Vented box for Alpine Type R

I've got an Alpine SWR-1221d (last year's model - 300w rms), and I'm looking to build my first vented box for it. I've been searching the internet for a while, and I can't seem to find the tech sheet for the sub that gives Alpine's recommended vented enclosure diagram. So I'm hoping that you guys can give me some input on volume, tuning frequency, or just dimensions for the box. I'm definitely looking for more spl out of this box. It's in a small sealed box as it is. It'll be getting 250w rms. Any help is appreciated.

ermm i've looked into the alpine stuff and alpine don't giv a reocmmended box size for ported. the standard box size in sealed is 0.7 to 1 cubic feet so lookin at other subs you probably need a 1.5 to 1.8 cubic feet box. ported to about 32hz. use a 4 inch round port about 13inches long. dats all i can say, hope it helped6* Rockford T2's

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I was thinking I'd go with ~2 ft^3. But it's the tuning that I'm really wondering about. I was reading through some old posts and Alpine Guy said he ported his box and tuned it to 45hz "and it was stupid loud"( here). Now my question is, why did he tune it to 45 instead of the usual 32 or 37? Is the higher frequency make it seem louder because most music is staying closer to 45hz and not dipping down to 32 as much? Or what?

i think ur goin along the right trak cus i've heard that most compettion vehicles are tuned to about 50hz. i think that the sub is most musical at this stage. one sec.....i think it wud be ideal to tune it to about 35hz from reading the specs. if u r looking to get sum spl out of this sub it is not worth it, this sub is more musical so stick it in a sealed box or a 1.5litre to 2.0 litre boz tuned at 32-40 hz. this is entirely your choice6* Rockford T2's

6* POWER AMPs

BLACK CORRADO

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