Planning The Installation - Locating Induction Loops - I-AMP GPT 60-IV User Manual

from damage, and compressors which reduce the dynamic range of the input program, increasing the
clarity for many hearing impaired.
A compressor is used to reduce an audio signal's dynamic range. The dynamic range is determined by the
following equation:
Dynamic range = ---------------------------
Typically humans can detect (hear) sound over a 140dB dynamic range. Most electronic equipment cannot
directly process this dynamic range without running into the electronic "noise floor" of the electronics itself.
Typically electronic systems can produce around 90dB dynamic range. Even this reduced dynamic range can
cause problems with the hearing impaired and should be reduced to 45dB or less. This can be achieved with
a 2:1 compression ratio dynamics processor.

Planning the installation - Locating Induction Loops.

Perimeter Loops:
Generally simple perimeter induction loop systems require the routing of the induction loop cable around
the outside of the required pick-up area. This area can be rectangular, square, or circular. The closer two
sides are, in a rectangular layout, the lower the induction loop power amplifier drive current required.
The induction loop may be placed at floor level or above. The loop may be routed around small obstacles in
the pick-up area (such as doors and window, etc.) without significant changes to the generated magnetic
field.
Figure-8 Loops:
The induction loop coverage area may be extended with the use of "Figure-8" cable layout. This
arrangement effectively increases the area that a single induction loop power amplifier can cover by a factor
of 2. Note that the length of the induction loop cable will increase and the induction loop cable cross
sectional area may need to be increased to allow for a maximum DC loop resistance of 1.8Ω.
INDUCTION LOOP AMPLIFIER
-AMP
G p t 6 0 - I v
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