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Field Adjustments

APS microphones and speakers

Engineering drawings
Engineering drawings and specifications should include location and orientation of all microphone and speaker components. The following section illustrates some good and poor placement of pushbutton-integrated and pedhead-mounted speakers.

Microphone location
Some APS require installation of microphones to monitor the ambient sound; this is part of the automatic sound adjustment feature.

The microphones are measuring the sound levels to adjust the volume at the waiting location. If the microphone is mounted too far from the intersection, it will not adequately sample and adjust the volume levels. The WALK indication is likely to be too quiet for a pedestrian who is waiting at the curb, prepared to cross, to hear above the sound of traffic.

APS speakers
Speakers for APS may be pedhead mounted or pushbutton-integrated. There are different issues to be considered, depending on the speaker location. Separate drawings are provided to indicate locations of pushbutton integrated speakers and pedhead mounted speakers.

Some manufacturers also provide options to have a speaker at the pedhead in addition to a speaker at the pushbutton location.


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