9 . 4 U n p o w e r e d L o u d s p e a k e r s - L i m i t e r s
CAUTION: The assumptions that must be made about how to set a limiter and what a driver's power handling limits are cannot address all conditions of use. As such, limiters cannot provide absolute protection nor provide any guarantee against damage or failure from excessive inputs. At best, they can only provide some degree of protection.
9 . 4 . 1 L i m i t e r s A n d L i m i t i n g
Limiters can help avoid either of two things, depending on the signal frequency content and the amplifier / driver power ratings. The choice depends on which will be exceeded first.
Exceeding a Loudspeaker's Thermal Limit:
The limiter is used to prevent the amplifier, operating within its capabilities, from exceeding the loudspeaker's capabilities.
Exceeding the Amplifier's Output Limit (Clipping).
The limiter is used to prevent the amplifier from exceeding its capabilities, even though the loudspeaker is operating within its capabilities.
9 . 4 . 2 M X 8 7 5 0 L i m i t e r D e s i g n
EAW has done the work of determining the MX8750's limiter characteristics with real audio signals by performing a number of tests on its behavior with real audio signals and analyzing how this relates to both loudspeaker power handling limits and sonic performance. Based on measurement and analysis of the above variables, EAW Engineering was able to formulate a set of "rules" for setting MX8750 limiters. Listening tests determined settings that maintain good sound quality while maximizing protection. These rules are incorporated into the MX8750 Output Limiter Wizard. See Section 9.4.3.
Because limiters differ in their behaviors from manufacturer to manufacturer, EAW can only provide limiter settings for its own MX Series of processors. These are the only ones on which the required analysis was done to optimize settings. As such, EAW limiter thresholds are only valid for use with an EAW MX8750 digital processor and with amplifiers that have or are set to 32 dB gain for all passbands. This assumes that the factory gain settings for the processor outputs are also used. For amplifiers with gain other than 32 dB and for loudspeakers where no factory limiter settings exist, use the MX8750 Output Limiter Wizard to determine the correct limiter threshold settings. See Section 9.4.3.
9 . 4 . 3 M X 8 7 5 0 O u t p u t L i m i t e r W i z a r d
The MX8750 Output Limiter Wizard is an
Apply the settings determined from the Wizard to the MX8750 using the MXWare control program.
NOTE: The Wizard's settings apply only to the MX8750. They should not be applied to other limiters for the reasons stated above.
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