The two cannot be compared, they are equally important. It would be like deciding whether to purchase the text books or fix the leaky roof. If the roof gets fixed, but the students don't have any books to learn from, the school does not serve its purpose. Sound enhancement systems are a valuable necessary educational tool not a facility improvement and hearing is not a luxury. Unlike money that is spent on facility renovations and repairs, this is an investment that has a significant opportunity for a financial return in the form of savings in special education reductions and reduced substitute pay for absent teachers.

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Absolutely yes! There are a few flaws (some technical) with the loud voice theory. First our voices are not meant to be projected loudly for seven hours a day, five days a week. This is why teachers are 32 times more likely to suffer vocal problems than any other occupation; not to mention just exhaustion, fatigue, and burn-out. Secondly, the energy of speech is carried 90% by the low frequencies yet only 10% of the intelligibility of speech resides there. Intelligibility is carried by the weak high frequency sounds. Thus a loud voice powers the vowels, but obscures the consonants. It is counterproductive. Third, even a loud voice falls by 6dB for every doubling of distance and given the current acoustical conditions the backrow still loses 45% of speech intelligibility.

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Yes. A study done in Colorado on children who had previously performed in the 8th and 9th stanines increased their test scores by 3.64% after using sound enhancement systems. This is statistically significant given the fact that they were already "high-achievers" and did not have a lot of room for test score improvement. It proves that even those who appear to be achieving, may not be achieving their full potential because they too are either not hearing ALL of the information and/or are using up excess energy on listening that could be used for additional learning.

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Yes, they are highly recommended. Research proves they encourage student participation, sharing, and allows ALL of the students to hear each other; thus engaging in passive learning.

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Yes. Enhancement of the speech signal is highly desirable since the speech-to-noise ratios are often poorer than closed classrooms, for two reasons: The background noise levels are predictably higher, and the teachers often use softer than average voice levels in order to reduce interference with the teachers in adjacent classrooms. However, it is more challenging in that placement of the speakers is critical and teachers may need to coordinate schedules and alternate use of the system to avoid interference. If the volume is properly set and regulated, it is feasible.

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Absolutely not. The ANSI (American National Standards Institute) Standards regarding classroom acoustics completely ignore critical factors contributing to poor SNRs (Signal-to-Noise Ratio) which negatively affects every child's ability to hear in almost every "real world" classroom. See the Poor Acoustics page for more details on SNR.

ANSI Standard Scope of Practice

1.1.2 acoustical performance criteria are specified in this standard by limits on maximum one-hour a-weighted and c-weighted background noise levels and limits on maximum reverberation times. An objective of these performance criteria is to achieve a level of speech that is sufficiently high relative to the background noise level for listeners throughout the classroom or learning space. However, a requirement for the relative difference between speech levels and levels of background noise, usually referred to as the signal-to-noise ratio, is not within the scope of this standard.

1.1.4 this standard does not apply to noise generated within a classroom by its occupants. Occupant- generated noise sources include voices and the sounds of classroom activities such as the moving of chairs. Furthermore, this standard does not apply to the noise from portable or permanent built-in equipment used during the course of instruction, such as audiovisual equipment and computers. However, the background noise generated by occupants and instructional equipment can seriously degrade communication or speech intelligibility in learning spaces.

Why does ANSI exclude SNR from the scope of its standards?

• Even the best acoustical environment cannot correct the problem of the teacher's voice dropping over distance. The signal (teacher's voice) drops 6 decibels for every doubling of distance. See diagram

• Acoustical modifications are also unable to address the level of background noise generated by students, electronics, and other instructional equipment in every "real world" classroom which is why their standards must be based on an UNOCCUPIED classroom.

• ONLY a SES with speakers evenly distributing the sound can ensure that ALL children in ALL areas of the classroom will hear the teacher's voice at the recommended SNR of +15 decibels.

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No. Teachers do NOT need to wear a second microphone in these instances. Teachers simply wear the microphone for the classroom SES and the transmitter/microphone for the personal system is connected to the classroom SES receiver. Many classroom SES models are able to interface with ANY of the personal FM systems on the market, but be sure to confirm this with vendors if such an option is important for your implementation. This may be important if existing service contracts for personal FM systems need to be honored. There is also an added benefit for students using personal FM systems in an SES equipped classroom. These students currently "miss out" on passive learning that takes places from discussions/contributions of other students in the classroom and from sound generated from other media sources in the room. A personal system alone only allows the hard of hearing child to hear the teacher. Most quality classroom sound enhancement systems include a handheld student pass-around microphone that allows the hard of hearing child to hear the other students and multimedia equipment if that too is connected to the SES.

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No. Good acoustics are important at every level of education in order to maximize auditory learning. While older children may have a more developed auditory neurological network and be less prone to ear infections, there are other considerations that warrant improved classroom acoustics through use of sound enhancement systems. Middle school, high school, and college students are required to rely more on their own note taking abilities and less on “handouts” from teachers. Therefore, they need to be able to clearly hear and understand what their teacher is saying in order to properly learn and record that information. Also, older students are more prone to hearing loss generated from overexposure to high levels of noise. Approximately 3% of children in grades 1-3 have a high pitch hearing loss which is attributable to damage from excess noise. In comparison, 30% of college freshman and 60.7% of college sophomores have significant high pitch hearing losses. Students with noise induced hearing loss are at high risk form speech intelligibility problems in typical noisy and reverberant classrooms. (Lipscomb, D.M., “The Increase in Prevalence of High Frequency Hearing Impairment Among College Students,” Audiology, 1972, Vol. 11, pp. 231-237.)

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