Test 1 Flashcards
To produce sound, you need:
- a source (oscillations), ex: vocal folds
- a material medium (conduct), ex: air
A sound wave is a combination of:
- compression of air molecules
- rarefraction of air molecules
Compression:
Rarefraction:
- air molecules are closer together (+/peaks)
- air molecules are further apart (-/valleys)
Frequency (Hz)
refers to number of cycles per second
one cycle=one compression (+) and one rarefraction (-)
has an inverse relationship with period:
frequency=1/period
Human auditory system range of hearing (in Hz)
20-20,000 Hz
Period (time)
the time it takes to complete one full cycle of oscillation
has an inverse relationship with frequency:
period=1/frequency
Sound Intensity/Pressure Level
refers to the amount of sound energy
measured by Decibels (dB)
amplitude
Decibels (dB)
RELATIVE unit of sound
NOT absolute…therefore, 0dB does NOT mean absolute silence
Absolute Sound Pressure reference is
0.0002 dynes per sq. cm.
Fundamental frequency
Lowest frequency
Maximum amplitude
Spectral analyzer
does Fourier analysis
provides graphical plot that shows amplitude (y axis) over frequency (x axis) information
Waveform in a graph is
amplitude over time
Simple sound
aka Pure Tone
one frequency
Complex sound
more than one frequencies
Periodic
has a fundamental frquency
all additional frequencies are harmonically related to the Fo
can assign a pitch
ex: voiced speech sounds, piano notes
Aperiodic
does not have a fundamental frequency
other frequencies are NOT harmonically related
cannot assign a pitch
ex: voiceless speech sounds, book drop, waterfall
Two types of aperiodic
- transient (knock at door, gun fire, book drop)
2. continuous (waterfall, fan in classroom)
Vocal tract
a resonator (vibrating system) made up of:
pharynx, oral cavity, nasal cavity
average length: 17 cm
Formant frequencies (?)
frequencies of vowels
Spectrograph
electrical device used to obtain spectrogram
Spectrogram (?)
graphical plot of (y axis=)frequency over (x axis=)time
Resonance frequency
natural frequency of one’s specific vocal tract depending on the length, mass, density of that vocal tract
