Classroom Amplification Makes an Academic Difference

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					Classroom Amplification Makes
    an Academic Difference
         James C. Blair, Ph.D.
         Utah State University
Academic Findings
 Ray, Sarff, and Glassford, 1984
   Amplifying a classroom helped children score
    higher on academic achievement tests
 Gertel, McCarthy, and Schoff, 2004
   Amplifying a district helped children improve
    their academic achievement test scores by as
    much as one grade in one year
   Especially helped the Title I students and ESL
    students
How Important is
Listening?
 Two-thirds of a student’s day
  consists of listening to and
  participating in spoken
  communication
 Listening environments need to be
  free of acoustic and non-acoustic
  barriers
Other Findings
 Teacher absences due to loss of voice or
  fatigue is reduced
 Student’s interest in and attention to
  teacher improved
 Behavior problems are reduced
 Fewer questions asked that are for
  clarification purposes
 Increased student participation in class
  when a pass-around microphone is used
The Problem
 As talker moves away from the listener the
  signal decreases 6dB every time the distance is
  doubled (distance is a problem)
    Start at 65dB HL, 6” from mouth, at 1 foot the
     intensity is 59dB, at 2 feet the intensity is 53dB, at 4
     feet 47dB, at 8 feet 42 dB, and at 16 feet it is 36dB
 Noise is a problem
    A normal listener at the back of the room, if it was
     very quiet, would have a signal-to-noise ratio of +1, if
     no children were in the class.
    With children the background noise is going to be at
     least 45dB, or about -3dB
A second problem is
reverberation
 Reverberation occurs when sound
  encounters a hard wall
   Sound bounces around a room
   The effect of reverberation is slurring of
    speech as you move away from the talker
   Normal listeners do best when reverberation
    times are below .6 seconds
The Overall Problem
 When noise, distance, and reverberation are
  combined the result is speech is difficult to
  understand
    For normal listeners a +6dB signal-to-noise ratio leads
     to a 9% decrement in speech recognition
    When a reverberation time of .7seconds is combined
     with a signal-to-noise ratio of +6dB word recognition
     scores decrease by as much as 20%
    A student at the back of the room has a huge
     disadvantage
So Why Don’t We Complain
 It’s always been this way
 We figure out strategies
     We   get notes from the teacher/presenter
     We   read the text or the references
     We   talk to our friends about what was discussed
     We   sit close to the front of the room
 We would never allow children to be taught
  in a dark room, but we will allow them to
  be taught in a room in which they can not
  hear well
Study
 Five different classrooms used in the study.
    All were similar in size
        30 to 35 feet deep
        32 to 40 feet wide
    All met ANSI standard for noise and reverberation
        RT 60 .32
        Noise Criteria 32 dB
    Four teachers used classroom amplification, one did
     not
    A pass-around microphone was used in one classroom
     regularly, but either sporadically or not at all in the
     other three classrooms
Procedures
 A measuring microphone was placed on a
  tripod, positioned at the level of the child’s ear
  (placed near a child’s ear)
 Measurements were made at 9 different
  locations in each room (back center, left back,
  right back, left center, middle center, right
  center, front right, front left, front center)
 Measurements were made in 10 minute
  increments
 The Time, Energy, Frequency (TEF) system was
  used to obtain measurements
Signal-to-noise ratios with
infrared classroom amplification
 Obtained signal-to-noise ratios were on
  average between +13 to +20 dBA at
  every position measured in the rooms
 One classroom was not fit with a
  classroom system and all other teachers
  were asked to turn off their systems for 5
  minutes during the data collection.
   The average signal-to-noise ratios were
    between +2 and +6 dBA without
    amplification
Actual Conditions
(unamplified)
 Teacher asked children to read in a
  random order around the classroom.
   Average sound level at the microphone based
    on distance away from the microphone.
        2 feet - 59dB
        3 feet - 56 dB
        6 feet - 55 dB
        12 feet - 46 dB
   There are times when the sound level is 13
    dB less intense than at other times.
Results: Unamplified
Classroom
 Teacher’s measured vocal intensity;
   Front of the room at nearest student’s desk
    was 58 dBA, with a range of 50 to 65 dB
   Middle of the room at child’s desk, the level
    was 52 dB, again with a range of 40 to 60 dB
   At the most distant point, this is measured as
    being 18 feet from the most common place
    from which the teacher presents information,
    was 48 dB with a range of 40 to 52 dB
Implications
 The results indicate that at the front of
  the room the average signal-to-noise
  ratio was +15 with a range between +8
  and +20
 In the middle of the room the S/N ratio
  was 8 dB with a range between +1 and
  +10
 At the back of the room the S/N ratio
  was 0 dB with a range of -15 to +6 dB
Implications (continued)
 Depending on where the child is seated at any
  given time changes the amount and quality of
  input available
    There are times when everything is audible and other
     times when information is not audible at all
    At best the input to children is variable
 The child who has any kind of hearing problem
  is getting at best variable auditory input (about
  10% of the students)
 Remember this room meets ANSI standards
Amplified Classrooms
 In these classrooms all speakers were in the
  ceiling, providing direct sound to most of the
  children.
 No matter where the child was seated in the
  room they were getting no less than a +10
  signal-to-noise advantage.
 When the hand-held microphone was used the
  same advantage was present for the children as
  for the teacher, when not used it was like the
  results in an unamplified room.
Results (continued)
 Observations:
   In the classroom with no amplification
      Many students did not listen well when the
       teacher was talking
      After the teacher explained an assignment on a
       poem and the children started to work, the
       teacher noticed one child looking around as if
       trying to discover what to do. When the teacher
       asked if she had started to look at the poem, the
       student said, “Oh, I thought you were talking
       about some kind of foam and I didn’t know what
       you wanted us to do.”
      Little differences can make for a great deal of
       confusion
Logan City School District
 Few classrooms have used systems for many
  years
 Middle School was convinced that a system for
  their school was important
    Opted not to repave a parking lot and used the money
     to purchase audio enhancement for all instructional
     classrooms
 Legislature provided money for technology
    Superintendent and Board decided to use the bulk of
     the money to put audio enhancement in every
     classroom in the district
Current Findings in Logan
City Schools
 Three-hundred five teachers (K-12) were
  surveyed
 One-hundred sixty-five responded (54%)
 Questions and answers:
    Do you have classroom amplification in your room?
       93.9% yes; 6.1% no
    Do you personally use the equipment?
       89.6% yes; 10.4% no
    How often do you use the equipment?
         All day, every day: 48.2%
         When presenting information: 28.4%
         Occasionally, for special presentations: 10.6%
         When I think about it: 5.7%
         Other: 7.1% (don’t use it when there are groups in the
          class)
 Findings (continued)
 Do students use the microphone?
    Yes, 59.1%
    No, 40.9%
 How often and under what conditions?
    Pass the microphone around during class discussions:
     3.3%
    Use the microphone when presenting in front of the class:
     68.5%
    They use the microphone whenever they are talking to
     the whole class: 17.4%
 Do guests in the classroom use the system?
    Yes: 62.3%; No: 37.7%
 How often and under what conditions?
    When reading a story to the children: 29.5%
    When presenting information to children formally: 61.1%
    Whenever a guest talks they use the system: 61.1%
 Findings (continued)
 What is your impression of the system?
    I believe students are more attentive: 80.1%
    I can control classroom behavior more effectively: 65.2%
    It helps children in my class perform better: 53.9%
    The children like it when I use the system: 65.2%
    Because I don’t need to talk loud, or yell, I am less tired
     at the end of the day: 66.0%
    I don’t think that the system helps at all: 5.7%
 How important do you think an amplification
  system is in a classroom?
      Detrimental: 0%
      Not too useful: 8.6%
      Useful: 13.2%
      Quite useful: 11.8%
      Very useful: 35.5%
      Essential: 30.9%
    How to make it better
   Put it in the gym: 2
   Need hand-held mic: 19
   Cuts out all the time: 2
   Mic too heavy: 18
   Need smaller mic: 15
   Needs to connect to all systems: 13
   Mic Reverberates/Feedback: 6
   Too soft: 2
   Dead places in the room: 1
   Too loud: 1
   I have a loud voice, don’t need it: 2
   I wear it for hard of hearing child: 2
   We need complete technology classrooms: 2
How can we make it better?
(continued)
 We need someone to maintain it and
  teach about it: 3
 I love it: 6
 It is wonderful: 3
 Amazing: 1
 Nothing: 2
Some Considerations
 Installation of classroom amplification follows no
  systematic procedure.
    In most states they are installed by the companies
    They are fit subjectively
    We are finding considerable variability across
     classrooms and we have had to retrofit a number
    Many teachers will not wear the systems
         Too loud
         I speak loudly already
         Does not work well
         Unwieldy
         I rarely teach the whole class at one time
         What to do when it does not work well
         I forget to put it on
         Microphone is too heavy and gives me a headache
Unresolved issues
 We know that anything is better than
  nothing (unless it is not loud enough to
  make a difference)
 We don’t know what is truly feasible in a
  classroom (research says +15)
   Comfort
   Feedback
   Overflow
 We are not sure what is usual (study in
  process says we are at about +8)
Student’s Opinions (N=258)
 It is easier to hear the teacher
 It is easier to listen when the teacher is talking
 “I like it when the teacher uses the system”
 “I feel that what I have to say is important”
 “I feel listened to when I can use the
  microphone.”
 Where it is used, all student respondents had
  only positive comments to make about the use
  of sound enhancement
Teachers’ Opinions (4 large
school districts)
 Students are more attentive
 Teachers can project their voices more easily
 Teachers feel less fatigued at the end of the day
  (no need to talk loud or yell)
 Teachers experience less vocal strain
 Teachers report that students like it when they
  use the system
 Teachers believe that students achieve at a higher
  level
 Of all the equipment in the schools audio
  enhancement is ranked as first or second as ”the
  piece of equipment that has the greatest direct
  influence on learning”
Does it matter where the
speakers are located?
 Choices:
      Speaker in the front of the room
      Speakers on the walls
      Speakers in a cluster
      Speakers in the ceiling
 Any speaker is better than none
    Provided they are turned up loud enough to improve the
     signal-to-noise ratio
    The best placement is in the ceiling so as to be over the
     head of the children.
         This arrangement provides the most consistent sound to
          every child in the room.
         Other arrangements provide variable intensity as the child
          is moved away from the speaker
Classroom Amplification Makes
an academic difference
 It reduces or eliminates the effects of
  noise, distance, and reverberation
 All students can hear the teacher and
  each other all the time
 If we are able to communicate, we are
  more able to learn
 We need to do all we can to make certain
  that every child has a maximum
  opportunity to hear
Questions???

				
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posted:9/16/2012
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