Speech & Hearing Science: Quizzam #2 Vocab

Reflection

waves that collides with a surface and travels back toward the source; the sound wave bounces backward off the boundary. (ex- a wave hitting a cement wall, and the energy reflecting back, like creating an echo in a canyon).

Destructive interference

waves that combine and decrease the amplitude of the resulting wave; a wave interferes with another wave such that a compression of one wave meets the area of compression of antoher wave, the net effect of which is to amplify the compression.

Constructive interference

waves that combine and increase the amplitude of the resulting wave; an area of rarefaction of a wave meets the area of rarefaction of another wave, the net effect of which is to amplify the rarefaction or an area of compression of a wave meets the area of compression of another wave, the net effect of which is to amplify the compression.

Decibel scale

a logarithmic ratio scale that compares the amplitude and/or intensity of a target sound to a standard reference sound; a logarithmic scale used to measure intensity.

Sound wave

a mechanical, longitudinal pressure wave that transmits sound.

Standing wave

a pattern, resulting from the interference of an incident and a reflected sound wave, that appears to stand still.

Power spectrum

a plot of the power (energy per unit of time) of given frequencies of a sound (same as a line spectrum).

Pulse wave

a single disturbance travels through a meduim.

Simple harmonic motion

a smooth back and forth movement with a characteristic pattern of acceleration through a rest position and deceleration at the end-points of the movement; uniform circular motion or periodic motion around a central equilibrium point.

Nearly periodic or quasiperiodic

a sound wave consisting of multiple frequencies in which the cycles do not take exactly the same amount of time to occur, but a repetitive pattern is apparent.

Complex aperiodic sound

a sound wave consisting of multiple frequencies in which the cycles do not take the same amount of time to occur (noise).

Complex periodic sound

a sound wave consisting of multiple frequencies in which the cylcles take the same amount of time to occur (a repetitive pattern is apparent).

Continuous spectrum

a spectrum that contains energy at all frequencies.

Mechanical wave

a wave that requires a medium to propagate itself, such as a sound wave.

Period

amount of time consumed by each cycle in a wave; the reciprocal of the frequency (1/f), the duration of one cycle.

Rarefaction

area of negative pressure; regions of decreased density of air particles, caused by restorative force and momentum.

Compression

area of positive pressure; the collision of air molecules result in regions of increased density.

Oscillation

back and forth movement of an object; vibration; back-and-forth cyclic movment about some point.

Interference

combining of waves in terms of areas of high and low pressure. (ex- when two singers sing the same note together, the compressions and rarefactions can lineup, creating a sound with a larger amplitude).

Absorption

damping of a wave with diminishing changes in air pressure due to friction. (ex-screaming into a pillow)

Wavelength

distance covered by one complete cycle of a wave; the distance traveled by one cycle of vibration.

Displacement force

force that causes a mass to be moved away from equilibrium.

Restorative force

force that causes a mass to return to equilibrium.

Harmonics

frequencies above the fundamental frequency in a complex periodic sound, which are integer multiples of the fundamental frequency.

Supersonic

frequencies above the human range of hearing (above ~20,000 Hz).

Subsonic

frequencies below the human range of hearing (below ~20Hz).

Line spectrum

graph in which the frequencies in a complex periodic sound are depicted as vertical lines, where the height of the line indivates the amplitude of the component frequency; the energy at each frequency is represented by a vertical ine, the height of which corresponds to the relative amount of energy.

Spectrum

graph with frequency on the horizontal axis and amplitude on the vertical axis; line spectrum represents periodic sounds, continuous spectrum represents aperiodic sounds.

Waveform

graph with time on the horizontal axis and amplitude on the vertical axis.

Threshold of pain

intensity level of 130 dB, which causes a sensation of pain in the ears.

Inverse square relationship

intensity varies inversely with the distance from the source; whatever factor by which the distance is increased, the intensity is decreased by a factor equal to the square of the distance change factor.

Boundary

interface between two mediums.

Envelope line

line that connects the frequencies of a complex sound represented on a spectrum; the contour formed by the display of energy at each frequency represented in a sound wave (aka spectral envelope)

Fundamental frequency

lowest frequency of a complex periodic sound; the repetition frequency of a sine wave or a complex pattern.

Fourier analysis

mathematical procedure to identify the individual sinusoids in a complex sound; a complex mathematical process of decomposing a complex wave into its separate sine waves; a method to transfer the time-series speech waveform into a frequency-based spectrum.

Cycles per second

number of cylces of vibration occurring in one second, equivalent to frequency.

Vibration

oscillation, a back-and-forth cyclic movment about some point.

Wave front

outermost area of the sound wave propagating spherically through the air.

Intensity

power per unit area.

Reverberation

process generating a sound that lasts slightly longer due to interaction of incident and reflected waves. (ex-singing in the shower)

Sine wave/ sinusoid

pure tone with a sinusoidal shape on a waveform; the simplest waveform, representing circular motion.

Auditory area

range of human hearing from threshold of hearing to threshold of pain; in terms of frequency, ranges from 20-20,000 Hz; in terms of intensity, a wide range, but best hearing occurs in mid-range.

Frequency

rate of vibration of an object; the rate at which particles vibrate back and forth per second.

Frequency

rate of vibration of an object; the rate at which particles vibrate back and forth per second; the number of cycles per second of a sound wave.

Phase

relative timing of compressions and rarefactions of waves; the point in the cycle of vibration of which the waveform begins.

Linear scale

scale by which successive units increase by the same amount.

Logarithmic scale

scale in which successive units increase by increasing amounts; a scale based upon multiples of 10, such as the decibel scale; equal steps along the scale represent equal ratios between raw values.

Ratio scale

scale that describes relationships between quantities.

Threshold of hearing

sound that a pair of normal human ears can detect 50% of the time under ideal listening conditions.

Incident wave

sound wave generated by a vibrating object, the original sound wave emanating from the vibration source.

Boundary behaviors

sound waves responses to a change in medium (refraction, reflection, diffraction, transmission, absorption).

Standard reference sound

sound with an amplitude of 0.0002 dyne/cm^2 and intensity of 10^-16 W/cm^2.

Pure tone

sound with only one frequency; a sound wave consisting of energy at a single periodic frequency

Complex sound

sound with two or more frequencies; a sound wave consisting of two or more pure sounds.

Amplitude

the amount of displacement of an object from its rest position; the magnitude of oscillation; on a waveform, the height of the wave.

Refraction

the change in the speed and direction of a sound wave due to interaction with a boundary. (ex- when a sound wave traveling hits water. When the sound wave hits the water, the speed of the wave is different due to elastic and inertial properties of the medium, and therefore the wave also changes directions).

Transverse wave

the particles in the medium move perpendicularly to the direction of the wave.

Longitudinal wave

the particles of the medium move parallel to the direction of the wave;

Pitch

the perceptual correlate of frequency.

Loudness

the percptual correlate of intensity.

Reflected wave

the portion of the energy of a sound wave that returns back after meeting a boundary.

Diffraction

the sound wave bends around an obstacle withoug going through the boundary. (ex- sound bending around a nearly closed door).

Phon scale

unit of loudness on a psychophysical scale; a psychoacousitc scale for intensity that uses a 1000-Hz pure tone as the reference frequency; a perceptual, subjective scale for loudness.

Decibel (dB)

unit of measurement for sound intensity.

Hertz

unit of measurement of frequency (cycles per second).

Mel scale

unit of pitch on a psychophysical scale; a psychoacoustic scale for intensity that uses a 100-Hz pure tone as the reference frequency; a perceptual, subjective scale for loudness.

Aperiodic

wave in which cycles do not take the same amount of time to ocur; irregular sound wave, having no definite pattern of repeating cycles.

Periodic

wave in which each cycle takes the same amount of time to occur; repetition of a pattern of vibration at fixed intervals in time.