Simplified Classroom Audio Guide
Improving the volume, clarity,  and dispersion of a teacher’s voice makes sense!
If a child can hear the teacher clearly, it is more likely that the child will understand what the teacher is saying.

We need to capture, receive, amplify and disperse the teacher’s voice.

Capture: Microphones. They can be wired or wireless. 
Wired microphones limit a teacher's movement around the classroom.
Handheld microphones are fine for singers, but teachers need their hands. A wireless microphone is more practical. Wireless units transmit (rf) radio signals or (ir) infrared signals to a tuned receiver. Wireless microphones can be worn on the lapel, over the head, as a headset or around the neck as a pendant. 
Lapel and headset types need to be connected to a belt pack transmitter, the pendant type and some athletic headsets are complete microphone and transmitter units.

Wireless Receiver:  A sensor that converts the microphone signals to an electrical sound wave signal.
Infrared receivers need a wide field of view and must be centrally mounted, preferably on a ceiling. 
Radio frequency receivers utilize antennae and can be out of sight, mounted directly on or near the amplifier. Radio signals penetrate walls and may interfere with other devices that monitor similar frequencies. This interference is minimized by using high frequency ranges (2.4GHZ) that are not in wide use.

Dispersion: Speakers
The number, size and placement of speakers are the most critical components of any classroom audio system. Speakers need to be matched to the amplifier and should be mounted as high as possible above the floor.

The acoustics of each room is important. Sound reflects off of floors and walls, the returned sound waves produced can interfere with or feedback into the microphone. Test different speaker placements for the best results.
Just listen, you'll know.

    Minimum: One centrally mounted or two wall or shelf mounted speakers placed on opposite corners facing the students, or in the rear corners of the room aimed toward the center of the room.

    Better: Four speakers are better than two. Each setup is different, depending upon the size and shape of the room.

    BEST! Four to six, evenly spaced, ceiling mounted speakers. These usually are aimed straight down, however, some ceiling speakers can be aimed for better coverage. This setup provides an even dispersion of voice and music at a lower volume. The room literally fills with sound.

    COST! A small desktop PA or Stereo 2 speaker setup should cost between $70.00 - $400.00
A fully installed ceiling system, will cost from $2,000 to $4,000 for each room. 
A do it yourself setup is under $1000.00.

Assisted Technology:  Individual student wireless headsets are available and can be incorporated into any class environment. They provide amplified audio to individual students.

Portable Classroom Audio Solutions: