2.05 - Environmental Acoustics Flashcards
Communication Breakdown: Speaker
Can improper stress/inflection, rate of speech, and/or volume cause communication break downs?
Yes
What are the four factors that can add to communication difficulties?
Speaker
Message
Environment
Listener
Communication Breakdown: Message
Can poor grammar, incorrect vocabulary, inaccurate information, and vague intent cause communication breakdowns?
Yes
Communication Breakdown: Listener
Can HL, topic infamiliarity, poor listening skills, low cognitive skills, and/or poor attention cause communication breakdowns?
Yes
Communication Breakdown: Environment
Can poor lighting and competing stimuli cause communication breakdowns?
Yes
Communication Breakdown: Acoustics
Can reverberation, noise, and/or distance cause communication breakdowns?
Yes
Noise should not exceed ______ in classrooms of 20,000 cubic feet or less
35 dBA
Reverberation Times should be _______ in unoccupied classrooms.
0.4 sec - 06 sec
SNR should be at least ______ at the child’s ears
+15 dB
What four things can affect speech perception?
Noise
SNR
Reverberation
Distance
What is noise?
Any unwanted sound or auditory disturbance that interferes with what the listener wants to hear
Does most communication take place in noisy environments?
Yes
Does the impact of noise increase with distance from the sound source?
Yes
Is speech the worse kind of noise?
Yes
Is the effect of noise greatest on those who are deaf or hard of hearing?
Yes
What are the three times of classroom noise?
External noise (outside the classroom - traffic, airplanes)
Internal noise (inside building but outside room - hallway, playground)
Room Noise (other students, ventilation, etc.)
What is the noise level in most classrooms
51 dBA
What is the recommended classroom noise level according to ASHA and ASA?
35 dBA
What is dBA?
Environmental sound levels
Reduces the the level of sounds at low frequencies
Which is stronger for positive SNR: the signal or the noise?
Signal
Which is stronger for a negative SNR: the signal or the noise?
Noise
Do those with SNHL have a greater need for a positive SNR? How much for non-reverberant rooms? How much for reverberant rooms? Average SNR?
Yes
+5 - +10 dB = Non-reverberant rooms
+8 - +16 dB = Reverberant rooms
+15 dB = Average
What does HINT stand for?
Hearing In Noise Test
How are sentences presented in HINT?
At different loudness levels by a female speaker
What is the noise level in HINT?
A constant 65 dBA
Does HINT test both ears?
Yes
What are the four different signal conditions used by HINT?
Speaker in front - quiet
Speaker from front - noise from front
Speaker in front - noise from right
Speaker in front - noise from left
Is the loudness of the signal varied in HINT according the the patients success rate?
Yes
At the end of HINT, you calculate how loud the signal needed to be in order to receive a score of _____%.
50%
If a 50% score is reached when the speech was 10 dB louder than noise, then the score is ____.
+10 dB
The higher the SNR, the ________ the patient has hearing in noise.
More difficulty
Do all children need a more favorable SNR than that needed by adults?
Yes
On an articulation index, 0.2 is ____ audibility. 0.8 is ____ audibility.
Low
High
What is the precedence effect?
Someone’s ability to suppress echo-like sounds that arise from sound bouncing off reflective surfaces
Do adults perceive a unified sound in reverberant rooms? Does this make it easier to locate the actual sound source?
Yes
Yes
Is the precedence effect present at birth? When does it develop?
No
Around five but is not mastered until late teens
Normal hearing children require a classrom SNR of _____.
+6
Do children with HL need a greater classroom SNR?
Yes
Do young children need a greater classroom SNR?
Yes
Do children learning a new language need a greater classroom SNR?
Yes
Do children with LDs or attention difficulties need a greater classroom SNR?
Yes
Do hearing aids amplify everything including noise?
Yes
Is there scientific evidence to show that hearing aid filters the attenuate noise?
No
Directional microphones can improve SNR by ____ dB.
5-8 dB
What is reverberation?
The prolongation of sound waves within a room as they are reflected off hard surfaces
What is reverberation time?
The amount of time it takes for a loud sound to decrease to inaudiblity
The amount of time it takes a sound to attenuate 60 dB following the termination of the signal
Why does reverberation create problems?
It masks the sound signal
Cause the prolongation of vowels which can mask consonants
Does speech perception decrease as RT increases?
YEs
Does sound fade quickly as distance increases?
Yes
The sound signal decreases _____ every time the distance from the sound source is doubled.
6 dB
What is critical distance?
Where the intensity of the sound source is equal to the intensity of the reflected signal
Do students with HL need to sit within critical distance?
Yes
In an average sized classroom with an RT of 0.6 seconds, what is critical distance?
3 meters
For normal hearing children in typical classrooms, does speech recognition decrease with increased distance?
Yes
Classroom noise should not exceed _____ dBA.
35 dBA
Classroom SNRs should be _____ or better.
+15 dB
In classrooms, RTs should be ______ unoccupied.
0.4 - 0.6 seconds
How can we improve classroom acoustics?
Reduce external noise levels
How can we reduce external noise levels in classrooms?
4
Work with architects and classrooms
Locate schools in quiet areas
Use double paned windows
Use well fitting doors
What are seven ways to improve room acoustics?
Put acoustic tiles in the hallway
Don’t install ventilation ducts that connect classrooms to each other or to the hallway
Move classrooms for deaf/hard of hearing students away from noisy areas: playgrounds, gyms, cafeteria, etc.
Install acoustic treatments
Control background noise
Place deaf/hard of hearing students away from room noise
Use preferential seating, small groups, ALDs
How can ALDs improve speech access?
They can reduce the effects of noise, reverberation, and distance
How much can ALDs improve the SNR?
15-20 dB
Is improving visual cues (making sure your face is visible) a way to improve speech access?
Yes
Which are better at improving SNRs: HAs or ALDs?
ALDs
HA cannot improve SNR