Improving Classroom Acoustics handout

Bridging the AT Gap
Improving Classroom Acoustics: Low to High Tech Strategies
Diane L. Meyer & Mike Brummer
 That normal hearing children can miss as much as 1/3 of what their teacher says due to poor
classroom acoustics. Even in an acoustically ‘good’ classroom, children ‘receive’ 83% of a
teacher’s voice ‘signal’ when they are seated in the front row; 66% in the middle rows and only
55% in the back row. (Crandell & Smaldino, 1994)
A child's hearing abilities are not fully developed until age 15. Children cannot hear and
neurologically process what they hear the same as an adult. (Crandell1995; Flexer 2002)
The teacher’s voice drops 6 decibels for every doubling of distance meaning that children
seated in the middle to back rows have significantly greater difficulty attending to the teacher’s
verbal instruction.
Environmental Strategies
• Installing acoustical ceiling tile is the most effective way of absorbing distorted middle and
high frequency noise and improving speech perception ability.
• A ceiling height less than 12 feet is optimal for the listening environment.
• Suspend banners, student work, and hanging plants from the ceiling
• Carpeting
absorbs excessive reverberation of high frequency consonant sounds
dampens noise from students and movement of classroom furniture
• Use rubberized or resilient tile versus flat, reflective tile
• Use area rugs or carpeting for uncarpeted areas
• Drapes on the sides of windows absorb sound
• Keep windows closed to prevent outside sounds from entering the classroom
Walls and Doors
• Place rectangular extension rods in opposite corners of the room and hang a curtain
Creates round corners to reduce reverberation
Provides small storage area
• Place cabinets at angles in the corners –soften the fronts with fabric curtains on magnetic
rods or cover with cork boards
Seating and Furniture
• Place a drape or cork on the front of solid areas teacher’s desk
• Use curtains to cover/conceal open shelving units
• Use tennis balls or rubber chair leg caps on tables and chairs
• Think about traffic flow in the room: where is supplies kept in relation to your teaching
• Place noisy items (pencil sharpener) away from teaching areas
• Create assigned zones during small group work so that groups are spread out
• Replace noisy blowers
Bridging the AT Gap
• Cover ventilation openings with strips of material
• Do not use desk or floor fans
• Make sure florescent lights are functioning correctly
Ballast will make high frequency sounds when they begin to burn out
• If your room is equipped with a motion sensor, position students with hearing aids out of
the directional path of the doorway
Special Purpose Areas
• Carpeting
• Use rubberized or resilient tile versus flat, reflective tile
• Hang banners or flags from the ceiling
• Place material or cloth banners on the walls
Instructional Strategies
Rate of Speech
Immature central nervous system needs a slower rate of speech in order to process
the acoustic linguistic code
 PK to 3rd grade need 120 words/minute
 4th grade can process 124 to 128 words /minute
 Middle school can process 135 words per minute
 High school can process 145 words per minute
Model a Preschool or Kindergarten teacher rate
Repeating of peers’ questions, comments, answers
Inverse Square Law – signal decreases 6 dB every time distance doubles
Students 20 feet from speaker will function like a person with a mild hearing loss
Repeat/Rephrase/Summarize all verbal communications
Control competing background noise
Close doors
Turn off radios
Use headphones for computer centers
Face students when speaking
Address the students when instructing
Speech signal travels through the air to the students’ ears versus traveling to the
board reflecting off the board
Allows students to access the speaker’s face for any visual support
Talk at a normal volume level
Increasing the volume increases the distortion of the auditory signal
Increasing the volume alters how you produce speech sounds making it difficult to
Technological Solutions
Soundfield Systems
• Surround sound systems for teachers and students
• Group or classroom systems for instruction of large audiences
• Personal systems for individuals with hearing loss
• Can be wired or portable