What are waveforms?
Time-by-amplitude displays
What are spectograms?
Time-by-frequency displays
Explain speech sounds in terms of air particles
Air particles are set in motion > the particles move from their rest position, disturbing neighbouring particles and setting them in motion > this reults in successive areas of compression and rarefraction > this way a wave propagates
Compression
Air particles closer together
Rarefraction
Air particles further apart
Two types of sound
- Periodic
- Apriodic (2a transient; 2b continuous)
What is a pure tone?
The simplest type of sound, which can be represented by a wave
Amplitude (waveform)
Maximum distance from starting point to peak
What does amplitude relate to?
Loudness (decibels, dB)
Frequency (waveform)
How many times a wave is repeated in a unit of time (Hz; 1Hz is 1 complete cycle per second)
Fundamental frequency (F0) calculated
Number of complete cycles of opening and closing the vocal folds per second
Frequency =
1/T (unit of time)
Humans can hear sounds in what frequency?
20-20,000 Hz (speech generally in lower half)
Which speech sounds are periodic?
Vowels and vowel-like sounds (nasals, approximants)
What are periodic speech sounds made up of?
Tones of several frequencies (harmonics)
What are harmonics?
Whole number multiples of F0
What are aperiodic sounds made up of?
They are comprised of many frequencies, but they are not multiples of an F0; irregular, non-repetitive waveform
What are transient sounds?
High amplitude, short-duration sounds; they occur with plosives in speech and are known as bursts
