Number time
If patient's threshold for speech is 20 dB HL and you want to do a test at 40 dB SL where would you set the intensity dial (attenuator)?
(include the correct dB label in your answer!)
60 dB HL
Given frequency, what is the formula for finding period?
t=1/f
A sine wave is a graph representing what?
(2 possible answers)
1) the movement of one air molecule when hit by a force (cycles of condensation and rarefaction)
2) many air molecules creating a sound wave when moving through the air
We perceive frequency as ________
pitch
Draw a sine wave that changes in amplitude.
big wave and small wave
If the speech signal is 60 dB SPL and the noise is 40 dB SPL, what is the signal to noise ratio (SNR)?
+20 SNR
If it was 40 dB SPL speech and 60 dB SPL noise, -20 SNR
(speech - noise = SNR)
Given period, what is the formula for finding frequency?
f=1/t
Why does sound travel fastest through steel?
Molecules are denser
What is the definition of frequency?
cycles per second
Draw a sine wave and label 180 degrees
where sine wave crosses midline
(0 deg, 90 deg, 180 deg, 270 deg, 360 deg)
If you are testing patient at 30 dB SL and you have the intensity dial (attenuator) set to 90 dB HL, what is the patient's threshold for speech?
60 dB HL
given frequency, what is the formula for finding wavelength?
w=c/f
What force moves an air molecule PAST its point of rest? (hint: this is also the physical property of all matter which allows a body in motion to remain in motion and a body at rest to remain at rest)
Inertia
If there are 1500 cycles of displacement of an air molecule per second, what is the frequency of that sound?
1500 Hz
Draw a sine wave that shows wavelength (label both the x and y axis)
X axis: distance
y axis: amplitude
(for period, x axis is TIME and y axis is amplitude)
If the teacher's voice is 63 dB SPL at 2 ft, what is the dB SPL at 8 ft?
51 dB SPL
(2 to 4 ft: -6 = 57 dB SPL)
(4 to 8 ft: -6 = 51 dB SPL))
in the formula for finding wavelength, what does "c" always equal?
344 m/sec
(Plot twist! This is a virtually nonexistent connection to the category!)
What is an example of an aperiodic speech sound?
s, sh, f, th, v
Periodic sounds: vowels, 6000 Hz (any pure tone)
Aperiodic sound: noise/static
(NOTE: a sine wave best represents a periodic, simple tone, NOT a complex tone)
A mel graph shows that pitch and frequency correlate in what way in the low frequencies?
Pitch and frequency correlate linearly in the low frequencies (from 0-1000 Hz)
(directly in the high frequencies)
Draw 2 sine waves that differ in phase
think "pulse"
(lets look at a wave that differs in frequency vs wave that differs in phase)
what dB HL is the average level of conversational speech?
50 dB HL
what is the formula for converting dynes/cm2 to dB SPL?
extra 100 pts if you can tell me what the reference pressure is always equal to.
dB SPL = 20 x log (Po/Pr)
Pr = 0.0002 dynes/cm2
What is damping?
continual decrease of amplitude of a sound (air molecules hit with less force as time goes on)
Phon lines show what as a function of frequency?
loudness as a function of frequency
They show how much loudness/intensity you need across frequencies
Draw a sine wave and label elasticity
portion that goes towards center line