2.2

Air particles move around their rest position in expected ways due to the forces of _____ and ______

elasticity; intertia

Recoil/Elasticity means that the displaced particles ________.

need to go back to rest

Inertia means the displaced particles ______.

keep going once they start moving in a direction

What are the 3 important measures of harmonic waves (sinewaves)?

frequency, amplitude, phase

What is the perceptual quality of frequency?

pitchWh

What is the perceptual quality of amplitude?

loudnessW

What is the perceptual quality of phase?

perceived location of sound source

frequency definition

the number of cycles that occur in one second

frequency application

more cycles per second equals a higher frequency and fewer cycles per second equals a lower frequency

What kind of relationship do cycles and frequencies have?

direct

amplitude definition

the amount of displacement of the air particle from rest

amplitude measurement

from rest to maximum displacement

amplitude application

a greater amplitude means a louder sound

What kind of scale is the decibel scale?

logarithmic

What is a logarithmic scale?

A logarithmic scale is a nonlinear scale used to measure values that can vary over a wide range, where each unit increase on the scale corresponds to a tenfold increase in the quantity being measured

Amplitude measures can be either ____ or ______.

vector; scalar

sound intensity level (dB IL)

vector measurement that measures the amount of sound energy and the direction of the sound energy

sound pressure level (dB SIL)

scalar measurement that is a measure of the amount of sound energy in a space

The human ear can detect sounds from ____ µPa (threshold of hearing) to ______ µPa (threshold of pain)

20; 20,000,000

Both the formula for intensity level and the formula for sound pressure level use a _____ level.

referent

Both of the referent values in the formula for intensity level and the formula for sound pressure represent _____ using different units of measure.

threshold of hearing

_______ is used in the clinic and it can be measured using three different devices.

sound pressure level

What are the three devices that are used to measure sound pressure level?

sound level meter, microphone, SLM app

What is a sound level meter?

a device that calculates the pressure of the sound wave(s) traveling through the air

What is a microphone?

a device that measures voltage changes

What is a SLM app?

an app that uses the microphone on your smart phone to calculate SPL

What are some general recording considerations?

• mouth to microphone

• microphone at 45 degree angle

• no background noise

• calibrate microphone

• sound level meter needs to be set to the weighting scale

What is weighting?

how the sound level changes the input

phase definition

description of where the particle is in relation to a reference point

phase application

sound waves sound different depending how “in phase” and “out of phase'“ they are from other sound waves