A microphone is perhaps the most important link in an audio chain.

As the connection between the sound source and the sound system, it must interact efficiently with both.

Choosing this link successfully requires knowledge of the sound source, the sound system (including the room acoustics), microphones and the actual application.

A number of microphones are available from SigNET for use with its induction loop systems (see our Microphone Selection Guide below).

Microphone Selection Guide

The most common microphones used in induction loop systems are 'electret' lecturn, handheld, boundary and lavalier microphones as they have the highest tolerance of magnetic feedback. Best practice (though not always possible) is to place the microphone(s) as close as possible to the speaker.

Dynamic microphones should not be used as they contain moving coil magnets which can be affected by the magnetic field generated by the loop.

A method that is sometimes suggested for overhead placement is a ceiling-mounted boundary microphone. This should be used with caution as (a) microphone too far from the desired sound source, especially in the case of a high ceiling and (b) the ceiling in buildings of modern construction is often an extremely noisy location due to air handling noise, lighting fixtures and building vibration.

Phantom power is provided on all PDA amplifiers so electret microphones with batteries are not necessary.

Conference table application (centre of tabletop, counter, etc)
AMT tie/desk mic
APM plated mic
MH handheld mic + G121 stand

Lectern application (for pulpits, lectures, etc)
AML fixed gooseneck mic, long stem
AMLS fixed gooseneck mic, short stem
AMD movable gooseneck mic, long stem
AMDS movable gooseneck mic, short stem

Lavalier application (e.g. for the lapel of an after dinner speaker)
AMT tie/desk mic
AMR/LA (radio mic) – 4 selectable frequencies

Ceiling application (recessed in the ceiling above a table)
APM at distances of 3 metres
PRO45 at distances 12 metres

Desk Microphone with Push To Talk (PTT) application
AMD/P (as AMD with PTT)

Handheld application
AMH handheld mic AMP professional handheld mic (connection lead required – contact our sales desk for advice)
AMR/HA (radio mic) – 4 selectable frequencies

To avoid interference, microphone cables should be sited at least one metre away from loop cable.

If in doubt about which microphone to use, please contact our technical department for advice.


Specific References