Posted by Adrian Mack [ 203.190.195.199 ] on April 27, 2005 at 22:30:24:

In Reply to: Re: Questions on sub-woofer amps posted by gumby1 on April 07, 2005 at 00:15:16:

Its there to artificially boost the low end response. Especially for sealed box subwoofers.

If its the typical PE/Apex/Stryke style plate amp, it uses an EC SK 2nd order HP filter. Essentially its a high-Q 2nd order highpass filter. When Q>1.0 it forms a filter peak which is what forms the "bass boost", or EQ. Modifying it is a matter of replacing two resistors on the preamp board, and using simple textbook formula's to choose any Q and Fc you want.

It is possible to design a subwoofer which EQ is an integral part of the design to form flat response, but EQ used disappropriately always makes a bad result.

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