Aud Sci Flashcards
What will increasing stiffness result in?
Increased rate of vibration
What will increased mass result in?
Decreased rate of vibration
What happens when there are two sound waves and they have these properties:
both sound waves have the same amplitude
both sound waves have the same frequency
the two sound waves are 180o out of phase
Since they are exactly 180 degrees out of phase, they would cancel each other out
What is on the x-axis of a sine wave?
Time
What is a basic quantity?
The simplest quantities and they consist of time, mass, and length
What are derived quantities?
Any combination of basic quantities
What is a scalar?
Magnitude
What is a vector?
Magnitude and direction
What is simple harmonic motion?
Force is applied to the object
The object is displaced from equlibrium (inertial force)
The object reaches it’s maximum displacement
The elastic restoring force tries to bring it back to equilibrium
The object overshoots equilibrium and moves in the opposite direction (inertial force)
The object reaches its maximum displacement on the other side
The elastic restoring force tries to bring it back to equilibrium again
The object overshoots equilibrium and moves in the opposite direction again (inertial force)
This continues until friction eventually slows the object down and it returns to equilibrium again
How does sound energy travel from the source through air?
A force is applies to the tuning fork which causes it to vibrate in simple harmonic motion
The movement of the tuning fork displaces the air molecules around the fork
These air molecules begin with simple harmonic motion as well
These air molecules will come in contact with other air molecules as they reach their maximum displacement in the cycle of simple harmonic motion
These air molecules will also begin moving with simple harmonic motion
Since all of the air molecules are vibrating with simple harmonic motion, there are areas of rarefaction (low concentration) and areas of compression (high concentration)
This sequence of simple harmonic motion and stimulating surrounding air molecules continues until the sound from the sound source stops or until the distance from the sound source becomes too great and friction attenuates the movement of the air molecules
What is rarefaction?
Low concentration
What is compression?
High concentration
How is period calculated?
T=1/f
Does periodic sound have a tonal quality?
Yes
Is an aperiodic sound comprised of frequencies that have no particular mathematical relationship to each other?
Yes
Does a periodic sound have compressed harmonics?
Yes
Is a single pure tone periodic?
Yes
If a sound has a sound pressure level of 0 dB SPL, what is the pressure of that sound in micropascals?
20
What is pressure?
Force per unit area
Measured at a particular location away from the sound source
What is power?
Work per unit time
Property of the sound source
What is intensity?
Power per unit area
Describes the flow of sound
What is rms amplitude?
Average amplitude
What are harmonics?
Harmonics are multiples of the fundamental frequency, and individual components of a harmonic complex
What does it mean to say that sounds within a harmonic complex are harmonically related?
It means that sounds within a harmonic complex are multiples of the same largest common denominator (the fundamental frequency)
Which type of dB is greater, dB IL or dB SPL?
They are equal to each other
What is the log of 100?
2
What makes a psychoacoustic procedure adaptive?
It is dependent on the patient’s response to the previous stimulus
T/F: According to our current understanding of measuring perceptual sensitivity, a subject or patient would never respond to a stimulus presented below their measured threshold of sensitivity for that sound
False
Will someone with a liberal criterion present with thresholds that are relatively better or poorer?
Relatively better
Are shorter sounds ok for valid testing?
No, they are perceived more like a click
Need to be at least 200 to 300 ms
For normal hearing listeners, a doubling of loudness is approximately equivalent to an increase of how many dB?
10
What is the jnd for intensity?
1 dB or better, depending on the presentation level
What is the jnd for frequency?
Approximately 0.5% of the frequency
What is the jnd for duration?
As short as 2-3 ms
Why would the jnd be different at 2000 Hz than at 1000 Hz?
It is based on a percentage of the original frequency
What are 4 factors that affect threshold estimation?
Internal noise, attention, understanding of test, variable magnitude of stimulus
What are the 5 parameters for measuring thresholds behaviorally?
- Starting level
- Stopping rule
- Step size
- What is determining threshold
- How is the sound presented (medium)
True or false: loudness perception is dependent upon the frequency of the stimulus
True
Review loudness growth curves
What is the phon scale?
There is no particular relationship implied with 10 of this unit and 5 of this unit
What is the sone scale?
10 of this unit would be double the loudness of 5 of this unit
Is SPL pretty much always more than HL?
Yes
Review question 18 on exam 2
What is differential sensitivity?
Test that assess the smallest detectable difference between two stimuli that vary in sound pressure
What is absolute sensitivity?
Test that assesses the least amount of sound pressure level at which a subject responds 50% of the time
If we wanted to understand how much to increase a sound level for it to be perceived as double the original sound, what method would we chose?
A direct scaling procedure
The cochlea is nonlinear, meaning that the amount of gain differs based on input level. Is more gain applied at low-level inputs, mid-level inputs, or high-level inputs?
Low level inputs
Review question 22 on exam 2
T/F: 30 dB SPL is a doubling of the pressure from 15 dB SPL.
False
For listeners with normal hearing, a doubling of loudness is approximately equivalent to an increase of how many dB?
10
In regards to human hearing, what does a dynamic range refer to?
The range between the least audible sound and the highest tolerable sound
Is the human auditory system is equally sensitive at all frequencies between 20 Hz and 20,000 Hz?
No
What frequency range is the auditory system most sensitive?
1000-5000 Hz
Review attenuation rate (question 32 on exam 2)
What makes a psychoacoustic procedure adaptive?
Presentation level (or level that you present to the patient next) is based off of their previous response
What are the perceptual correlated to the big three dimensions of sound (amplitude, frequency, and phase)?
Loudness, pitch, and duration
What are two characteristics that must be present for something to vibrate?
Mass and elasticity
What will happen to the sound when the barrier is small relative to the wavelength?
The sound will scatter around the barrier and fill in behind it
What will happen to the sound when the barrier is large relative to the wavelength?
There will be an acoustic shadow on the other side of the barrier
What will happen to the sound when the opening is small relative to the wavelength?
The sound will pass through the opening and scatter as if new sound source
What will happen to the sound if the opening is large relative to the wavelength?
The sound will pass through the opening unchanged
What is transient distortion?
Spectral splatter
What is harmonic distortion?
Distortion products are added, which are harmonics of the original signal
What is frequency distortion?
Amplitude is reduced at certain frequencies based on the characteristics of the filter
Pitch is perceived based on maximum excitation along the basilar membrane. Place or temporal model?
Place
Bundles of auditory nerve fibers fire at the compression phase of a signal, giving the brain a cue for the period of the signal. Place or temporal model?
Temporal
Based on spectral representation of the stimulus (information contained in the spectrum). Place or temporal model?
Place
Based on the waveform of the stimulus. Place or temporal model?
Temporal
What is the upward spread of masking?
Increasing intensity of a low frequency sound is more likely to mask high frequency sounds, based on the anatomical structure of the basilar membrane. Due to the fact that high frequency sounds come first (as sound is moving down the cochlea), it has to pass high frequency areas before reaching low frequency areas, making it more likely for masking to occur
What is binaural fusion?
The brain receives information from both ears yet the stimulus is perceived as a single auditor image
What is binaural summation?
Performance is better on perceptual task when stimuli are presented binaurally vs monaurally
How do you avoid spectral splatter?
Use a 20 ms ramped rise time/fall time
What is harmonic distortion result from?
Input level exceeding max output level
What is ANSI?
A standard being referenced
What is the rejection rate or attenuation rate?
The slope of the filter
What Is RETSPL?
The value for converting dB SPL to dB HL
If you increased the stiffness of the middle ear system, would the result be a low frequency hearing loss or a high frequency hearing loss?
Low frequency
What are 4 things that happen when a sound wave encounters an obstacle or barrier?
Defraction
Absorption
Reflection
Transmission
What is defraction?
An obstacle or opening that will cause sound energy to scatter, pass through, go around, or fill in behind
What is absorption?
A medium that will absorb sound energy and result in attenuation (such as sound paneling or soft furniture)
What is reflection?
A medium that reflects sound energy (such as hard surfaces)
What is transmission?
The transfer of sound energy from one medium to another. More sound energy will transmit if the mediums are similar (sound energy in air will not transmit a lot of energy to water)
If a sound is located at 180 azimuth, where is the location of the sound?
Behind the head
What does it mean when we say the cochlea is modeled as a bank of overlapping filters?
Each place along the basilar membrane will respond at very low levels to a “best frequency” but will respond to other frequency inputs at higher levels
What is the better ear effect?
The SNR at one ear is more favorable than the other
What is binaural squelch?
The auditory system takes advantage of information received from both ears with different SNRs
What is the masking level difference?
Signal threshold is improved when tones to each ear are out of phase
What is echo suppression?
Copies of sounds in a reverberant room do not interfere with hearing because of this
A sound 15 feet from the source measures 14 dB SPL. Assume you are measuring in the free field. How would you calculate the sound level in dB SPL 30 feet from the source? How would you calculate the sound level in dB SPL 60 feet from the source?
You subtract 6 dB SPL for every doubling of distance. For 30 feet, the sound level would be 8 dB SPL and for 60 feet it would be 2 dB SPL
What is diotic?
The signal delivered to each ear is exactly the same in all aspects
What is dichotic?
The signal delivered to each ear differs in one or more dimensions
The duration of a signal can (but may not always) affect what in terms of perception?
Absolute threshold
Loudness perception
What is 90 degrees elevation?
At the top of the head
What is admittance?
The ease with which energy flows
What is impedance?
The opposition to energy flow
What is immittance?
The flow of energy
Guitar string after being plucked. Free or forced vibration?
Free
Tuning fork after being hit with a soft mallet. Free or forced vibration?
Free
Ossicles vibrating because of music. Free or forced vibration?
Forced
Table vibrates when the stem of a vibrating tuning fork is placed on it. Free or forced vibration?
Forced
What is the method of adjustment?
The patient or study participant has control over the stimulus level
What is direct scaling?
The patient is asked to give a rating of each stimulus
What is the method of limits?
Threshold is estimated using a series of ascending and descending runs with pre-determined starting levels
What is the method of constant stimuli?
Stimuli are presented in random order, with multiple trials per level
If your patient has a reduced dynamic range, what is their likely hearing loss, conductive hearing loss or cochlear hearing loss?
Cochlear
What is the reflection description of a plane surface?
The angle of the incident wave is the same as the reflected wave
What is the reflection description for a concave surface?
The reflected sound waves are focused
What is the reflection description for a convex surface?
Reflected sound waves are scattered
Does a narrowly tuned system have low levels of resistance?
Yes
Does a broadly tuned system have high levels of resistance?
Yes
Does a broadly tuned system make a good transducer of sound?
Yes
Does a narrowly tuned system have a relatively small bandwidth?
Yes
Does a broadly tuned system have a relatively large bandwidth?
Yes
What sounds does ILD localize?
High frequency sounds on a horizontal plane
What sounds does HRTF localize?
Broad band signals on a vertical plane
What sounds does ITD localize?
Low frequency sounds on a horizontal plane
If you increase the length of a tube, what happens to the resonant frequency of the tube?
It becomes lower
Review question 39 of final
