Comparing Enclosure Alignments for Optimal Performance Let’s take a look at some details and data from each enclosure I built for this experiment. Sealed Enclosure The sealed enclosure was built using ¾-inch MDF to specifications, like a prefabricated sealed enclosure for the 12-inch subwoofer. It has .81 cu. ft. of inner air volume. The sealed enclosure comes to about 1.19 cu. ft. of external volume with the measurements being 14” by 14” by 10.5”. This can help show how a sealed enclosure performs against the rest of the enclosures and how much room it may take up in the cargo area. Many of the sealed enclosures we build at LIS Audio are fabricated into the rear hips of vehicles, dependent on space allowed, but generally have about the same amount of airspace as a generic sealed prefab. It is very easy to see on the WinISD graph that the initial curve of the sealed enclosure, which is the blue line, has a very smooth roll-off. This shows there might be a fairly smooth transitions from note-to-note as it gradually gets weaker the lower the notes go. From the DM-RTA readings, the most pronounced frequencies in the vehicle are between 45Hz and 55Hz. I set the pink noise to play the same 60 seconds of a specific section of the track for every trial to maintain consistency. This alignment produced an average maximum of 105.0dB. This setup performed most music genres well, overall. Prefab Vented Next, we have the prefabricated vented enclosure, single bass-reflex. The enclosures external measurements are 13.25” by 16” by 18” and the port appears to be tuned to 38Hz. This would put the enclosure at 2.20 cu. ft. of external volume—which is how much room it will take up in the intended cargo area. The interior volume is estimated to be 1.5 cu. ft. before sub displacement. As mentioned earlier, this alignment is often used in SPL competitions, and is commonly built by shops due to the ease of design. The prefab enclosure design depicted on the graph (red line) shows that we can expect an increase in output, which
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