HEARING INSTRUMENT SPECIALIST
CERTIFICATION 2025 STUDY GUIDE
QUESTIONS AND CORRECT ANSWERS|
ALREADY GRADED A+ 2025-2026
How do sound waves travel? Correct Answer In expanding
spherical patterns in all directions; the denser the medium,
the faster the sound will travel
What can reflection cause? Correct Answer Reverberation
or an echo
What happens to smooth walls during reflection? Correct
Answer They direct sound waves in a specific direction
What happens to rough walls during reflection? Correct
Answer They diffuse sound, reflecting it in a variety of
directions
Echo Correct Answer A sound reflection that arrives at the
listener's ear later than the original sound, and is heard
more than once
When do echoes occur? Correct Answer Any time sound
bounces off a surface
Why are echoes heard? Correct Answer Because the
reflected sound reaches the ear more than a 1/10 of a
second after the original sound was produced
,What are examples of materials that absorb sound?
Correct Answer Rubber, cork, and acoustic tiles
What materials improve the listening environment?
Correct Answer Soft pliable items like draperies,
upholstered furniture, and carpeting
What conditions are best for sound absorption? Correct
Answer Warm weather, and moist conditions
Diffraction Correct Answer Directional change of waves as
they pass through an opening, or around a barrier in any
medium
Which wavelengths have more diffraction? Correct Answer
Longer wavelengths (low-pitched sounds)
Which wavelengths have less diffraction? Correct Answer
Shorter wavelengths (high- pitched sounds)
Refraction Correct Answer A directional change of waves
as they pass from one medium to another
What changes during refraction? Correct Answer Speed
and wavelength (frequency) of the sound
Reverberation Correct Answer Collection of reflected
sound in an enclosure
, What determines the amount of reverberation? Correct
Answer Type of material found on room surfaces, and the
distance the sound has to travel to be heard by the listener
Early reverberation Correct Answer Sound that reaches
listener after a few reflections; enhanced comprehension
when listening with two ears
Late reverberation Correct Answer Sound that reaches
listener after several reflections; sounds like noise; it may
interfere with comprehension
What happens during a long reverberation time? Correct
Answer It becomes more challenging to understand
speech
Infrasound Correct Answer Sound waves with frequencies
below 20 Hz
Ultrasound Correct Answer Sound waves with frequencies
above 20,000 Hz
Noise Correct Answer Erratic, intermittent, or random
sound
What is fundamental frequency? Correct Answer The
lowest frequency produced by any vibrating body; first
harmonic (f1)
Harmonic Correct Answer Frequencies that are multiples
of fundamental frequency
CERTIFICATION 2025 STUDY GUIDE
QUESTIONS AND CORRECT ANSWERS|
ALREADY GRADED A+ 2025-2026
How do sound waves travel? Correct Answer In expanding
spherical patterns in all directions; the denser the medium,
the faster the sound will travel
What can reflection cause? Correct Answer Reverberation
or an echo
What happens to smooth walls during reflection? Correct
Answer They direct sound waves in a specific direction
What happens to rough walls during reflection? Correct
Answer They diffuse sound, reflecting it in a variety of
directions
Echo Correct Answer A sound reflection that arrives at the
listener's ear later than the original sound, and is heard
more than once
When do echoes occur? Correct Answer Any time sound
bounces off a surface
Why are echoes heard? Correct Answer Because the
reflected sound reaches the ear more than a 1/10 of a
second after the original sound was produced
,What are examples of materials that absorb sound?
Correct Answer Rubber, cork, and acoustic tiles
What materials improve the listening environment?
Correct Answer Soft pliable items like draperies,
upholstered furniture, and carpeting
What conditions are best for sound absorption? Correct
Answer Warm weather, and moist conditions
Diffraction Correct Answer Directional change of waves as
they pass through an opening, or around a barrier in any
medium
Which wavelengths have more diffraction? Correct Answer
Longer wavelengths (low-pitched sounds)
Which wavelengths have less diffraction? Correct Answer
Shorter wavelengths (high- pitched sounds)
Refraction Correct Answer A directional change of waves
as they pass from one medium to another
What changes during refraction? Correct Answer Speed
and wavelength (frequency) of the sound
Reverberation Correct Answer Collection of reflected
sound in an enclosure
, What determines the amount of reverberation? Correct
Answer Type of material found on room surfaces, and the
distance the sound has to travel to be heard by the listener
Early reverberation Correct Answer Sound that reaches
listener after a few reflections; enhanced comprehension
when listening with two ears
Late reverberation Correct Answer Sound that reaches
listener after several reflections; sounds like noise; it may
interfere with comprehension
What happens during a long reverberation time? Correct
Answer It becomes more challenging to understand
speech
Infrasound Correct Answer Sound waves with frequencies
below 20 Hz
Ultrasound Correct Answer Sound waves with frequencies
above 20,000 Hz
Noise Correct Answer Erratic, intermittent, or random
sound
What is fundamental frequency? Correct Answer The
lowest frequency produced by any vibrating body; first
harmonic (f1)
Harmonic Correct Answer Frequencies that are multiples
of fundamental frequency
