Lecture (2/15) Week 5 Thursday Flashcards
Reflected waves can ________ in a medium
interact with the original waves
What are the 3 examples of reflection?
standing waves
destructive interference
constructive interference
What is a standing wave
An example of reflection where the 2 waves are identical except they are out of phase, so they cancel out and create a dead spot
What is a destructive interference
An example of reflection where the amplitude lessens
-complete destructive interference creates standing waves: appears as if the vibrations are standing still
What is constructive interference
amplitude of interaction is increased
Absorption minimizes _____ and reduces ______
transmission, reflection
During absorption, energy is ____ and dissipated in the form of _____
absorbed, heat
What materials are best for absorption?
-soft, porous material
-acoustic tile
-egg cartons
-sound baffels
Sound baffles increase _____ and ______ and descreases ______ and _________
absorption and reflection
transmission and diffraction
Absorption ______ deadspots
reduces
Diffraction is when
sound goes around an object
Diffraction is dependent on the _____ and _____ of an object
wavelength and size
T/F diffraction can either be wanted or unwanted
True
What is the doppler effect?
apparent change in pitch of a sound caused by the** movement of a sound source**
How is the doppler effect explained?
As source moves closer to the listener, the sound waves are compressed, pitch is perceived as higher because frequency increases
As sound moves by and away from the listener, the sound waves are stretched and pitch is perceived as lower because frequency decreases
In the doppler effect, the original sound wave is still being produced at the ______
same frequency
What is an example of the doppler effect?
a car or train going by a stationary listener
What is the doppler effect equation?
fâ= f (S/S -Ss)
fâ altered frequency
f original frequency
S speed of sound
Ss speed of moving sound source
What is the inverse square law?
every time the distance from the sound source is doubled, the dB decreases by 6
T/F the inverse square law only takes place after the 1st meter
True
Why does inverse square law happen
The farther the sound gets from the source, the energy is spread over a larger area
-this decreases the energy, decreasing the intensity
What is a sound field
environment in which sound exists
what is a Soundproof or anechoic sound feild
no echos
hearing testing, we use a sound treated booth. It has a high degree of _____ and very little _______
absorption
reflection
Free field
Idealistic environment without any obstacles or barriers
A free field has no _____,______ or ______
reflection
absorption
diffraction
A near field is within _____ meter
has no _________
no decrease in _______
and acts as a ________
1
inverse square law
amplitude
free field
A far field is further than _____ meter
_____ , ______, and ______ are possible
______ applies
1
diffraction, absorption, reflection
inverse square law
