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The DD Box

In order to get the most performance from these non-optimum applications we have taken a different design approach. Vehicle interiors have limited space, so we started our research on making the most bass energy from a specific amount of space. The key is to extract maximum energy from a limited resource, cargo space.

We engineered a high efficiency type of ported box, then set about engineering a speaker to optimize the box energy. We keep the moving mass low, energy high and add a suspension with high restoring force to help control cone motion. This means that the subs will not have to rely on the box for their loading.

The vehicle itself will offer some loading to the system, and the transfer function will make the system play an octave lower than the tuning freq. So, if you could find some speakers that could stay in control below the box tuning, subs that are really tuned to the box loading plus the car loading, you could design a system to play low, loud and do it in a relatively small box. That is the DDbox.

Each Sub Series we make is designed to work in the DDbox system. Each size sub in the series is designed for the same airspace and same response. They all get the same motor, the same spiders, suspension throw and power handling. The 10 inch size will play just like the 15, but do it in a much smaller space.

Box Sizes for High Efficiency Subwoofer Systems.

^ft = cubic feet | sq" = square inch
All volumes listed are after vent, and subwoofer displacement; a.k.a. NET volume
This chart is for tuning boxes in the 35-40Hz range.

Get the DD Space Makes Bass Shirt.

Volume # & size of Drivers Port Area & Length
0.75^ft  (1) 8" 11.25 sq" vent x 22" long 
1.00^ft  (1) 8"  15.0 sq" vent x 23" long
1.25^ft  (1) 8" or (1) 10"  20.0 sq" vent x 23" long 
1.50^ft (2) 8" or (1) 10"   24.0 sq" vent x 22" long
1.75^ft (2) 8" or (1) 12" 28.0 sq" vent x 21.5" long
2.00^ft (2) 8" or (1) 12" 32.0 sq" vent x 21" long 
2.25^ft (2-3) 8" or (1) 12" 36.0 sq" vent x 21" long
2.50^ft  (3) 8" or (2) 10" or (1) 12" 40.0 sq" vent x 21" long 
2.75^ft  (3) 8" or (2) 10" or (1) 12" 44.0 sq" vent x 20.5" long
3.00^ft (3-4) 8" or (2) 10" or (1) 15" 48.0 sq" vent x 20" long
3.25^ft  (4) 8" or (2) 10" or (1) 15" 52.0 sq" vent x 20" long
3.50^ft (4) 8" or (2) 12" or (1) 15" 56.0 sq" vent x 20" long
3.75^ft (3) 10" or (2) 12" or (1) 15" 60.0 sq" vent x 19.5" long 
4.00^ft (3) 10" or (2) 12" or (1) 15" 64.0 sq" vent x 19" long
4.25^ft  (3) 10" or (2) 12" or (1) 15" 68.0 sq" vent x 19" long
4.50^ft (3) 10" or (2) 12" or (1) 15" 72.0 sq" vent x 19" long
4.75^ft  (3) 10" or (2) 12" or (1) 15" 76.0 sq" vent x 18.5" long
5.00^ft (3) 10" or (2) 12" or (1) 15" or 18" 80.0 sq" vent x 18" long 

  1. Any available space larger than above chart, simply use the chart to determine what multiples of subwoofers you can choose from.
  2. The above info and chart works with all DD Series woofers.
  3. We recommend to allow at least several weeks of playing time to break in DD Woofers, full break in may take many months. DO NOT play subwoofers at max amplifier power in the first couple of days, give the suspensions a chance to loosen up. As the suspension breaks in, the subs will play lower and louder.
  4. After you give the woofers a chance to break in (you'll know when this happens because the woofers will be playing lower and louder) you can start to look at port changes to alter the sound to your personal taste and your vehicles acoustic loading conditions.