Acoustic Phonetics Test Flashcards
What is a sine wave?
A curve / continuous representing periodic contractions and rarerafractions. Shows the maximum deviation of a particle from its position of rest. X-Axis: Time. Y-Axis: Amplitude. Are perceived as pure tones.
What is a spectrograph/gram?
A spectrograph is a graph showing all three parameters of sound… X-Axis: Time. Y-Axis: Frequency and amplitude can be represented by the lightness/darkness/line intensity. Think LABBOOK They show the change of frequencies across time. Broadband spectrogram = best shows formants. Narrow band spectrogram= best shows harmonics.
What is a Spectrum?
A spectrum is a graph that shows the following two parameters of sound: X-Axis: Frequency. Y-Axis: Amplitude
Periodic Waves
Occur at regular intervals. perceived as musical sounds as they appear to the human ear. Can be sustained for longer. Can be both simple or complex sine waves.
Aperiodic Waves
Have no distinct pattern. Contain different frequencies. These sounds do not appeal to the human ear and will be considered noise/unpleasant. They also fade away quicker.
Four processes of speech production:
airstream, phonation, oronasal modification (resonance) and articulatory
Define the term “damping”
The reduction of amplitude due to the loss of energy. Very rapidly damped sounds are perceived as taps/clicks and known as transients.
Fundamental Frequency
Fundamental Frequency (in speech) is the lowest tone produced by the vibration o fthe vocal folds. The rate of the vibration of the vocal folds per second is the fundamental frequency otherwise known as F0.
What does amplitude correspond to?
Loudness
Harmonics
The multiple frequencies that make up a complex periodic wave are individually known as harmonics. The harmonics of a sound are perceived as its timbre (quality) .
What does timbre correspond to?
Voice quality, attributed to harmonic structure. The greater the range of harmonics, the richer the quality of sound.
Components of voice quality
Harmonic structure, breathiness, jitter, shimmer.
Hoarseness corresponds with…
Raised levels of jitter and shimmer
Mass, length and tension of the vocal folds determines the…
frequency of vibration. This explains the difference between pitch in adults, males, females, children.
Why do we describe pitch in terms of octaves/semitones?
Relates to human perception of hearing.
Is the LX waveform a sound?
No. The LX waveform is the data measured by a laryngograph. It measures the adduction of the vocal folds. Each cycle of the vocal folds is known as a pitch period.
Average adult pitch period…
adult female (median F0 = 200Hz) the pitch period would be expected to be circa 5ms (0.005 s), for an adult male with a median F0 = 100Hz, the pitch period would be expected to be around 10ms (0.010 s)
What is a CFx
The level of vocal fold irregularity perceived as creak. Represented as a cross-plot.
In an LX (laryngograph) waveform, the peaks getting closer together corresponds to…
An increase in fundamental frequency thus pitch- vocal folds opening and closing faster meaning pitch periods ae getting shorter
Difference between first order DFx and second order Dfx
. First order DFx takes into consideration every single pitch period and corresponds the fundamental frequency. Second order DFx – outliers are removed by only accepting two adjacent values/ values on a smooth contour. Typically, second order DFx will be smaller. Comparing the two can give an indication of irregularity and creak in the voice.
Frequency range of young, healthy human ear.
20-20,000Hz
Resonance
Phenomenon whereby acoustic system amplifies sound waves whose frequency matches one of its own natural frequencies of vibration. i.e. resonance occurs when on one or more of the frequencies in the sound source match the natural frequency of a cavity. In speech, there is more than one natural frequency in the vocal tract therefore speech sounds have more than one resonant value (known as formants) e.g. child’s swing- push will be amplified when push energy matches natural frequency of the swing
Laryngeal sounds
harmonics (resonant values) created by vibration of the vocal folds