko SPPA 6010 Advanced Speech Science
Physical Quantities
Basic vs. Derived
Scalar vs. Vector
Area
Volume
Displacement
Velocity
Acceleration
Force
Pressure
Work
Power
Intensity
Resistance
Ohm’s Law (V=IR)
Tasko SPPA 6010 Advanced Speech Science

5. Speech anatomy as “tubes” and “valves”
Speech production is achieved through the systematic regulation of air pressures and flows within the lungs and vocal tract.
Tasko SPPA 6010 Advanced Speech Science

6. Source-Filter Theory of Speech Production
The sounds we hear as speech is the product of a sound source that has undergone filtering by the vocal tract
source and the filter may be considered to be independent of each other
Tasko SPPA 6010 Advanced Speech Science

7. Tasko SPPA 6010 Advanced Speech Science
Source-Filter Theory
Tasko SPPA 6010 Advanced Speech Science

8. Tasko SPPA 6010 Advanced Speech Science
Source-Filter Theory
Tasko SPPA 6010 Advanced Speech Science

9. Sound: Acoustics review
What is sound?
Graphic representation of sound
Classifying sounds
Filters
Resonance
The decibel
Tasko SPPA 6010 Advanced Speech Science

10. Tasko SPPA 6010 Advanced Speech Science
What is sound?
It may be defined as the propagation of a pressure wave in space and time.
propagates through a medium
We are going to need to talk more about the medium through which sound propagates. This will seem a little bit like a digression, but it should vastly improve your grasp of the material that we go into later. So we need to talk some physics and physical quantities.
Tasko SPPA 6010 Advanced Speech Science

11. Tasko SPPA 6010 Advanced Speech Science
What is sound?
Mass-spring model
Tasko SPPA 6010 Advanced Speech Science

12. Wave action of molecular motion
Time 1 2 3 4 5
Distance
Tasko SPPA 6010 Advanced Speech Science

13. Tasko SPPA 6010 Advanced Speech Science
Amplitude waveform
Position
Time
Tasko SPPA 6010 Advanced Speech Science

14. Tasko SPPA 6010 Advanced Speech Science
Amplitude waveform
Question: How long will this last?
Amplitude
Time
Tasko SPPA 6010 Advanced Speech Science

15. Model of air molecule vibration
Time 1 2 3 4 5
Distance a b c d
Tasko SPPA 6010 Advanced Speech Science

16. Simple Harmonic Motion: Sine Wave
Features
Amplitude
Period
Frequency Hz
octave
Phase
Pressure
Time
Tasko SPPA 6010 Advanced Speech Science

17. Graphic representation of sound
Time domain
Called a waveform
Amplitude v. time
Frequency domain
Called a spectrum
Amplitude spectrum
amplitude vs. frequency
Phase spectrum
phase vs. frequency
May be measured using a variety of “window” sizes
Spectrogram
frequency v. amplitude v. time
Tasko SPPA 6010 Advanced Speech Science

18. Same sound, different graphs
Time domain
Frequency domain
Tasko SPPA 6010 Advanced Speech Science
From Hillenbrand

19. Are all sound waves simply sinusoids?
NO!
Waves can be summed
Simple waves can combine to produce complex waves
Fourier: French Mathematician:
Any complex waveform may be formed by summing sinusoids of various frequency, amplitude and phase
Fourier Analysis
Provides a unique (only one) solution for a given sound signal
Is reflected in the amplitude and phase spectrum of the signal
Reveals the building blocks of complex waves, which are sinusoids
Tasko SPPA 6010 Advanced Speech Science

20. Classification of sounds
Number of frequency components
Simple
Complex
Relationship of frequency components
Periodic
Aperiodic
Duration
Continuous
Transient
Tasko SPPA 6010 Advanced Speech Science

21. Complex periodic sounds: Graphic appearance
Tasko SPPA 6010 Advanced Speech Science
From Hillenbrand

22. Complex periodic sounds: Graphic appearance
Tasko SPPA 6010 Advanced Speech Science

23. Tasko SPPA 6010 Advanced Speech Science
Brief Digression
Tasko SPPA 6010 Advanced Speech Science

24. Amplitude vs. Phase Spectrum
Amplitude spectrum:
different
Phase spectrum:
same
Tasko SPPA 6010 Advanced Speech Science

25. Amplitude vs. Phase Spectrum
Amplitude spectrum:
same
Phase spectrum:
different
Tasko SPPA 6010 Advanced Speech Science

26. Tasko SPPA 6010 Advanced Speech Science
Digression concluded
Tasko SPPA 6010 Advanced Speech Science

27. Aperiodic sounds: Graphic appearance
Tasko SPPA 6010 Advanced Speech Science
From Hillenbrand

28. What “class” of sound is speech?
Tasko SPPA 6010 Advanced Speech Science

29. The “envelope” of a sound wave
Amplitude envelope
Spectrum envelope
Tasko SPPA 6010 Advanced Speech Science

30. Tasko SPPA 6010 Advanced Speech Science
Amplitude envelope
Tasko SPPA 6010 Advanced Speech Science
From Hillenbrand

31. Tasko SPPA 6010 Advanced Speech Science
Spectrum envelope
Tasko SPPA 6010 Advanced Speech Science
From Hillenbrand

32. Amplitude Spectrum: Window Size
“instantaneous” amplitude spectrum
(long term) average amplitude spectrum
Tasko SPPA 6010 Advanced Speech Science

33. “Instantaneous” Amplitude Spectra
Tasko SPPA 6010 Advanced Speech Science

34. (Long Term) Average Amplitude Spectrum
Tasko SPPA 6010 Advanced Speech Science

35. Tasko SPPA 6010 Advanced Speech Science

36. Tasko SPPA 6010 Advanced Speech Science
The Spectrogram
Tasko SPPA 6010 Advanced Speech Science

37. Tasko SPPA 6010 Advanced Speech ScienceF A
Rotate
90 degrees F A
Tasko SPPA 6010 Advanced Speech Science

38. Tasko SPPA 6010 Advanced Speech ScienceF F
Rotate it so that
The amplitude is
Coming out of the
page
Time A
This is really narrow because it is a slice in time
Tasko SPPA 6010 Advanced Speech Science

39. Tasko SPPA 6010 Advanced Speech Science
Dark bands
= amplitude
Peaks F
Time
Tasko SPPA 6010 Advanced Speech Science

40. Two main types of spectrograms
Wide-band spectrograms
Akin to spectrum envelopes “lined up”
Frequency resolution not so sharp
Narrow-band spectrograms
Akin to amplitude spectrums “lined up”
Frequency resolution is really sharp
Tasko SPPA 6010 Advanced Speech Science

41. Tasko SPPA 6010 Advanced Speech Science
Highlights harmonic structure
Highlights spectrum envelope
Tasko SPPA 6010 Advanced Speech Science

42. Tasko SPPA 6010 Advanced Speech Science
Filters
What is a filter?
How are they relevant to speech?
Frequency response curve
Representing filter operation
Types of filters
Tasko SPPA 6010 Advanced Speech Science

43. Frequency Response Curve (FRC)
low
high
Gain + -
Center frequency
lower cutoff
frequency
upper cutoff
passband
3 dB
Tasko SPPA 6010 Advanced Speech Science

44. Operation of a filter on a signal
NOTE:
Amplitude spectrum describes a sound
Frequency response curve describes a filter
Tasko SPPA 6010 Advanced Speech Science

45. Source-Filter Theory revisited
Tasko SPPA 6010 Advanced Speech Science

46. Some frequency selective filters
Low-pass filters
High-pass filters
Band-pass filters
Tasko SPPA 6010 Advanced Speech Science

47. Tasko SPPA 6010 Advanced Speech Science
Resonance
What is resonance?
Free vibration
Forced vibration
Acoustic resonators
Resonance and speech
Resonators as frequency selective filters
Tasko SPPA 6010 Advanced Speech Science

48. Tasko SPPA 6010 Advanced Speech Science
Resonance and Speech
Tasko SPPA 6010 Advanced Speech Science

49. Resonators as frequency selective filters
Tasko SPPA 6010 Advanced Speech Science

50. Measuring signal amplitude
Amplitude vs. loudness
Sound intensity vs. sound pressure
Decibel scale
Linear vs. logarithmic
Absolute vs. relative
Reference values
Deriving the equations
Tasko SPPA 6010 Advanced Speech Science