AV Design Reference Manual - InfoComm

Chapter 18: Venues
Sound Systems, continued
Auditory Assistance Systems
Auditory assistance systems, also known as hearing-impaired or assisted listening systems, are
often required in venues large enough to need a sound reinforcement system. These systems
can be:
• Infrared (IR) based.
• Radio frequency (RF) based.
Both have advantages and disadvantages that need to be considered.
IR-based systems provide better security because the transmitter and receiver require line of
sight (LoS), and the signal does not pass through walls. The disadvantage is that they require
LoS to function and they are susceptible to sunlight, which also contains IR.
RF-based systems do not depend on LoS and are less secure because RF travels beyond the
confines of the room and can suffer interference from external sources.
Houses of worship can present even the most seasoned audio system designer with difficult
challenges. Acoustically, due to the reverberant nature of the finishes typically chosen,
providing good speech intelligibility, which is a primary need, is not an easy task.
When both speech intelligibility and accurate music reproduction are required, the challenge
becomes that much more difficult, but with careful planning, loudspeaker placement, and
microphone pick up patterns, the obstacles can be overcome. This will allow for the
implementation of a good quality, high performance, and stable system.
© 2006 BICSI ® /InfoComm International ® 18-19 AVDRM, 1st edition