4 SAFETY
FIRST
It is important that loudspeaker systems are used in a safe manner.
Please take some time to review the following points concerning safe use
of EM Series loudspeakers.
Professional loudspeakers are capable of producing extremely high sound
levels and should be used with care. Hearing loss is cumulative and can
result from levels above 90dB if people are exposed for a long period.
Never stand close to loudspeakers driven at high level.
4.1
Rigging and suspension
WARNING: Suspending the system should only be done by qualified
personnel following safe rigging practices. Secure fixings to the
building structure are vital. Seek help from architects, structural
engineers or other specialists if in any doubt.
5 AMPLIFICATION
The EM15 and EM150 are designed to be used with professional power
amplifiers capable of producing the following power outputs into 4 ohms:
EM15 4 ohm
50-100W
EM15 16 ohm
200-400W
EM150
400-500W
Care should be taken to avoid amplifier clipping. It is important to
understand that a low power amplifier driven into clipping is more likely to
damage a loudspeaker than a higher power amplifier used within its ratings.
This is because music signals have a high peak-to-average "crest" factor.
When an amplifier is severely overdriven, its output waveform is clipped
(its peaks are squared off) – reducing the crest factor. In extreme cases,
the waveform can approach that of a square wave. An amplifier is normally
capable of producing far more power under these conditions than its
undistorted rated power output.
The use of very high power amplifiers with outputs greater than those
recommended is discouraged.
Care should be taken to avoid switch-on surges, which can result in
momentary power peaks in excess of specified ratings. When powering up
a sound system it is important to switch on the amplifiers after the mixer
and control electronics have stabilised. When powering down the system,
reverse the sequence and switch off the amplifiers first.
Martin Audio – EM SERIES
E
NGLISH
4
CONTENTS
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GUIDES
