classroom amplification to enhance student performance

Children learn a great deal through theauditory system. Classroom instructionis presented primarily through theteacher’s speech, or through video ortape recordings. Many students areauditory learners: They learn best wheninformation is presented to them verbal-ly. Students with hearing loss or otherlearning disabilities, however, may havedifficulty with comprehension of audito-ry information (Beattie & Zipp, 1990;Woglemuth, Kamhi, & Lee, 1998; seebox, “What Does the Literature Say?”).

What Are the AuditoryChallenges of InclusiveClassrooms? Legislation requiring the least restrictiveenvironment has resulted in a greaternumber of students being educated inthe general classroom. This inclusionconcept is intended to reduce the nega-tive effects of special education andresource room teaching (Kaufman &Pullen, 1996). Having to attend special

classes or receive individual tutoringmay cause the students to develop lowself-esteem because, unlike their class-mates, they need additional help tolearn. Also, teachers may become frus-trated when their teaching efforts areineffective in producing the desiredresult (Greyerbiehl, 1993). The assump-tion is made that these students are notmotivated or that they are lazy andunwilling to learn. According to RichardLevoie of the FAT City Workshop(1989), however, there are several legit-imate reasons for the student’s lack ofunderstanding: • Students with learning disabilities

have difficulty processing informa-tion. When asked a question in class,students with learning disabilitieshave to first process the questionbefore they can process an answer.This is different for students withoutlearning disabilities because theyonly have to process the answer, andcan respond to the question morequickly. During class it appears as ifstudents with learning disabilities donot know the answer or are not try-ing, when really they may just needmore time to process all the informa-tion.

• Students with learning disabilitiesoften can complete only one cognitive

task at a time. Because of this, theyfind it difficult to take notes in class.It is hard for these students to listento the teacher’s lecture and pick outthe important parts to write down.Often their class notes end up beingincomplete and hard to study fromwhen it comes to reviewing forexams.

• Reading aloud in class is also some-thing that students with learning dis-abilities can find difficult. Some stu-

20 ■ COUNCIL FOR EXCEPTIONAL CHILDREN

ClassroomAmplification

to Enhance StudentPerformance

Neil J. DiSarno

Melissa Schowalter

Patricia Grassa

What Does the Literature SayAbout Using Amplification

in the Classroom?

Research has shown benefits fromthe use of amplification devices inclassrooms of students whodemonstrate learning disabilities,as well as in regular classroomsettings (Arnold & Canning, 1999;Blake, Field, Foster, Platt & Wertz,1991; Flexer, Richards, Buie, &Brandy, 1994; Rosenberg, Allen,Redmond, Phillips, & Stigers,1995). Results of these studiesshow that the listening andattending behaviors of these stu-dents improved after implementa-tion of the amplification system.

Many students are auditory

learners: They learn best when

information is presented to

them verbally.

dents have spatial orientation prob-lems that cause them to confuse cer-tain letters such as p and q, and band d.If teachers are unfamiliar with the

problems associated with a specificlearning disability, they may misjudgethe student as being unmotivated orunwilling to learn. Unfortunately, thissometimes becomes a self-fulfillingprophecy, and students unable to learnmay become unwilling to learn. As welearn more about the difficulties thesestudents have and how to best educatethem, the student with a learning dis-ability can have a greater possibility of asuccessful educational experience.

What About Changing theClassroom Environment toReduce Noise?One way to improve the learning behav-ior of these students is to improve theireducational environment. Classroomstend to be noisy. This can be distractingto all students, but noise can have amuch more detrimental effect on thestudent with a learning disability.According to Blake, et al., (1991), stu-dents with learning disabilities have dif-ficulty maintaining their attention tostimuli. These inattentive behaviorshave been linked to the amount of noisepresent in the classroom. The studentwith a learning disability can havegreater difficulty tuning out backgroundnoise than the student without a learn-ing disability.

ASHA Guidelines

The American Speech-Language-Hearing Association (ASHA) Subcom-mittee on Acoustics in EducationalSettings developed guidelines foracceptable acoustical classroom envi-ronments (American Speech-Language-Hearing Association [ASHA], 1995).They reported that poor acoustical envi-ronments can affect the student’s atten-tion and listening behaviors, speechperception, and ultimately academicperformance. If a student also has ahearing loss, learning disorder, centralprocessing disorder, or developmentaldelay, the effects of the acoustical envi-ronment are even greater. Classroomnoise levels vary throughout the day,

depending on such factors as hall traf-fic, street noise through open windows,fans blowing, lights humming, over-head projectors in use, and generalnoise caused by a group of children.ASHA recommends that the averageunoccupied classroom should notexceed a 30-dB noise level. Averageunoccupied classroom noise levels,however, range from 45 to 60 dB. Whenclassrooms are occupied by studentsand teachers, these noise levels are evengreater.

Improving the Signal-to-NoiseRatio

Davis (1991) stated that children whohave difficulty factoring out distrac-tions, both auditory and visual, fre-quently are helped by an improved sig-nal-to-noise (S/N) ratio of the teacher’svoice. By increasing the volume of theteacher’s voice over the background dis-turbances, the child attends better andlearning improves. People with normalhearing require a +6 dB signal-to-noise(S/N) ratio, meaning that the speechsignal must be 6 dB louder than thebackground noise for it to be under-stood. But for students with a hearingloss or other disabilities, a higher S/Nratio may be required. ASHA recom-mends that the teacher’s voice be 15 dB

above the background noise in a class-room. Reports show the S/N ratio toactually range from +5 dB to -7 dB(Palmer, 1998).

Unfortunately, the average S/N ratioin the classroom can vary from -20 to+5 dB, depending on noise and rever-beration, and changes in teacher/stu-dent location (Richards, Flexer, Brandy,& Wray, 1993). These S/N ratios createa poor listening environment, not onlyfor the students with learning disabili-ties, but for other listeners, as well.

Effects of Noise Levels on Learning

Johnson (2001) reports that noise orecho can affect a student’s concentra-tion, causing misinterpretation of thelesson. If this happens often, learningsuffers, especially among students withlearning disabilities and hearing impair-ment. Downs and Crum (1978) exam-ined the effects of classroom noise lev-

TEACHING EXCEPTIONAL CHILDREN ■ JULY/AUGUST 2002 ■ 21

A teacher using the wireless microphone and transmitter system in theclassroom.

Poor acoustical environments can

affect the student’s attention and

listening behaviors, speech

perception, and ultimately

academic performance.

els on auditory learning. These authorsused measures of learning accuracy(performance) and learning ease (atten-tion or psychological effort) to assessprocessing demands during auditorylearning under degraded listening con-ditions. They found that auditory pro-cessing requires much more effort whenthe subject is listening in a noisy envi-ronment rather than a quiet one.Listening in a degraded acoustical envi-ronment, such as a classroom, requireseffort on the part of the student, and ifnot employed consistently, academicperformance may suffer. They foundthat simply increasing the overall levelof sound, while maintaining the sameS/N ratio, does not result in an increasein performance. A possible explanationis that processing demands during audi-tory learning depend on the relationshipof signal to noise, rather than absolutenoise level. Thus, it can be proposedthat no listener (hearing or hearing-impaired) is immune from deleteriouseffects of noise on auditory learning.

Concrete Ways to Improve S/NRatio

There are several ways to improve theS/N ratio in the classroom. Physicalmodifications can be made to the walls,windows, floors, and ceilings. Carpetingfloors and installing acoustical ceilingtile helps to absorb middle- and high-frequency sounds, reducing the rever-beration present in the classroom.Because the ceiling and floor compriseapproximately 60% of the classroomsurface area, these two modificationsalone can significantly improve theacoustical environment of the class-room. The most effective treatment for

windows is drapery, although blinds arean acceptable alternative.

Functional classroom furniture, suchas cork bulletin boards and bookshelvesplaced at strategic positions will reducereverberation within a classroom.Mobile bulletin boards and chalkboardsplaced at nonparallel angles to the wallswill aid in the reduction of reflectedsound. Children’s artwork made ofabsorbent materials, such as egg cartonsand carpet pieces, can also be displayedon walls or suspended from the ceilingto absorb noise, reducing reverberation(Crandell, Smaldino, & Flexer, 1995).However, these materials do not absorbclassroom noise as well as other morehighly absorbent materials.

Barriers to Improving S/N Ratio

Making physical changes to the class-room environment improves the S/Nratio by reducing the background noise,while the teacher’s voice remains thesame. But in most classrooms, teachersmove around the classroom or occa-sionally face the chalkboard, thusimpeding hearing by many students.

How Can Amplification SystemsHelp?A way to improve the S/N ratio withoutdirectly addressing these issues is to usean amplification system that increasesthe sound of the teacher’s voice andbrings the signal closer to the student’sear. Educators can use several amplifi-cation systems to improve the S/N ratioin the classroom, such as personal FMsystems, sound-field amplification,induction loop amplification, andinfrared systems. These devices improvethe S/N ratio by amplifying theteacher’s voice and sending it directly tothe listener’s ear.

Personal FM Systems

The personal FM system works byreceiving an audio signal which is fre-quency modulated onto a carrier wavethat is sent from the transmitter to thereceiver where it is demodulated anddelivered directly to the listener’s ear.The speaker wears a wireless transmit-ter which receives input from a micro-phone. The transmitter can also be con-nected to a television, tape recorder, or

radio. The listener wears a receiver,which can be attached to earphones,coupled inductively by a neckloop orsilhouette or coupled electrically viadirect audio input to a hearing instru-ment. FM systems can operate on asmany as 40 or more different channels,allowing different frequencies to beused in one school. Therefore, adjacentclassrooms can use FM systems withoutworrying about interference.

Sound-field Systems

The sound-field FM system is differentin that the signal is sent out to loud-speakers placed in the classroom. Theteacher still wears a microphone andwireless transmitter. The FM signal issent from the transmitter to an amplifi-er which is connected to one or moreloudspeakers. The transmitter can alsobe connected to a tape recorder or VCR,which improves the often degradedsound of these recordings. All studentscan benefit from use of sound-fieldamplification. Students with centralauditory processing disorders, minimalhearing loss due to otitis media, andunilateral hearing loss—and even hear-ing students—can benefit from receiv-ing a louder level of the teacher’s voice.

Benefits to Students

In addition to student benefits, there arealso significant benefits for the teacher.According to Gotass and Starr (1993),teachers experience a higher number ofvoice problems than the general popula-tion. Sapienza, Crandell, and Curtis(1999) found that FM systems in theclassroom can reduce a teacher’s overallspeech volume, thus limiting the poten-tial for voice problems.

Personal FM systems are typicallyprescribed for students with hearingloss and can be quite costly.Implementation of one sound-field sys-tem into the classroom costs consider-ably less than supplying personal FMdevices for all students. Also, there isless stigma associated with sound-fieldsystems because the students do nothave to wear something different fromtheir classmates. More students wouldbe willing to listen to the teacher’samplified voice through loudspeakersthan through a headset.


Educators can use several types of

amplification systems to improve

the S/N ratio in the classroom,

such as personal FM systems,

sound-field amplification,

induction loop amplification, and

infrared systems.

What Do Teachers ObserveAbout Amplification?The present study was an attempt todetermine the effect of teacher bias onthe results of classroom amplificationuse. Most studies that have examinedthe effects of group classroom amplifi-cation have used the observation of theclassroom teacher alone.

We hypothesized that teachers whoagree to undergo use of classroomamplification may already be convincedof its effectiveness. This may affect themanner in which they complete subjec-tive evaluations documenting behav-ioral changes following a period ofclassroom amplification.

The present study was performed ina classroom setting that used a two-member team-teaching approach. Bothclassroom personnel had been provid-ing services to the group of 9 studentsfor more than 2 years and were familiarwith all students in the class.Independent observations by each ofthe instructors were used to determine ifperformance changes occurred, and ifso, the extent to which each observerdocumented the change.

Classroom Installation

A Phonic Ear wireless FM classroomamplification system was installed in aclassroom for 9th- to 12th-grade stu-dents with learning disabilities for aperiod of 3 months. The Phonic EarSystem consisted of a wireless transmit-ter and microphone worn by theteacher. The speech signal was sent byFM signal from the transmitter to anamplifier plugged into a wall outlet.Loudspeakers were wired to the amplifi-er and mounted to the walls in each ofthe four corners of the student seatingarea. Ambient noise levels in the unoc-cupied classroom were measured to be49 dB(A).

The teacher’s nonamplified speakingvoice, measured 6 inches from hermouth, was 66 decibels. Under amplifi-cation conditions, the teacher’s speak-ing voice, measured 6 inches from eachof the loudspeakers, was 72 dB(A).Listening and learning behaviors wereindependently evaluated by the classroomteachers using the Listening and LearningObservation (LLO) form developed for

this project (Appendix A) and theEvaluation of Classroom ListeningBehaviors (ECLB) form adapted fromVanDyke (1985) (Appendix B). Teacherscompleted these forms before the installa-tion of the amplification equipment, againat 6 weeks of amplification use, and at thetermination of the project (12 weeks).

Results of Observations

Figures 1 and 2 shows the pre- and post-amplification scores for the ListeningBehavior section of the LLO evaluationfor Teacher 1 and Teacher 2.

The scores on the nine listeningbehavior characteristics rated on theLLO for all subjects were summed and


Figure 1. Listening Behavior of Students, Observed by Teacher 1,Before and After Amplification

Note: LLO = Listening and Learning Observation (see Appendix A).

Figure 2. Listening Behavior of Students, Observed by Teacher 2,Before and After Amplification


averaged across subjects at the begin-ning of the experiment, and again 3months later. Higher scores on the LLOindicate better performance, ordecreased difficulty on the behaviormeasured.

Each teacher independently ob-served student improvement in areassuch as ability to follow oral instruction,less need to repeat instruction, as wellas decreased reliance on assistance from

the teacher or peers when instructionswere given.

Figures 3 and 4 show the pre- andpost-amplification scores for theAcademic Behavior section of the LLOfor Teacher 1 and Teacher 2.

Results of this study show a signifi-cant improvement in students’ listeningand academic behaviors after 12 weeksof classroom amplification. This studyhas shown that the use of two inde-pendent evaluators can be a beneficial

method of evaluating subjects’ listeningand attending skills. The use of a sec-ond evaluator lends credibility to theresults, demonstrating that even if eval-uators do not agree in terms of initiallevel prior to amplification, they both doagree that there is improvement in stu-dents’ skills after use of the group FMsystem (for more information onresearch methodology and significancelevels, contact the authors).

The implementation of the sound-field system into the classroom requiredan adjustment period for both the stu-dents and the teachers. By the end ofthe study, the teachers and the studentswanted to continue using the FM sys-tem. We believe that this type of FM sys-tem requires less adjustment, especiallyby the students, because it is a wirelessspeaker system. Students may be lesswilling to wear a personal FM system;and a longer adjustment period, as wellas greater cost, would result from sucha system, as compared to the sound-field system.

Benefits and ClassroomImplications

Reports made by the teachers in thisstudy reveal that the main benefit ofamplification in the classroom was anincrease in the teachers’ ability to getand maintain students’ attention. Theobservations also reported a decrease inteacher vocal strain and fatigue. Bothteachers reported that they would con-tinue using the amplification in theirclassrooms and would recommend useof amplification systems in other class-rooms.

The classroom teachers reported thatthe students grew more interested in theFM system as the observation period


Figure 3. Academic Behavior of Students, Observed by Teacher 1,Before and After Amplification

Figure 4. Academic Behavior of Students, Observed by Teacher 2,Before and After Amplification



Students with central auditory

processing disorders, minimal

hearing loss due to otitis media,

unilateral hearing loss—and even

hearing students—can benefit

from receiving a louder level of

the teacher’s voice.

continued. By the end of the study, theteachers stated that students were com-ing to class eager to use the system, andwould have the system on and ready touse before class began. Also, the teach-ers stated that the system was useful forthe one student who was deaf in theclass, especially when watching videos.

Final ThoughtsMany educators have shown that class-room amplification can be useful in avariety of settings, including the generalclassroom, classrooms for students withhearing impairments, and classrooms forstudents with learning disabilities. Use ofgroup classroom amplification can be asimple and inexpensive way to improvemany students’ educational experiences.

ReferencesAmerican Speech-Language-Hearing Asso-

ciation (ASHA). (1995). Position state-ment and guidelines for acoustics in edu-cational settings. ASHA, 37(14), 15-19.

Arnold, P,. & Canning, D. (1999). Does class-room amplification aid comprehension?British Journal of Audiology, 33, 171-178.

Beattie, R. C., & Zipp, J. A. (1990). Range ofintensities yielding PB max and thethreshold for monosyllabic words forhearing-impaired subjects. Journal ofSpeech and Hearing Disorders, 55, 417-426.

Blake, R., Field, B., Foster, C., Platt, F., &Wertz, P. (1991). Effect of FM auditorytrainers on attending behaviors of learning-disabled children. Language, Speech andHearing Services in Schools, 22, 111-114.

Crandell, C. C., Smaldino, J. J., & Flexer, C.(1995). Sound-field fm applications:Theory and practical applications. SanDiego: Singular.

Davis, D. (1991). Utilizing amplificationdevices in the regular classroom. HearingInstruments, 42(7), 18-23.

Downs, D., & Crum, M. (1978). Processingdemands during auditory learning underdegraded listening conditions. Journal ofSpeech and Hearing Research, 21, 702-714.

Flexer, C., Richards, C., Buie, C., & Brandy,W. (1994). Making the grade with amplifi-cation in classrooms. Hearing Instru-ments, 45(10), 24-26.

Gotass, C., & Starr, C. D. (1993). Vocalfatigue among teachers. Folia Phoniatricaet Logopaedica (Basal), 45(3), 120.

Greyerbiehl, D. (1993). Educational policiesand practices that support the inclusion ofstudents with disabilities in the generaleducation classroom. Charleston: WestVirginia Developmental DisabilitiesPlanning Council.

Johnson, E. (2001). Let’s hear it for learning:Improving classroom acoustics can maxi-mize student productivity at a minimalcost. American School and University,73(11), 28-30.

Kaufman, J. M., & Pullen, P. I. (1996). Eightmyths about special education. Focus onExceptional Children, 28(5), 1-12.

Levoie, R. (Presenter). (1989). Understandinglearning disabilities: How difficult can thisbe? [Videotape]. (Available from PeterRosen Productions, Washington, DC).

Palmer, C. M. (1998). Quantification of theecobehavioral impact of a soundfieldloudspeaker system in elementary class-rooms. Journal of Speech, Language, andHearing Research, 41, 819-833.

Richards, C., Flexer, C., Brandy, W., & Wray,D. (1993). Signal-to-noise enhancingdevices can improve kid’s reading skills.Hearing Instruments, 44(11), 12-15.

Rosenberg, G., Allen, L., Redmond, B.,Phillips, J., & Stigers, K. (1995). Improvingclassroom acoustics, listening, and learningwith FM soundfield amplification. PosterPresentation at the American Academy ofAudiology Convention, Dallas, TX.

Sapienza, C. M., Crandell, C. C., & Curtis, B.(1999). Effects of sound-field frequencymodulation amplification on reducingteachers’ sound pressure level in the class-room. Journal of Voice, 3, 375-381.

VanDyke, J. (1985). Evaluation of classroom lis-tening behaviors. Rocky Mountain Journalof Communication Disorders. 1, 8-13.

Wolgemuth, K. S., Kamhi, A. G., & Lee, R. F.(1998). Metaphor performance in childrenwith hearing impairment. Language,

Speech, and Hearing Services in Schools,29, 216-231.

*To order the book marked by an asterisk (*),please call 24 hrs/365 days: 1-800-BOOKS-NOW(266-5766) or (732) 728-1040; or visit them onthe Web at http://www.clicksmart. com/teach-ing/. Use VISA, M/C, AMEX, or Discover orsend check or money order + $4.95 S&H($2.50 each add’l item) to: Clicksmart, 400Morris Avenue, Long Branch, NJ 07740; (732)728-1040 or FAX (732) 728-7080.

Neil J. DiSarno, Professor, Department ofCommunication Sciences and Disorders,Southwest Missouri State University,Springfield. Melissa Schowalter, LicensedAudiologist, Branson Ear, Nose, and Throat,Springfield, Missouri. Patricia Grassa (CECMissouri Federation), Special EducationTeacher, Springfield Public Schools, Missouri.

Address correspondence to Neil J. DiSarno,Department of Communication Sciences andDisorders, Southwest Missouri StateUniversity, 901 S. National Avenue,Springfield, MO 65804 (e-mail: [email protected]).

TEACHING Exceptional Children, Vol. 34,No. 6, pp. 20-26.

Copyright 2002 CEC.


Helpful Web Sites

http://www.classroomacoustics.comClassroom Acoustics: Resource for proposed standards for classroom acoustics.

http://pages.cthome.net/cbristolCAPD Parent’s Page: Provides resources for parents of children with auditory pro-cessing disorders.

http://www.phonicear.com/Phonic Ear: Products for FM amplification.

http://www.lifelineamp.comLifeline Amplification Systems: Describes Lifeline’s products, prices, and informa-tion about the company.

http://www.lightspeed-tek.com/Lightspeed Technologies: Contains information on company, products, and con-tact information.

Physical modifications can

improve the acoustical

environment of the classroom,

though these may be too costly.

Some equipment manufacturersoffer a free 30-day evaluation oftheir classroom soundfieldequipment to schools. Most sys-tems cost under $1,000; furtherinformation may be obtainedfrom the Web sites.


Appendix B. Evaluation of Classroom Listening Behavior

Adapted from VanDyke, 1985.

Appendix A. Listening and Learning Observation

classroom amplification to enhance student performance

Documents