The Benefits and Challenges of Amplification in Classrooms. CEFPI October 2012 Julie Wiebusch & Mark Rogers
CEFPI is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) earned on completion of this program will be reported to AIA/CES for AIA members. Certificates of Completion for both AIA members and non-aia members are available upon request. This program is registered with AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of each presentation.
Learning Objectives The Benefits and Challenges of Amplification in Classrooms At the end of this program, participants will be able to: 1. Understand how better hearing results in better learning. 2. Understand the need for proper design to ensure satisfaction. 3. Understand how acoustics is a critical element of the sound system. 4. Understand why acoustical privacy between classrooms must be improved.
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Sound is as much a part of man s man-made environment as heat or light. Vern Knudsen
Teaching and learning is dependent, to a great degree, on talking and listening
1 in 6 words not understood by 1st graders in classrooms with poor acoustics Canadian Language & Research Network Study (Bradley 2005)
Often unnoticed by administrators Teachers see the effects but may not realize the cause Poor classroom listening conditions = tangible lifelong impact on learning
Children can t learn if they can t see Children also can t learn if they can t hear and understand the spoken word
Students under age 13 are the most challenged The auditory physiology is immature until secondary school. As late as high school for some students Listening to Learn in a Sea of Noise: The Insidious Effects of Classroom Acoustics on Student Performance (Anderson 2007)
Lack the vocabulary needed to fill in the blanks
Students with some level of hearing impairment (some undiagnosed) Students with temporary hearing loss from middleear infections The speech perception accuracy and listening effort of non native English speakers is similar to children with hearing losses Place your hand over your ear to experience this level of hearing loss
28% of our nation s schools list noise as the #1 problem Noise causes some students to miss up to one-third of spoken communication in class Noise interferes with understanding speech Teachers attempt to compensate with raised voice levels Creates vocal fatigue in teachers Coalition for Classroom Acoustics
Children exposed to noisy learning environments: Trouble with word discrimination Cognitive delays Developmental delays Loss of concentration Tend to give up faster when faced with learning challenges.
for classroom design? AV Systems in every Classroom Sound Systems too! For program playback And for sound reinforcement (amplification of teachers)
Amplification everywhere? Well, maybe not Probably yes, if Room is large (over 50 or so seats) Room is noisy (full of computers) Special Ed: hearing impaired, foreign-speaking, etc. WSSP says yes, and give a point for it
Are Mediocre to Horrible!
Lecture Dry With Reverb Wordlist Dry With Reverb With Ambient With Both
Lack of understanding can affect speech perception, attention, behavior, and overall classroom performance
Teachers, administrators and parents are more skilled at listening in poor acoustical conditions
Talking loudly will NOT overcome high noise levels, even if the students are paying attention the average teacher takes at least two sick days per year related to vocal strain
2.9 million public school teachers in the U.S. Cost for substitute teachers was about $220 per day The national yearly cost for teacher vocal fatigue was estimated at $638 million If classrooms were designed well acoustically, that cost could be substantially reduced Acoustical Society of America (2000)
Won t amplification solve these problems? It is *one* tool to (maybe) improve listening conditions Probably not the most important one
What makes a sound system? Loudspeaker(s) Amplifiers and Things Microphone(s) THE ROOM Geometry Acoustics Noise
Why is that so important? Audibility Versus Intelligibility Loud is not good enough!
What noise? Mechanical and computer noise Intruding noise from outside the classroom Reverberation and echo Student noise Goal is 15+ db signal to noise Make signal louder, or Make noise quieter
Beware - Voice amplification will NOT improve listening in all classrooms! Reverberant Classrooms High Background noise Open plan teaching environment
amplification can be a big help Better intelligibility Improves comprehension Reduces student frustration Improve behavior
Amplification may not be sufficient for students with hearing impairment May require Assistive Listening equipment Wireless headset Hearing aid loop Must be provided to comply with ADA/ADAAG
You cannot fix poor acoustics or high noise with a sound system!
Documents Establishing Criteria WAC 246 366 110 LEED for schools 2009 Washington Sustainable Schools Protocol 2010 ANSI S12.60 2010 Part 1 & 2
WAC LEED Minimum Enhanced WSSP Required Improved ANSI Reverberation 0 ACT or ANSI 0 0.6 0.7 0 seconds 0.6 0.7 seconds Sound Isolation 0 0 STC 50 0 STC 50 STC 50 Background Noise NC35 / 45dBA 45dBA 40dBA NC35 / NC30 / 45dBA 40dBA 35dBA
Reverberation plays a critical role in the ability to understand speech. Highly reflective surfaces = more reverberation. This condition is described as Live. Sound in a highly reverberant room increases in level creating a noisy environment.
Reverberation is typically controlled by room finish Absorptive ceiling Wall treatment Carpet on floors
Reflected sound strikes one or more surfaces before reaching the hearer. The reflection patterns are dependent on the room shape In a performance space, the reflected sound is desirable. In classrooms, the reflections can be annoying and increase the overall noise level within the room.
Guidelines assume no amplification STC values may be unsatisfactory for amplified material Additional construction between classrooms may be necessary.
We often hear the term soundproof This is a misnomer - nothing is completely soundproof (or any other kind of proof ) There is also a misconception that insulation is the key element in reducing sound transmission. Mass Composite Elements Classrooms divided by operable partitions are especially challenging for amplified rooms
Watch for breaches in the sound isolation Through ceiling plenums Through light fixtures Through windows Through ductwork
Additional breaches in the sound isolation
Mechanical systems are typically the dominant source of sound and vibration in a classroom. Or they used to be..
Current design emphasis on passive ventilation systems results in very quiet room Quiet is good, too quiet is NOT Sounds from adjacent spaces are now more apparent Complicated further with amplification.
Environmental sources can also add to classroom noise
Common deficiencies of sound systems Poor coverage, feedback Wrong types of speakers In the wrong places Not enough speakers The worst case is 2 speakers! Classrooms usually have ceiling speakers, which are beamy like spotlights
Making it louder in one classroom makes it louder in the next May need better acoustical isolation Does not help students communicate with the teacher Unless you give a microphone to each student Wouldn t that be fun!
Design the room acoustics and sound system as one Have one loudspeaker, or many (never two) Mind the feedback Relationship of locations of microphone to speaker(s) Professional installation and tuning
Classroom Sound in a box Well, they are cheap Usually too few speakers (often 2!) Often poor quality One size does not fit all Beware of studies funded by folks selling audio equipment
Types of microphones Handheld Podium Lavaliere Headworn
Wireless microphones work great Unless you try to put one in a whole bunch of rooms in the same building Spectrum problems The battery problem Expensive! Radio versus Infrared
Using a microphone takes knowledge and practice! Be aware that everyone hates to hear their own voice Consider training workshops for teachers
Do it right, including acoustics, or skip it Remember old Abe If your budget is pinched, fix the acoustics first! Amplification with poor acoustics is usually NOT better than no amplification It could actually degrade intelligibility And add distraction
ANSI S12.60 2010 Part 1 and 2 http://asastore.aip.org/ -Free download! USGBC: LEED for Schools 2009 WAC 246-366-110 Primary and Secondary Schools Washington Sustainable Schools Protocol 2010 Edition
This concludes The American Institute of Architects Continuing Education Systems Course CEFPI Julie Wiebusch: e101, juliew@greenbusch.com Mark Rogers: e106, markr@greenbusch.com (206) 378-0569