KenSchoen Posted December 27, 2014 Report Share Posted December 27, 2014 Hello Everyone. My friend recently purchased a ported box and has two Rockford Fosgate P3's in it. It sounds great....but I'm a little confused about a couple things. 1. It's a two sided box with a slotted port in the center. 2. Each side is roughly 3.3 ft3 3. The dimensions are these. H 14.6" W 38.2" D 25.2" wood thickness of 5/8" 4. Port dimensions PH 13.25" PD 19.6" PW 3" This is what I don't understand. If you want between 12 and 16 inches of port area per cubic foot....why is the port area almost perfect for one side of the box? Wouldn't the port area need to be double for a two sided enclosure? If the port size doesn't need to be doubled when it's a center port then what would the tuning be? Thanks everyone Link to comment Share on other sites More sharing options...
Aj11 Posted December 27, 2014 Report Share Posted December 27, 2014 haha 5/8s And no way each sub has 3.3 cubes that's external. internal with port it's prolly 1.1cubes each. this is why prefab boxes suck! cost 4x as much as a good homemade box. but as a guess your box is tuned between 37/42hz with a Very.small port. jvc deck stinger 1800 front hc 2000 kinetic rear 2 runs of 1/0g big 3/4 ct 60.4 2 ct 1400.1 ct EXO 15 d1 lots of deadner type r comps front stage 6 kicker tweets rear stage lots of great stuff coming soon ho alt more bats ct comps for front stage more deadner sweet amp rack lots of L.E.D lights new deck (thinking 80 prs, or flip out) Link to comment Share on other sites More sharing options...
KenSchoen Posted December 28, 2014 Author Report Share Posted December 28, 2014 haha 5/8s And no way each sub has 3.3 cubes that's external. internal with port it's prolly 1.1cubes each. this is why prefab boxes suck! cost 4x as much as a good homemade box. but as a guess your box is tuned between 37/42hz with a Very.small port. It's quickly becoming obvious that many on this forum don't take questions seriously. A simple math equation shows that the internal volume of this box including port and port walls is 6.8 cubic ft. Either you didn't even read what I wrote or read it and did't put any effort toward coming up with an actual answer to my problem. Link to comment Share on other sites More sharing options...
KenSchoen Posted December 28, 2014 Author Report Share Posted December 28, 2014 I also never said if this was a prefab box or not. I also said the subs sound VERY good in this box. Link to comment Share on other sites More sharing options...
CleanSierra Posted December 28, 2014 Report Share Posted December 28, 2014 I get 6.21 cubes net(rough calculator math) before sub displacement. You've left out some vital information: What size subs is the box built for? I'm assuming 12s. Here is your answer though: port area per foot is a general rule of thumb and a bad one at that. As long as there is sufficient OVERALL port area to satisfy the need of the subs, that's all that is needed. If you've got some P3 12s, 20" of port per DRIVER, should really be sufficient. I'd personally want to see slightly more, but that's just me. A P3 12" doesn't have a crapload of Xmax and that's likely why the subs sound fine in that box. As far as tuning goes, the box is right around 27-28 Hz based on your measurements(assuming my math is worth a damn, but I'll bet I'm close) Im not the one you want to try to troll. Just a fyi for you. Link to comment Share on other sites More sharing options...
KenSchoen Posted December 29, 2014 Author Report Share Posted December 29, 2014 Thanks man Yeah they are for 12's and they do honestly sound pretty good. Are there any website or is there a formula to calculate desired port area per given sub size and xmax? Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted December 29, 2014 Report Share Posted December 29, 2014 Indeed there is: http://www.carstereo.com/help/Articles.cfm?id=31 "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds: Link to comment Share on other sites More sharing options...
Cj Kumz Posted December 30, 2014 Report Share Posted December 30, 2014 Personally I think you will be better off with a minimum area of around 30 sq inches per sub. Also according to your dimensions I'm getting about 26-27hz tuning which I think is a tad too low. Vw Polo Pioneer Deh-6050UB Sundown Saz-3500d DD Audio 9500 15'' 5.5 cubic feet box with 10 inch port @ 38hz I live to hear the Bass drop!!! Link to comment Share on other sites More sharing options...
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