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Choosing an enclosure alignment depends on what your client is hoping to gain from an audio system. Here’s how each enclosure measured up. WORDS BY CAMERON “CHIMPO” POWELL
It’s often difficult to describe the audible differences between alignments of subwoofer enclosures. In the beginning of my career in mobile electronics, I used the program WinISD to design random enclosures to see how the responses would change from alignment to alignment. Back then, I also had the opportunity to build some of those designs myself. Additionally, I sent other designs to people around the country to see how they would perform in real life applications rather than just viewing computer-generated graphs. At LIS Audio, we traditionally build or install four different types of subwoofer enclosures. Our go-to professional window tinter, Steve Newendyke of Cutting Edge Window Tinting, wanted to add a bit of bass to his factory system. We installed the amplifier and used a prefabricated enclosure with plans for a custom enclosure later down the line. We figured this would be a great opportunity to test the different options to see and experience the results. I will be covering these designs used in both daily driving and “Show Car” applications. Here are some key details on each of the four:
adding or subtracting to the internal air space, which will change the frequency response of the driver installed in the enclosure. This design is commonly used in Sound Quality (SQ) competition as it provides a very accurate and tight response, though it does lack a bit in output, comparatively. Sealed alignments are one of the most commonly found enclosures in car audio due to their ease of design and petite size.
Sealed (Acoustic Suspension): The interior of this enclosure has an airtight seal from the exterior environment. A sealed enclosure alignment can be tuned by
Vented (Ported or Bass Reflex): This enclosure design is commonly found in the car audio industry, and applies to both prefab and custom designs. It offers
50 Mobile Electronics June 2020
the ability to tune the enclosure close to, or around, a specific frequency. To tune this alignment, one must change the diameter and length of the port against the amount of the internal air space. Vented enclosures are more ideal for output as opposed to sound quality applications, which is why they are commonly found in Sound Pressure Level (SPL) competition audio systems. Dual Reflex Band-Pass (6th Order): This design is like that of a single reflex bandpass enclosure, except both chambers are vented. The two chambers must be tuned 180 degrees out of polarity from
