This project born to create an extreme subwoofer without a budget limit to add without problems to any hi-end audio systems.
In most cases you will only need one subwoofer although someone prefer a symmetrical configuration in a pure audio systems.
As we know it is difficult to locate the subwoofer then in a medium sized room if we place this subwoofer between the speakers we lose nothing of the music track.
Of course we're talking about a subwoofer to be used only in the very low frequencies range below 100 Hz  so to be inserted in systems with 5" - 6" mid-woofer.

WOOFER

Eminence LAB15 Professional Series complete datasheet box guide To get the best transient response the my choice is a sealed enclosure in a large box with a Qtc near to 0.5. The DSP included in the plate amplifier will compensate the extreme low frequency band. Subwoofer Speaker Design by John Conover Subwoofer group delay by Dan Wiggins sealed vs ported-enclosures

AMPLIFIER

Wyntek electronic WAM-300 with DSP

In a domestic environment, it is quite easy to be able to reduce reflections at the medium-high range frequencies (see my project Passive Room Correction).
It is much more difficult to operate in the low frequencies range so this project uses a very special plate amplifier that integrates a DSP for digital equalization.
There are very few subwoofer amplifiers using an internal DSP and the WAM300 is probably the only one who can be connected in USB to a PC with Windows in order to change the all the parameters in real time while listening.
The DSP functions allows a perfect adjustment of the low frequency band and some setting can be changed also by a remote command.
The program works very well on Windows PC but in the CD included in the package there is also a version for MAC (still not tested).
Below I have a graph that shows the range of changes that can be achieved with the equalizer and various filters.

• WAM-300 manual and specifications

BOX