Microphone Installation
Make sure all mounts for microphones are secure and tight. Use rated materials wherever
possible. Try to maintain as much distance as possible from electrical equipment and fixtures,
without modifying the microphone placement guidelines. Be aware of large transformers, as
well as high voltage lighting instrument locations. These devices may still have an impact on
the performance of the microphones.
Most microphones can hang in place suspended by their own wire. Suspending a microphone
that is tied to a piece of 1/8” all-thread works very well for rigid applications and for judging
elevations at a particular location. All-thread is a common construction material and is available
with many accessories such as a sturdy beam clamp for attachment to existing steel. All-thread
comes in a variety of lengths and sizes.
The Constellation system requires a large number of Constellation microphones to be installed
using various methods depending on location and type of microphone being used. In all cases,
special attention is needed regarding the ground of the signal path attached to the microphone.
Pin-1 of the signal, otherwise known as Ground, should have only one path between the output
of the microphone and the ground terminal of the Constellation processor. If alternate ground
paths exist via wiring or connectors, increased noise, usually hum, will be added to the system
and will have to be corrected. Many times this involves re-installing cabling or providing insulation
to connectors to prevent connection to other grounds or conductors.
In an effort to prevent these kinds of installation faults, the following guidelines need to be
practiced:
■
Starting at the microphone, the metallic parts of the microphone capsule should not come
into contact with any conductive material. This will provide a connection of the signal
ground to the mechanical ground of the building or other ground path, which can induce
noise at the microphone input of the Constellation processor.
■
The metal shell of the XLR that is connected to the microphone is attached to signal ground.
Pin-1 of this connector is tied to the chassis of the connector. This XLR connector, and all
others, must be insulated so that they cannot come into contact with any other material
that could provide an alternate ground path, including other XLR connectors attached to
other microphones.
■
Combining of Pin-1 conductors at a terminal block is not permitted.
■
When using an input type XLR patch box to accept a number of individual microphone
inputs and combine them into one multi-core cable/snake, the box should be tested for
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CHAPTER 4: MICROPHONE LOCATIONS AND INSTALLATION
