Audiology and Sound Physics Practice Flashcards

Vocabulary practice flashcards generated from audiology and acoustics lecture notes, covering scales of measurement, acoustic physics, wave propagation, interference, impedance, complex waveforms, and signal processing.

Science

The observation, identification, description, experimental investigation, and theoretical explanation of natural phenomena.

Nominal Scale

A scale of measurement consisting of named categories with no numerical value or relative order (for example, eye color).

Ordinal Scale

A scale of measurement consisting of ordered categories where the distances between ranks are unequal or unknown (for example, mild, moderate, and severe pain).

Interval Scale

A scale of measurement with ordered numerical values and equal intervals, but lacking a true physical zero point (for example, Celsius temperature).

Ratio Scale

A scale of measurement with ordered numerical values, equal intervals, and an absolute true zero point, allowing direct ratio comparisons (for example, number of siblings).

Logarithm

The mathematical inverse of an exponent; in base $10$, it answers what power $10$ must be raised to in order to equal a given number.

Decibel (dB)

A logarithmic unit expressing a ratio between a measured physical value and a standardized reference value.

Sound Intensity Level (dB IL)

A logarithmic intensity measurement calculated as $\text{dB IL} = 10 \times \text{log}(I_1 / I_2)$, where the reference intensity $I_2$ is $10^{-12}\text{ W/m}^2$.

Sound Pressure Level (dB SPL)

A logarithmic pressure measurement calculated as $\text{dB SPL} = 20 \times \text{log}(P_1 / P_2)$, where the reference pressure $P_2$ is $20\text{ }\boldsymbol{\breve{g}}\text{Pa}$.

Inverse Square Law

A physical law stating that sound intensity decreases inversely proportional to the square of the distance from the source; doubling the distance reduces intensity by $6\text{ dB}$ (to $\frac{1}{4}$ of the original power).

Physical Sound

Vibratory disturbances of molecules traveling as physical pressure waves through a medium, existing independently of an observer's ear.

Perceptual Sound

The psychological auditory experience created when sound waves enter the ear and are processed by the auditory system (encompassing pitch, loudness, quality, and location).

Mass

The physical amount of matter contained within an object or substance, measured in kilograms or grams.

Elasticity

The physical property of an object or medium enabling it to resist deformation and return to its original shape or resting position after being displaced.

Density

The mass per unit volume of a substance, defined by the formula $\text{Density} = \frac{\text{Mass}}{\text{Volume}}$.

Displacement

The net straight-line distance and change in position measured from an object's initial equilibrium position to its final position.

Restorative Force

The elastic force that pulls or pushes a displaced object back toward its baseline equilibrium position.

Elastic Limit

The maximum threshold of physical deformation an object can endure without sustaining permanent structural change or breakage.

Newton's First Law (Inertia)

The physical law stating that an object at rest remains at rest, and an object in motion continues in motion, unless acted upon by an external force.

Newton's Third Law

The physical law stating that for every applied force, there is an equal and opposite reaction force.

Brownian Motion

The continuous, random movement of air particles caused by constant collisions with adjacent molecules in an undisturbed medium.

Condensation (Compression)

A region in a sound wave where air molecules are pushed tightly together, resulting in elevated particle density and high sound pressure.

Rarefaction

A region in a sound wave where air molecules spread further apart, resulting in reduced particle density and low sound pressure.

Longitudinal Wave

A wave in which individual particle displacement occurs parallel to the overall direction of wave propagation (such as sound waves in air).

Transverse Wave

A wave in which individual particle displacement occurs perpendicular ($90^\text{o}$) to the direction of wave propagation.

Sine Wave

A smooth, repeating geometric waveform that graphically represents simple harmonic motion over time.

Frequency (f)

The number of complete oscillatory cycles occurring per second, measured in Hertz ($\text{Hz}$); it serves as the physical correlate of pitch.

Wavelength (̷)

The physical distance occupied by one complete wave cycle

Period (T)

The temporal duration required to complete one full cycle of vibration,

Amplitude

The overall size or magnitude of physical displacement of a wave from its baseline equilibrium line; it serves as the physical correlate of loudness.

Phase

The specific fractional position or angle of a waveform within one full $360^\text{o}$ cycle at a given moment in time.

Free Field

An ideal acoustic environment completely free of reflective surfaces where sound waves propagate outward without boundaries.

Diffuse Field

An acoustic environment containing multiple reflective surfaces that cause sound waves to continuously bounce, generating reverberation and echoes.

Constructive Interference

An interaction occurring when two sound waves combine in phase, adding their amplitudes together to produce a combined wave of greater magnitude.

Destructive Interference

An interaction occurring when two sound waves combine out of phase, subtracting their amplitudes to produce a combined wave of lesser magnitude.

Diffraction

The physical bending and spreading of sound waves around obstacles or through structural openings.

Head Shadow Effect

An acoustic phenomenon where the human head blocks high-frequency sound waves with short wavelengths, creating intensity level differences between the two ears.

Admittance

A measure of the relative ease with which sound energy flows through a physical acoustic system.

Impedance

The total vector opposition to the transfer or flow of sound energy through a physical acoustic system.

Reactance

The component of acoustic impedance caused by energy storage within a system, dictated by system mass and stiffness.

Resistance

The component of acoustic impedance caused by energy dissipation through friction, which operates independently of frequency.

Resonance

The tendency of a system to oscillate at maximum amplitude when driven by an external forced frequency that matches its natural resonant frequency.

Fourier's Theorem

A mathematical theorem stating that any complex acoustic waveform can be decomposed into a sum of individual sinusoidal pure tones.

Periodic Waveform

A wave that repeats an identical structural shape and pattern at regular temporal intervals over time.

Aperiodic Waveform

An acoustic wave displaying random, non-repeating energy fluctuations over time with no consistent structural pattern.

Waveform Envelope

The smooth macro-level outer boundary tracing the amplitude peaks of a complex wave, providing essential cues for speech comprehension.

Temporal Fine Structure (TFS)

The rapid micro-level pressure variations occurring within the envelope of a wave, crucial for pitch perception, timbre, and music appreciation.

Fundamental Frequency (f₀)

The lowest and principal frequency component contained within the acoustic spectrum of a complex periodic sound.

Harmonics

Whole-number integer multiples of the fundamental frequency ($f_0$, $2f_0$, $3f_0$, etc.) present in a complex periodic sound.

Spectrogram

A three-dimensional acoustic display plotting frequency on the y-axis, time on the x-axis, and signal intensity as visual shading density.

Nyquist Sampling Theorem

A signal processing principle stating that the minimum sampling rate must be at least twice the highest frequency component present ($f_{\text{sampling}} ≥ 2 \times f_{\text{max}}$) to digitize a signal without distortion.

Aliasing

A digital sampling distortion occurring when a signal is sampled below its Nyquist rate, causing high frequencies to misrepresent as lower false frequencies.

Quantization

The process of converting continuous analog amplitude measurements into discrete numerical digital values.

Dynamic Range

The total decibel span between the quietest detectable sound threshold of a listener and their upper limit of uncomfortable loudness ($\text{UCL}$).