The first four photo's below show a subwoofer for hifi and home-cinema use with two 18-inch woofers, one mounted on each side of the cabinet. The woofers work in a so called impulse compensated configuration. Big drivers are capable of moving huge amounts of air however, at the same time the mechanical forces involved can cause unwanted side effects. These two woofers work back-to-back so the opposite forces compensate each other and unwanted vibrations are cancelled. The heavily braced cabinet is made from 18mm thick / 13 layer and 40mm thick / 28 layer Marine Grade Baltic Birch plywood, epoxy coated and then finished with sveral coats of semi-gloss deep black spray-paint. The total weight is 140 kg's and the drivers are powered by an efficient 500 watt BASH plate amplifier with parametric EQ. Bandwidth +/-1dB is 14Hz to 37Hz with a usable bandwidth of -3dB from 13,2Hz to 39Hz or -6dB from 12,4Hz to 42Hz. The measurement (range 10Hz to 500Hz) shows some background noise at higher frequencies but that is because the microphone was placed in my listening seat at 3 metres distance from the subwoofer. Notice the cd for size reference!

The following is an example of a three-way loudspeaker system built to the client's specifications (shape, size and driver configuration) with two 7-inch Nomex Kevlar woofers per side, a 5-inch ceramic midrange and a 3/4-inch ceramic tweeter. The heavily braced cabinets are made from a combination of 18mm and 30mm thick Marine Grade Baltic Birch plywood with an extra top layer of book-matched birch veneer. This system is a completely active set-up with DEQX digital crossovers and room correction, all driven by no less than six Pass Laboratories monoblock amplifiers. The details show some of the the CNC-machined internal bracing elements from which the cabinets are assembled and the rear of one of the loudspeakers with multiple Furutech binding-posts and Furutech internal wiring to connect the individual amplifiers to.