need help figuring out sub box net cubes port area etc....

[blkvenm97]

I have an enclosure that was built for my two 12 inch rockford p3s by a local audio shop. I want to know the port area and net cubes and all this about it. All I know is when I had it built I asked them to tune it to 33 hertz. I called them and they just told mme it was built to the specs rockford provides for the p3 which is 1.79 cubes per sub but I'm almost sure this box is bigger than that. I want to know how to measure and get the specs for all this stuff. External demmensions are 37x18x16 and it has a 3 inch wide port. The port is 14.5 inches top to bottom and its 17.5 inches from where the port starts to the back of the box (on the inside). I know it is 3/4 inch mdf I did find that out. Its a slot port on the side. I am wanting to switch to sundown sa 12s but I want to know the exact specs on this box to make sure they're gonna do well in it. The p3s do good in it they slam for what they are but I want to switch to sa12s. I also want to make sure its actually tuned to 33 like I asked...it sounds like it is it hits lows pretty well. I had one 10 inch p3 before this tuned to 35 and this hits the lows a lot better....much better. I know its 12s but I'm pretty sure it is indeed tuned at 33 but how do I find that out for sure? Someone please help. I measured from the inside part of the port over and subtracted 1.5 inches on all sides and devided by 1728 but it cammme out to 4.5 cubes net before sub displacemment....does that sound right? I'm not sure if I'm doing this right or not. How do u figure out port area? I want to get oppinions on how well sa12s will do in this enclosure but I need to find out the enclosures specs first. Someone please help! Thanks!

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[LosIsATool 5,000+ posts]

1.79 per sub will look big if all you have even seen is 1.25 prefabs

 

[blkvenm97]

I've seen other boxes made for p3s that weren't this big....also seen a lot of boxes in the 4 cube net area that were about the same as mine as far as external demensions. Not saying it looks biig but I wanna figure out how I can figure all the specs up with the info that I have available

 

[blkvenm97]

Also when I measure everything to the right of the port (port not included) and subtract wood thickness and devide by 1728 I'm coming up with right at 4.5 cubes net before sub displacement. Does that sound right? Surely sub displacement doest subtract that much does it? According to rockfords website the p3 are .106 cubic feet displacement...that would still leave it close to 4.3 cubes net wouldn't it? I may not be doing this exactly right I don't see where I could be that far off though. Can someone help please....and I don't deal with prefabs btw

 

[blkvenm97]

Can someone please tell me how you go about figuring out all the specs with the info that I have available? I believe this may very well be a pretty good enclosure for sa12s but I want to know for sure what the specs are not only to see how it would work with the sas but id just like to know the exact specifics anyways