Using wireless in-ear monitors for point-to-point
A wireless in-ear monitor system (IEM) can also be
used as a point-to-point system with only one modification
at the receiver. At the transmitter, no modification is
usually required since it is AC powered and can accept line
level signals directly. (See Figure 5-2.)
The modification to the receiver is again for AC
power. Many IEM receivers use 9-volt batteries and
thus can use a procedure similar to that for the 9-volt
transmitters above.
The only other accommodation necessary at the receiver
is adapting the stereo (TRS) mini-phone jack output to connect
to the destination audio system. This is effectively an
unbalanced, -10dBv signal, suitable for most line level input
devices. It is recommended that any receiver limiter be
switched off for point-to-point applications in order to obtain the
maximum drive level.
Once power and audio connections are made, the IEM
receiver should be secured to an elevated location to allow
best line of sight to the IEM transmitter. Again, weather
protection for the receiver can be provided by a ziplock bag or
similar covering.
A significant difference between IEM and wireless
microphones for this application is that the stereo IEM
can transmit two audio channels (multiplexed) per
radio frequency while the wireless microphone system
can transmit only one audio channel per radio
frequency. If stereo transmission is required IEM is
more cost- and spectrum- efficient.
Selection
and Operation
of Wireless Microphone Systems
52
CHAPTER 5
Application Notes
Figure 5-1: point-to-point using a wireless microphone system
Figure 5-2: point-to-point using an IEM system (with directional antennas for maximum range)