12" Alpine Type S in a Ported Box

[Darkshines 10+ year member]

Hey everybody, just registered, read through the stickies, and decided I'd make a post.

My roommate had two Type S in a terribly tuned and built box, and he severely underpowered them. He overdrove the amp and blew one of the subs, but the other one was still working and I took a look at it and it seems ok. We hooked it up by itself and it wasn't distorting so I think it's still healthy.

Anyways, he gifted his sub, box, and amp to me. I have a 2004 Pontiac Grand Am GT, with Alpine Type R 5.25 comps in the front, and Type R 6x9s in the back off an Alpine deck. I've been putting off getting some low end for a while, and figure I might as well take advantage of what he gave me for free.

So, the plan is to scrap the old box and build a new ported box for the one sub. Alpine suggests a volume of between 1.25 and 2.00 cubic feet for a ported box, so after reading the stickies, I examined the "Free Box Plans" thread, and took a look at the schematics for a 1.6 cubic foot box tuned to 32 hz.

I've never did any graphic modeling or anything, but I downloaded a copy of SketchUp, and gave it a shot. An hour later, after thorough reference to the free box plan schematics, I came up with a model of the box:

Any tips? Suggestions? Criticisms? Anything? Good box? Bad box? Should I go sealed instead? I'm new to all of this really, so feel free to spill your knowledge.

Thanks in advance.

edit - Yes, I know there is no top on it. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

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[91Chevy 10+ year member]

The cutout for the subwoofer isn't actually 12". Download the factory tech specs, and it will tell you the mounting diameter.

 

[jmanpc 5,000+ posts]

1.6cf seems a bit on the small side for a 12" ported. Is that what Alpine's spec is? If so, go ahead and build away. And like was mentioned above, don't make the cutout a full 12"

 

[Darkshines 10+ year member]

The cutout for the subwoofer isn't actually 12". Download the factory tech specs, and it will tell you the mounting diameter.

Thank you very much, it's actually 11.4". Question two, is the box that I found in the sticky a good box, or should I build it exactly to Alpine's specificiations?

1.6cf seems a bit on the small side for a 12" ported. Is that what Alpine's spec is? If so, go ahead and build away. And like was mentioned above, don't make the cutout a full 12"

Alpine lists between 1.25 and 2.0 cubic feet, with 1.55 being the optimum.

 

[DonCorleone 10+ year member]

Thank you very much, it's actually 11.4". Question two, is the box that I found in the sticky a good box, or should I build it exactly to Alpine's specificiations?


Alpine lists between 1.25 and 2.0 cubic feet, with 1.55 being the optimum.

Go with the one in the sticky, most of the time you can build a better box then what the manufacturers put their recommended box size at.

 

[Darkshines 10+ year member]

Go with the one in the sticky, most of the time you can build a better box then what the manufacturers put their recommended box size at.

Awesome! Is there an easy way to increase the tuning frequency a few hz? Ideally I'd like to get to 35 hz. I imagine it'll involve lengthening or shortening the port.

I read somewhere hear that you're supposed to tune several hz higher than the desired frequency, any truth to this?

 

[Darkshines 10+ year member]

Bump!