Chapter One Properties of Sound

Question 1

Amplitude

Answer 1

The Maximum extent of a vibration or oscillation, measured from the position of equilibrium.
-Amplitude is perceived as LOUDNESS or VOLUME

Simply is the loudness that a signal is produced at

Question 2

Amplitude range of human hearing

Answer 2

0 to 120dB
- Human speech is around 40dB
- Concert hall is around 80dB
- Jack Hammer & Rock Concerts are around 110dB
- 120+dB = PAIN

Question 3

Attack

Answer 3

Time taken for a sound to build up to its full volume when a note is initially sounded

Question 4

Decay

Answer 4

How quickly the sound levels off to a sustain level after the initial attack peak

Question 5

Decibel (dB)

Answer 5

The unit used for measuring sound-pressure level (SPL), signal level and relative changes in signal level is the decibel
- Decibel literally means 1/10th of a bell. A bell is a transmission measurment unit thats named after Alexander Graham Bell, inventor of the telephone

Question 6

Envelope

Answer 6

The characteristic variations in level that occur in time over the duration of a played note

Question 7

Frequency

Answer 7

The rate at which an acoustic generator, electric signal or vibrating mass repeats within a cycle of positive and negative amplitude.
- Frequency is perceived as PITCH

Question 8

Frequency Range of Human Hearing

Answer 8

20 to 20,000 Hz

Question 9

Haas Effect

Answer 9

Human pyschoacoustic phenomena of correctly identifying the direction of a sound source heard in both ears but arriving at different times.

Question 10

Harmonics

Answer 10

Frequencies that exist in addition to the fundemental frequency that is being played

Question 11

Masking

Answer 11

Phenomenon by which loud signals prevent the ear from hearing softer sound

Question 12

Overtones

Answer 12

Frequencies higher than the fundemental frequency
- overtones that are whole number multiples of the fundemental frequency are called “harmonics”
- Double multiples of the original frequency are “Musical Octaves”

Question 13

Phase

Answer 13

Time delay between two or more wave forms
- variation of phase measured in degrees
- Two waves completely out of phase (180 degrees) will cancel each other out

Question 14

Release

Answer 14

How quickly the sound will decay once the note is released

Question 15

Sound Pressure Level (SPL)

Answer 15

The acoustic pressure that is built up within a defined atmospheric area
- The higher the SPL the louder the sound

Question 16

Sustain

Answer 16

Duration of the ongoing sound that is generated following the initial attack decay

Question 17

The 4 sections of envelope

Answer 17

-attack
-decay
-sustain
-release

Question 18

The Fletcher Munson Curve

Answer 18

At levels less then 100dB, extreme high frequencies and extreme low frequencies must be boosted in order to be perceived equally as loud as 1kHz

Question 19

Velocity

Answer 19

the speed of something in a given direction
- the speed of sound is 1130 feet per second at 68 degrees Fahrenheit

Question 20

Wave Propagation

Answer 20

High Pressure compression waves push against areas of low pressure.
- a term used to describe the way waves travel or move

Question 21

Wavelength

Answer 21

The physical distance in a medium between the beginning and the of a cycle