Martin Audio Amplification, Safety First, Cable Lengths, Martin Audio - CS265, English, ohms

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3 AMPLIFICATION

The CS265 is designed to be used with professional power amplifiers capable of producing 100-200W per channel into 4 ohms:

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.

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 Contractor 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.

5 CABLE LENGTHS

When connecting loudspeaker systems to an amplifier, it is recommended that the return resistance of the cable used is less than one tenth of the nominal impedance of the system or systems in parallel. The table below gives an indication of the maximum permissible cable runs for various conductor cross-sectional areas.

Conductor CSA		Maximum Cable Run
	4 ohms	8 ohms	16 ohms
1.0mm2	11m	22m	44m
1.5mm2	17m	34m	68m
2.0mm2	22m	44m	88m
2.5mm2	29m	58m	116m
4.0mm2	44m	88m	176m
6.0mm2	66m	132m	264m

All material © 2007. Martin Audio Ltd. Subject to change without notice. 3

Martin Audio – CS265

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