To avoid air leakage, thus reducing the loss of sound pressure, Steve went around the steering column with fiberglass mat to seal it to the steel shaft. He then cut a hole the diameter of the column in a piece of wood, and slid it over the steering column and into place. A resin soaked mat and a rubber boot were applied to further ensure the seal. The gas and brake were done in much the same way. "The van is still totally driveable, but I wouldn't drive it for more than 20 feet and in a straight line," Steve says with a smile
Door seals are not as extreme as you might find with some competitors, but fall in line with the standard set by the rest of the install. The van's window seals were all replaced with new rubber; and the factory latch still opens and closes the door. But, from the outside, Destaco clamps securely lock the door down and make sure no air enters or escapes.
Electrical power for the system starts with three Stinger 200 amp alternators. Brackets had to be custom made to hold all three around the transversely mounted motor. They're all controlled by regulators set at a charge voltage of 17.5 volts. That's over three volts more than the system in a typical car.
Steve needs 17.5 volts because he is using eight 8-volt batteries wired in series to create a 16-volt battery system. Why? Because the Crossfire BMF1000D amplifiers he is using make substantially more power when the voltage is increased. Rules prohibit anything more than 18 volts, but that is probably beyond the threshold of the amplifiers capabilities.
Just aft of the sub enclosure is where all this high voltage resides. To get there, six snakes of 1/0 power wire are fed from the alternators to batteries. The batteries are connected with custom-routered copper buss bars. With each pair of batteries wired in series for 16 volts, the buss bars extend towards the front and up the back of the sub box. Here a terminal holds down a short, 1-foot piece of 4-gauge power cable to each amp.
The runs are kept short intentionally to make sure each of the 16 BMF1000D amps has a minimal voltage loss. The powerful Crossfire class D amps are configured in a bridged mode that allows a pair of them to be used as one. Each pair of these amplifiers drives one voice coil on each of the four dual 2-ohm, 15-inch subs. Steve estimates the current configuration scorches with nearly 20,000 watts of total power.
So the big question is, what kind of subs can take that kind of abuse? Digital Designs. DD is headquartered in Oklahoma City, Oklahoma and has been producing top notch subs since 1986. Known mostly in the Pro Audio market, their subs have always been available to anyone who wanted to abuse them. Serious SPL is now one of the company's biggest markets thanks their work with Steve and extreme aficionados like him.
The way the DD subs are mounted inside the van is rather peculiar. "People always come up to the van, take a look inside and say, 'Man, that'll never work.' That makes me really happy," says a smiling Steve. Looking at it myself, I understand where these questions come from, but how Steve came up with the design is difficult to understand. "I've spent so much time experimenting with things - it's crazy. I like to just go into my shop at night and go into the zone. I forget about time and the phone and eating - I just try things," explains Steve.
Inside the van, the box no longer has a front. It's basically a 5-sided enclosure. The best way to describe it is to imagine taking an oil drum and cutting it in half. You then mount the woofer on the top. Do this four times and arrange the subs two high and two across. Weld them together where the frames touch and you have Steve's "enclosure." As crazy as this seems, that's how it is.