SpydreX Posted August 29, 2018 Report Share Posted August 29, 2018 Its been a long couple months but I have stripped out everything in my 97 Jeep Grand Cherokee to make room for my next build. I installed damplifier pro in pretty much every possible location, spray foamed every single void, and am now ready to start on building a wall to the B-pillar. I am going to maximize my space and build it around every countour of the car so that I have a max Gross of 62 ft^3 to work with. I want to do 2 layers of 3/4" birch and then brace on the inside as needed. My original plan was to do a simple flat wall ported enclosure with 4 18" Fi teams so I mocked up some 18.5" circles with some particle board to see if my sub placement would work. I am glad I did this because it made me realize that even with the subs touching the sides of where the wall would be accounting for the 1.5" of material i'd only be able to make my port 7 inches wide which is nowhere near enough because I only have 38" of height to work with unless I made the port wedge shaped "not sure if thats possible". So I went back to the drawing board and thought hey why not do a 4th/6th order BP? I could easily fit all my subs in the enclosure and have a giant port around 600sq in. Only problem is that I don't really know all that much about BP enclosures and how much room they take up. The Fi teams recommend 5-8 ft^3 lol what a range but would it be possible to build a series tuned 6th order BP or do I just not have enough room? If not enough for the 6th order then i'm sure a 4th order would still work right? I know 3 18s in a series tuned 6th order BP is definitely possible because "Jeep and Bass" just did a video on a build he did in a cherokee which has very similar dimensions to the GC. Been trying to do research on 6th orders but there is not a lot of information out there it seems. I can't find a straight answer on how to calculate the box volume you need because some people talk about ratios and other people are totally against it. Been learning to use Hornresp as from Triticums testing it is one of the only softwares that accurately model series tuned 6th order BP enclosures. I still have a lot to learn but I knew one day i'd want to learn about them eventually so better now than later. All criticism and input is welcomed. If you need anymore more information then I will gladly give it. Added an image of what I got to work with. I actually just finished the doors and roof so the picture isn't completely up to date. Oh and the fact that there is a 2x6 bolted and PL'd behind the B-pillar along with 2x4s acting as a ramp flush to the rear cabins floor pan. I will take another picture in the daylight and update with some more angled shots. Link to comment Share on other sites More sharing options...
CleanSierra Posted August 29, 2018 Report Share Posted August 29, 2018 4 18" Team Fi's will absolutely shred a 1.5" walled enclosure. Throw that idea in the shitter right now. Unless you use so much steel to brace that the Jeep is dragging is ass around curves when you're driving it... Minimum of a 2.25" layer box, I'd probably to 3" to be safe and still brace with metal crossmembers. How much power do you plan to run on these subs? 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...
SpydreX Posted August 29, 2018 Author Report Share Posted August 29, 2018 Even with it braced with 2x4s in the back and a 3.75" baffle in the front? And I plan on putting 22000watts to them. I can always add more bracing, got plenty of birch. I can also put in stripper poles where ever needed. The places where it would be 1.5" would be screwed and PL'd to the frame. The sheet metal is fairly thick compared to other vehicles. Still no bueno or should I just go ahead and add more layers instead of compensating with internal bracing? Link to comment Share on other sites More sharing options...
DiBo Posted August 29, 2018 Report Share Posted August 29, 2018 6 hours ago, SpydreX said: Even with it braced with 2x4s in the back and a 3.75" baffle in the front? And I plan on putting 22000watts to them. I can always add more bracing, got plenty of birch. I can also put in stripper poles where ever needed. The places where it would be 1.5" would be screwed and PL'd to the frame. The sheet metal is fairly thick compared to other vehicles. Still no bueno or should I just go ahead and add more layers instead of compensating with internal bracing? If you're going to PL the 1.5 section to the frame you're good. Any wall not completely attached to structure should be at least 2.25. 3 layers with glass is plenty. I'm new at this but I am a certified Carpenter and the tensile strength of 3 layers with glass would be bulletproof for any sz woofers. Link to comment Share on other sites More sharing options...
CleanSierra Posted August 29, 2018 Report Share Posted August 29, 2018 I'd be comfortable with 2.25" for a box running those subs in that power. I would NEVER consider a 1.5" box for that equipment, no matter how it's braced. Just because it doesn't blow out, doesn't mean it's a solid enclosure. Making it as stiff and unable to flex is the goal. The more it flexes, the more energy you've lost and in turn, loudness. I would run 2.25" with bracing and call it a day. Unless you're going with a full 2X4 outer cage or something. 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...
SpydreX Posted August 29, 2018 Author Report Share Posted August 29, 2018 Well my original idea was to do the 2x4 outer cage but after I realized that 4 18s wont give me enough space for enough port area with a flat wall I now am looking at 4th/6th order BP designs. I don't know how much space I am going to need though because I don't know how to calculate it the correct way. I just know they are absolutely huge so I might have to take away the 2x4s if I end up not having enough space for the BP. I can't find anything online about how to correctly design the BP enclosure around the subwoofers you are using unless you go with ratios but there is a lot of conflict on how ratios are the wrong way to design the enclosure. Can anyone with expirence point me in the right direction? I'd really like to do a series tuned 6th order BP if room allows it but if not then I will go with a 4th order like most people end up doing because of the work involved with the 6th order. Link to comment Share on other sites More sharing options...
CleanSierra Posted August 30, 2018 Report Share Posted August 30, 2018 6th orders(and 4th BPs for that matter) are rarely "right" out of the box. Many need tweaked and re-tuned regardless of design. Cabin gain definitely has a huge effect on outcome. For example, my 4th BP in my old blowthrough started out at a 148(in kick) on initial fire up. I made tweaks to sealed side(shrunk by half a cube each) and my ported side(never changing port area) by shrinking and adding 45s and also bracing the back wall of my cab with steel and eventually got the number to 154 in the kick and doing a 151 at headrest. If I'd chalked it up to a "failed" design, I never would have discovered those hidden DBs. The reason I bring that up is to say this: simple can sometimes be best. Start with a 4th BP(due to simpler) and less to actual separate chambers that can be tweaked independently from each other.. I am one NOT to hold ratios with any real weight either, rather overall port area and volume of chambers, along with tuning etc. You're going to need roughly 5 cubes sealed per 18(20 cubes total) and around 8-10 cubes ported per sub. That's going to be somewhere in the 60 cubes total range. You don't have that in a GC, NO way. Per your measurements, what's the total volume you have available, with a square-edged shell(I'm talking 90° corners)? 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...
SpydreX Posted August 30, 2018 Author Report Share Posted August 30, 2018 Alright so I went to my jeep and took pictures and more detailed measurements. If I make a rectangular box with perfect 90s in all 8 corners I have 51.64 gross cubic feet to work with accounting for the space in the back needed for my battery bank. If I include the slope in the front, and where I can build around the wheel wells I have a total of 66.65 cubic feet to work with accounting for the battery bank. Now 5 cubes sealed and 8-10 cubes ported sounds like a lot but you are the expert. I do know however that Galen "a.k.a Bassman" fit 6 15" SSA Evils in his GC and it sounded pretty good imo and that was in a 4th order BP. Link to comment Share on other sites More sharing options...
DiBo Posted August 30, 2018 Report Share Posted August 30, 2018 Download imgbb and upload your pics there. Tap the pic after and select direct link url... Copy and paste Link to comment Share on other sites More sharing options...
CleanSierra Posted August 30, 2018 Report Share Posted August 30, 2018 Most modern 15s only need ~3 cubes each sealed, so 6 would be in the 18 cubes range. It might not sound like a big difference between 20 but 2 cubes adds up. You might very easily be able to get away with less than 5 cubes sealed per 18" sub but be aware that all your lows come from the sealed chamber in a 4th BP. The smaller you make the sealed section, the less volume it has to reproduce monster lows. On a side note, I've never personally done a design for the Team Fi subs in a 4th BP due to them not being 4th BP friendly(T/S specs wise). Has something changed in their specs allowing them to be more friendly in this enclosure type? Have you done the research to know this yet? I remember the old Ascendant Audio 4" coil "Team" version worked in a 4th BP, whereas the Fi version didn't. You might want to check on this. 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...
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