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I need help with subwoofer box designs!!! Answered

I've got this new alpine (well not new, but it still works) 12 inch subwoofer. The box it's in was probably alright for in the trunk of the car, but I'm planning on using it inside, as my sub just blew. Here's the size demensions of it: 15" wide, 16" high, and 13" deep. There's a hole about 3" x 2 1/4" in the back for the wire to come out. I was planning on using the internal amplifier from the blown subwoofer, in this box, but I need to cut a hole to fit the amplifier in. It sounds really punchy, but for a 200 watt subwoofer (that's rms) it doesn't shake my floor at all because it's basically a sealed box, the sub comes out the front, should I cut a hole in the front or side for a port? What if I used the pipe out of the blow subwoofer box, or is it specifically tuned for the 8" that was in there before? Thanks for any help.


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12 years ago

The port was tuned to best fit that 8" speaker. Basicaly, the diameter and length of the port tube will determine the port frequency. Try looking it up on google...i'll post the formula later if I find it. Your sub will have a punchy sound in a sealed enclosure and a deeper more boomy sound from a ported enclosure. Also, look up your sub online and see what the specs are for box volume(internal airspace) on ported vs sealed recommendations. To get the maximum boom from your sub. Put it in a ported box with an internal airspace equal to the recommended specs. Don't forget to account for the airspace the magnet is going to take up inside the box. The port tube should be placed on the same side opf the box as the sub face. So sub and port on same side. To tweak it even more you can play a test track with different low range frequencies to see which frequency matches your vehicles ressonant frequency. this wil be easy to determine because your car will vibrate more when the output frequency matches that of your vehicle. Then it's just a matter of stopping all the rattles using sound dampening mat or foam. Anyway.......once you find your cars ressonant freq, you can adjust the length of the port tube so that specific freq will be projected the loudest from the port. Basicaly this will turn your entire car into a speaker box and you will be able to hear your music from further away. At least the boomy part of your music. Let me know if I can help, or if ya have any questions. -Truespin