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the listeninglearning link

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The teacher has just asked a questionabout last night’s homework. Wantingto encourage participation from thosewho rarely raise a hand, she decidesto call on Sally.

“Sally, where is the Rio Grande River?”

Sally looks at the teacher,perplexed. Did she just ask where the real train was driven?

This scenario is typical in the averageclassroom. According to the AcousticalSociety of America, “Students with normal hearing in the averageAmerican classroom miss 25% of what the teacher is saying.”

If you’ve ever taken a foreign languageclass or tried to converse at a loudparty, you know how exhausting it canbe. Trying to understand someoneunder adverse conditions such as distance, noise, reverberation and pooracoustics—all of which are a part of everyday life in our schools—make it extremely difficult for kids to focus on the teacher

Good speech intelligibility is crucial forthe development of auditory and lan-guage skills in all children. Many remainsilent about the difficulty they are havingdiscerning speech in the classroom. LikeSally, they may become confused, orworse— give up. Unfortunately, until theteacher or a family member begins to

identifying the need

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take notice of the real problem, studentslike Sally may be perceived as apatheticor incapable of learning the material.

the communication connectionStudies have proven that in noisy environments the more than 2 millionschool children learning English as asecond language (ESOL) have moredifficulty with speech perception thannative English speakers, especially if

they are seated in the middle to backof the classroom.

Fundamental to the problem is child-hood itself. Children’s auditory process-es are not fully developed until theirmid-teens, and they don’t have the lifeexperience to be able to “fill in thegaps” when they do miss information.

As we’ll see in the next section, noise, distance, and reverberation all exacerbate these fundamental problems.

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Distance is a significant obstacle tospeech understanding. Audibilitydecreases as the distance from thespeaker increases (about a 6dB drop for every doubling of distance). At acertain distance, the background noisecan effectively mask the speaker’s voice.

A typical teacher’s voice measures 60to 65dB at a distance of 1m/3ft. Thismeans that front-row students hear theteacher at 65dB, receive 83% of

speech signal, and can achieve95% word recognition.

Students in the middle row, however,hear the teacher at 59dB — alreadybelow typical classroom noise levels —receive 66% of the speech signal, andachieve 71% word recognition.

The situation is worse for back-row students, who hear the teacher at 53dB,receive 55% of the speech signal, andachieve just 60% word recognition.

distance

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Noise can cause a general breakdownof communication and missed infor-mation. For ESOL students thisbecomes especially true as they try —and often give up — discriminatingbetween competing background noise and the teacher’s voice.

Playground squeals, desk and chairmovement, chatting students, fans, andheaters all result in a typical noise levelof 60dB — almost as loud as busy streettraffic. And since a teacher’s comfortablespeaking volume is only 60dB at 3ft/1m,she has a difficult time simply beingheard by her pupils.

noise

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Noise and reverberation (alsoreferred to as echo) are synergis-tic. Hard walls, high ceilings, glass

windows, and uncarpeted floorsreflect many sounds, often witha negative impact on speech

understanding.

Reverberation timeshould be less than 0.4 seconds to avoid

decreasing intelligibil-ity, yet the typical classroom averages0.8 seconds rever-beration time.

Vowels — the low-frequencysounds representing 60% ofspeech energy, but only 5% of speech meaning — often maskthe weaker consonant sounds,which contain far more speechmeaning (compare cat, bat,sat, pat). As a personspeaks louder, the vowelsare emphasized, furtherobscuring meaning.

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Figures in boldface indicate acceptable WDS scores. Without a sound fieldsystem, these scores are achievable only in quiet or acoustically treated rooms. Also note that this chart does not consider distance; even in quiet, acoustical-ly treated rooms, children at the back will have compromised understanding.

Effects of Reverberation & Signal-to-Noise Ratio on Word Discrimination

Word discriminationscores of students with normal hearing

Classroom with carpet, curtains,some acoustic treatment

Typical classroom(no carpet, etc.)

Signal-to-Noise RatioQuiet Noisy

Reverb 20 +12 +6 0

0.0 95% 89% 80% 60%

0.4 93% 83% 71% 48%

1.2 77% 69% 54% 30%

reverberation

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signal-to-noise simplifiedAs we’ve seen, intelligibility is not thesame as mere audibility (i.e., simplyhaving the teacher speak louder is not the answer). In fact, intelligibility is directly related to signal-to-noiseratio (S/N) — the difference betweenambient room noise and the speak-er’s voice (the signal). The greater the S/N, the greater the intelligibility.

Let’s look at an example. Average classroom noise is 60dB. The averageteacher speaks at 60 - 65dB measuredat 3ft/1m. Thus, you would have +5dBS/N at a distance of 3ft/1m from thespeaker — and we know from the pre-vious sections that this will only declinethe farther away from the teacher achild sits. Indeed, typical classroom sig-nal-to-noise values are -7 to +5 dBoverall (see chart for the effect signal-to-noise has on speech recognition).

Yet normal-hearing children require at least +6dB S/N — how can weachieve this by altering the variablesof distance, noise, and reverberation?

We could increase the signal by having the teacher raise her voice —the common solution. Yet this onlyincreases teacher vocal fatigue andsick leave, and would require theteacher to speak at 94dB — the

noise level of an 18-wheel truck — to provide the +6dB S/N required at the back of the room.

We could reduce the noise and rever-beration in the classroom by addingacoustic treatments anddemanding that

the children be quiet, but this is an expensive or futile effort. Nor doesit address issues of distance.

A more effective method is to moveat-risk students closer to the teacher.This is only practical for a few stu-dents, however, and doesn’t allow for much movement by either theteacher or the student.

Overall, these situations are not veryencouraging. Is it worth the effort,then, to improve signal-to-noise ratio?Numerous studies show the answerto be an emphatic YES.

signal-to-noise

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There’s no getting around the impor-tance of good speech intelligibility inschools. Classrooms are clearly auditory-verbal environments — children spendas much as 45% of the school day in a listening situation. Language develop-ment occurs early in life, and what’smore, literacy is directly related to audi-tory development. Kids who have goodlistening experiences tend to becomebetter readers.

In addition, much of the material andvocabulary is new to students — they are,after all, just learning.

From an academic perspective, difficulty hearing and understandingleads to disruptive behavior.

Finally, there’s overwhelming empiri-cal evidence showing that improvedS/N results in better student atten-tion, comprehension, test scores, andon-task behavior.

Log on to www.phonicear.comto order reprints of these studies or go to the links where provided and download.

With the help of wireless technology, it’s actually possible to improve signal-to-noise ratio without seating restric-tions or costly modifications to classroom construction.

the importance of acoustics

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It’s called sound field, and it consistently provides:

• Compensation for the variables thatadversely affect signal-to-noise ratio

• The ability for any child anywhere in the room to hear the teacher as ifhe or she were only a few feet away

• A focus on the teacher — not background noise or echo

• 8 to 10 dB S/N ratio and up to 30% improved speech recognition

• Better test scores — often dramatically better

• Improved attention and behavior

• Reinforcement of language develop-ment and literacy in all students

the sound field solution

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In the same way that sitting close to the teacher results in a

positive signal-to-noiseratio and strong speech

discrimination, a wirelesssound field system

delivers a clear, intelli-gible speech

signal byreduc-ing key

distances.

First, the teacher wears a small wire-less transmitter with a microphoneplaced within 6in/11cm of his or hermouth (or connected from a receiverdirectly to a VCR, CD player, etc. for a surround sound kids love).

His or Her voice signal is transmit-ted across the room through radiowave or infrared light, bypassingthe effects of distance, noise, and reverberation.

The teacher’s voice signal is thenbrought close to students’ earsthrough speakers placed around the room.

Did you catch that? Sound field usesthe advantages of close proximity tothe sound source twice — first byplacing the microphone close to the teacher’s mouth where it picks upa strong signal nearly free from back-ground noise, and second by placingspeakers closer to the students. Ineffect, the teacher is never more than a few feet from students, and a gentleamplification brings the signal-to-noiseratio above the 6dB requirement.

Amplification allows teachers to speak in a normal voice and since it’s wireless,they can move freely around the roomor turn to face the chalkboard whileeffortlessly maintaining the level of hisor her voice.

how does it work?

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Since the 1970s over 50 studies have been conducted to find out justhow much difference sound field systems make.

In Florida from 1993-95, an extensivestudy on “Improving ClassroomAcoustics” was conducted among 2,054students in 94 kindergarten, first andsecond grade classrooms. Sound fieldwas installed in 64 classrooms, while 30classrooms acted as the control group.Some of the findings include:

• 96% of teacher agreed that attentiveness, listening, and comprehension improved

• 100% of school administrators agreedthat teachers enjoyed the systems

• 92% of administrators thought thatsound field enhanced class instructionand management

Other studies have found:

• Vocabulary test scores improved by 12% with sound field.

• Spelling test scores of 3rd, 4th, and5th graders have been shown toimprove by 14.5%, 9%, and 22.4%respectively when using amplification.

• Comparative results from projectMARRS (Mainstream AmplificationResource Room Study) indicatedthat students in an amplified class-room showed significant improve-ments in Scholastic ReadingAchievement scores.

What do audiologists and teach-ers have to say about sound field?

“Students in the classrooms with an FMsound field system achieved greater liter-acy gains than control students. Twice asmany students achieved up to sevenreading levels of literacy growth com-pared to the control students.”

Beata Darai, Aud, FAAA“Using Sound Field FM Systems to Improve Literacy Scores”Advance for Speech-Language Pathologists and Audiologists

“Numerous investigations have shownthat when sound field amplificationsystems are used, psychoeducationaland psycho-social improvementsoccur, academic gains were obtainedat a faster rate, to a higher level, andwith reduced cost.”

Carl Crandell and Joseph Smaldino“Room Acoustics for Listeners with Normal Hearing and HearingImpairment” Audiology: Treatment

“Before sound field only 44-48% of 1st grade pupils tested at the ‘basic’level and above. After seven months ofsound field 74% of children tested atthe ‘basic’ and above level. Studentsalso showed significant improvement in vocabulary, word-usage skills, andwere much more likely to answer questions appropriately.”

Linda Crozier, MA, CCC-SLPW. Russell Todd Elementary School, Roosevelt, Utah

does it really work?

For many more references visit www.phonicear.com

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There are several sound field systemoptions, each with its own specialadvantages and applications.

Our popular, portable, RADIUM

system let’s you choose from 16channels on both the receiverand transmitter—no preselectionof channels required. It sets upin minutes and is very afford-

able, making it a greatchoice for first time soundfield users. With two speak-ers housed in one unit,RADIUM can easily improvethe listening environment

in almost any classroom. Andbecause it’s battery powered and com-pletely portable, you can even use itfor outdoor events, physical education,assemblies and more! RADIUM also features two built-in channels for easy team teaching and a student pass around mic.

The new EASYLISTENER 2 transmits the teacher’s voice through four high-performance compact speakerspositioned around the class-room. While this requires moreinstallation than the RADIUM, theadvantage is OptiVoice, our exclu-sive speech clarity control. Designedfrom transmitter to speakers for

sound quality, speech clarity, and simplicity, this system lives up to itsname—EASYLISTENER 2. Easy to use—easy to hear the difference! A team-teaching option with a handheld mic is also available.

Unlike RADIUM and EASYLISTENER 2,which transmit sound using radio frequencies, VOCALIGHT uses infraredlight. The advantage is the ability to use an unlimited number of systems in the same building. Since infraredlight can’t penetrate walls, every class-room can use a VOCALIGHT. Ourinfrared technology is also immune to interference from ballast lighting orindirect sunlight. VOCALIGHT offers twobuilt-in channels for team teaching and a pass around mic.

Try any system for 45 days!

which system?

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portability yes no no no

quick installation yes no no no

cost

sound dispersion very good best best good

*ceilings must be at least three meters or higher than ten feet for distributed ceiling speakers;higher than 12 feet for cluster speakers. Four speakers are usually best for rooms approximately30x30 ft or 9.1x9.1 m or more.

$ $$• $ • $$ $ • $$ $ •

features RADIUM 4 compact spkrs 4 distributed* ceiling cluster*

These charts are provided as anoverall guide for system selection.Recommendations may varyaccording to room configurations.

features RADIUM EASYLISTENER 2 VOCALIGHT

technology FM FM infrared

frequencies 216MHz 216MHz 2.3/2.8 MHz

built-in channels 2 1 2

approximate installation time 5 minutes 60 minutes 90 minutes

relative cost

number of systems per install 8 -16 19+ no limit

aux input (CD, TV, computer etc.) 1 (4with aux box) 1(4with aux box) 1(4with aux box)

aux output 1 1 1(interfacing/rebroadcasting)

3-band equalizer no yes no

OptiVoice™ speech clarity control no yes no

speakers 2 in 1 column4 wall or ceiling, 4 wall or ceiling,

or 1 ceiling or 1 ceiling

team-teaching optionyes – with yes – with yes – with

handheld mic additional receiver/ handheld michandheld mic

receiver size66x14x10 cm 21.9x5.4x16.2 cm 22x21x5 cm

25.9x5.7x3.9 in 8.6x2.1x6.4 in 8.5x8.3x1.8 in

$ $$• • •$ $$ $ $$

which features?

which speakers?

$$

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collar mic available inFM or infrared. FM ver-sion has mute switch

which mic?features boom earhook IR lapel FM lapel collar

comfort good good excellent excellent good

feedback resistance

excellent very good fair fair fair

sound quality excellent good fair fair fair

earhook micboom mic

infrared lapel mic FM lapel mic(wear as shown or clip on)

lapel mics

collar mics

head-worn mics

infrared collar mic

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fundingEven after they recognize the benefitsof sound field, some schools andschool districts don’t feel they havemoney available — that’s where grants,funds, benevolent groups, and creativefund-raising can help.

There are numerous grants availablefrom government education programs,corporations, and nonprofit groupstotaling billions of dollars. In addition,some schools have been able toaccess funds through their technologybudget, while others have benefitedfrom fund raisers held by the localParent/Teacher Association, RotaryClub, or other benevolent groups.

The easiest way to begin is to visit www.phonicear.comand go to our funding guide where we have links to many grant and fund-raising sources.

If you don’t have access to a computer,call us at 800-227-0735 then press 5,and ask to receive our Funding andGrant Writing Packet, which lists manyways to obtain funding, the differencesbetween funding sources, and placesyou can call for more information.

Phonic Ear also offers a free 45-day evaluation so that you can expe-rience firsthand how sound field canbenefit both students and teachers.

Since we first began working withwireless systems in schools in 1968,Phonic Ear has been helping studentsin every situation, from preschoolthrough college.

We are headquartered in California’sSonoma wine country. Here, our 140employees – one-thirdof whom have beenwith us for at least 10years – design, build,improve, and sup-port the prod-ucts that

thousands of people in over 60 nationshave come to rely upon.

We are convinced that once you tryPhonic Ear products you’ll be as excitedas thousands of other educational pro-fessionals about the power of soundfield to capture students’ attention and achieve great improvement in comprehension.

Call our customer service departmentto answer product questions or set upa free 45 day trial.

USA: 800.227.0735, then press 5

Canada: 800.263.8700

Outside USA or Canada:707.769.1110

web: www.phonicear.com

©2004 Phonic Ear Inc. Phonic Ear and the names of Phonic Ear products are trademarks or registered trademarks of Phonic Ear Inc. in the U.S. and other countries 828-6880-113/Rev. A/4445 507

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