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Field Adjustments

Installation of speakers and microphones

Confirming speaker location and orientation
Speaker location and orientation need to be checked against the specifications. Installers should make no change in speaker location or orientation without checking with the responsible signal engineer.

Poorly located speakers can result in:
  • Ambiguous information about which crosswalk has the WALK interval;
  • Failure of blind pedestrians to begin or end crossings within the crosswalk; and
  • Veering of blind pedestrians outside the crosswalk, possibly into conflicting traffic.
See discussion and examples in Installation Specifications for more information.

Speaker location
Incorrect speaker location can make a difference in ability of pedestrians who are visually impaired or blind to discern which APS is sounding.
  • Each APS speaker at a corner must always be closest to the crosswalk it signals.
  • For pedhead-mounted APS, speakers should not be automatically located on the pedhead that signals the same crosswalk. The pedhead closest to one crosswalk may signal the perpendicular crosswalk. In this case, speakers must be mounted on the pedhead for the perpendicular crosswalk. See discussion and examples on the Pedhead-mounted speakers page.
Speaker orientation
The speakers should be adjusted so the pushbutton locator tone can be heard by a pedestrian approaching the corner from both the sidewalk side and the street. However, it is most critical that the APS WALK indication can be heard at the beginning of the crosswalk.

Specifications for installations should include speaker orientation. See discussion in Installation Specifications.

Precise orientation of the APS speaker is especially critical at locations with audible beaconing. If a speaker or transmitter is oriented even a few degrees out of alignment with the associated crosswalk, pedestrians may inadvertently travel out of the crosswalk, perhaps into the path of vehicular traffic.


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