High-Performance Enclosure Design
Tiny subs in tiny boxes give you a sound that’s…well, tiny. If you are looking for real bass, you need a real box. In this post, you’ll learn about how to create a high-performance enclosure.
In order to get true high performance, you have to make sure the woofers have enough air to “breathe.” The more air you make available, the higher the potential sound pressure level (SPL). In each SoundQubed subwoofer series, the parts are mostly the same. This means the HDS2.115 has the same amount of throw and force available as the HDS2.112. The smaller sub in the right space will outperform the larger sub in too small of an airspace.
The first step in getting major bass in your vehicle is to allocate the space for your enclosure. If you really want to flex some sheet metal, the old adage applies, “there is no substitute for cubic inches.”
You don’t have to use a large amount of enclosure space to make a loud system. With a box built for high performance, loud can be done with a single subwoofer in the right enclosure. The amount of loud needs to be determined as you figure out what space you plan to give up. Really loud bass, where you have to scream at your passengers, can be done on a single or double woofer setup. Stupid loud bass, where there is no point in trying to communicate in the vehicle, takes more space and bigger/more subs. F@#$ing crazy loud bass, where it is impossible for the car next to you to communicate inside his vehicle, takes even more space, even more subs and a gazillion watts of power.
If you squeeze a giant box into your trunk, it will be extremely loud. Unfortunately, all you’ll hear is the box rattling. For a rear-firing box in your trunk, make sure it doesn’t seal off the trunk from the passenger compartment. You need to leave space for the sound waves to pass back into the interior of the car. One method is to make the box as low profile as possible. The waves can then pass over the box and enter the cabin via the seat back and rear deck. You could also reduce the width of the box so the waves can pass around the sides and into the cabin.
If you have a hatchback, keep the box as far back in the vehicle as possible. Also keep the port as far to the rear as possible.
A strong box is essential in a high-output system. Your box should be free from air leaks, and braced internally if the volume exceeds 2 cubic feet. Internal cross bracing is far more effective in making a rigid box than doubling the wood thickness. Doubling the wood thickness adds a great deal of weight to your vehicle. Also, the added wall stiffness is less than stiffness added by cross bracing. Try to cross the braces at the same point so that they add strength to each other.
If your cuts are messy, the inside seams of the enclosure can leak air and create weakness in the box’s structure. One way to strengthen these joints is to use gluing cleats on the inside seams. Stronger, more air tight construction is crucial to a high-performance enclosure.