MODULE 7A: NOISE

Question 1

What is defined as:

Any unwanted sound or any sound that interferes with the perception of a signal you are trying to hear?

Answer 1

NOISE

Question 2

Are pure tones considered”noise”? Yes or no. explain.

Answer 2

No they aren’t really noise because they aren’t very good with interfering with the perception of other sounds.

Question 3

Noise in acoustics and audiology is considered:

A) an pure tone
b) simple sound
C) complex sound
4) high frequency sound.

Answer 3

c) complex sound

Question 4

We use some pretty strange sounds during testing. Name the three forms of noise :

Answer 4

sawtooth noise
square waves
triangular wave

Look at picture in spa3030 folder Exam 3: “testing noise”

Question 5

A wave composed of a:

• fundamental frequency
• energy at each of the harmonics all starting at the same phase
• Amplitude of the harmonics decreases at a rate of 6 db per OCTAVE.
• With every doubling of frequency, the amplitude would decrease by 6 db .

……This is known as what wave?

Answer 5

a sawtooth wave

Question 6

sawtooth wave example:

If your fundamental frequency was 500 HZ at 70 db SPL, the second harmonic would be ???

Answer 6

• -second harmonic: 1000 HZ // amplitude of 64 db SPL.
• -third harmonic: 1500 HZ with an amplitude of 60.5 dB SPL
• -4th harmonic: would be 2000 HZ //Amplitude of 58 db SPL.

Question 7

What wave only has energy at the odd harmonics of the fundamental frequency that all start at the same phase? The amplitude also decreases by 6 db per OCTAVE. This wave is called?

Answer 7

A square wave

Question 8

What wave is made up of energy at the odd harmonics of the fundamental frequency, all starting at the same phase. Amplitude of the harmonics decreases by 12 db per octave, This wave is called?

Answer 8

The triangular wave.

Question 9

True//False:

Sawtooth noise, square waves, and triangular waves are all simple periodic sounds?

Answer 9

FALSE

THEY ARE COMPLEX PERIODIC SOUNDS

Question 10

What has energy of equal amplitudes at all frequencies. The starting phase of each component is random?

Answer 10

White noise

Question 11

If you are presented with a complex periodic sound waveform and need to figure out the fundamental frequency, do you rememebr what to do?

Answer 11

You need to find the period of the wave and then calculate the frequency.

Question 12

White noise is a complex periodic sound? T/F

Answer 12

False