CSD 310 Sound Waves & SHM, Properties of Sound, and Waves

Parallel

In a longitudinal wave, the particles of the medium move _________ to the direction of the wave. These are the waves for speech.

Transverse Waves

In ______________, the vibration is perpendicular to the motion of the wave

Pressure

A sound wave disturbance is a ___________ change in any given medium. It is the result of changes in density

Compression

The areas of a sound wave with high pressure and low velocity

Rarefaction

The areas of a sound wave with low pressure and high velocity

Sine

Sound forms ______ waves

Pure Tone

A tuning fork creates a sound known as ______________

Wave

With sound waves, energy is carried by the __________

Frequency, Amplitude, Phase

Characteristics of a Sine Wave

Frequency

The number of complete cycles per second; the rate the particles oscillate each second.

Second

The frequency of a sound wave is the rate at which the particles vibrate back and forth each __________

Hertz

Frequency is measured in cycles per second or ________

Pitch

Frequency (a physical event) correlates to the ______ (a sensation) of a sound

Amplitude

The amount of vibratory displacement (how far an object moves describes this)

Loudness

Amplitude (a physical event) correlates to the ____________ (a sensation) of sound.

Phase

The starting _______ of a sine wave is the point at which the object begins to vibrate

degree of angle

Phase is typically defined in terms of ______________

Wavelength

The distance traveled in one cycle ( = speed / frequency)

Inverse

Wavelength has an _____________ relationship to frequency

Longer

Lower frequency, ____________ wavelength

Shorter

Higher frequency, ____________ wavelength

Period

The amount of time taken to go through one cycle of compression and rarefaction

One cycle

Period: the amount of time a vibration takes to complete _____________

Intensity

Energy (power) is the size of the local disturbance (compression and rarefaction of air molecules)

The greater the displacement of moles, the greater the energy imparted to them

Power per unit area (watts/m² )

amplitude of the sound pressure wave

Inverse Square Relationship

The relationship between distance and intensity; as one quantity increase the other decrease by an amount equal to the square of the distance change amount

ex. if the distance from a sound source is doubled (x2), the intensity is reduced by 4 (the square of 2)

Sound Pressure

The amount of force active over a unit area of surface

dyne

The unit of force used in acoustics

Loudness

Sound pressure and intensity (physical properties) while measured on different scales correlate to the _____________ (a sensation) of sound

Linearly

Intensity and loudness are NOT _______ related. Small increases in sound pressure yield large increases in intensity

Medium, phase

The speed of sound is determined by the __________ and it’s _______ (the tighter the bond, the faster the sound)

Decibels

Hearing and hearing loss as well as speech intensity is measured in __________

Decibel (dB)

An intensity ratio between sounds (10 times the logarithm to the base of that ratio)

0 dB

The reference value; the softest sound heard by the human ear. It does not mean there is no sound.

Standard

The important thing about measuring the intensity of a sound is that there is always a ____________

Ratio

The decibel is a unit of intensity that is a _______ or comparison of the sound in question with a reference sound.

Decibels Hearing Level (dB HL)

How sound compares to the softest sound the average person with normal hearing can just barely detect. A comparison of normal vs abnormal.

This is used for hearing tests

Poorer hearing

With Decibel Hearing Level, higher numbers = ______________ (or a intensity that is needed to elicit a response)

Decibels Sound Pressure Level (dB SPL)

How much pressure sound exerts. A measure of physical intensity ration.

Higher numbers = higher intensity

125-8000 Hz

The average range for speech energy. People can hear below and above these frequencies.