Rich65 Posted May 11, 2012 Report Share Posted May 11, 2012 (edited) I was wondering if anyone has had experience making a jl audio 13w7 4th order bandpass for 2 subs. I have tried to use the box calculators online but I cant figure it out. I have also emailed jl audio several times to see if they would know what the chamber sizes would be but so far havent recieved any responses from them. I am putting the subs in the trunk of a 1965 chevelle convertible so I would like to bring the port into the cabin. Im not sure how having no cabin pressure will affect the sound so im thinking tuning lower then the normal 45hz, maybe like 35 hz or so. The specs on the subs are: qes : .476 qms: 7.517 qts: .448 fs: 23.5hz vas: 104liters xmax: 32mm sd: .0693m sq Pe: 1500 no: .269% Dual 1.5 ohm vc I have a huge trunk so size isnt an issue. Some people were saying 4th orders were a 2:1 ratio ported/sealed but I have also read that isnt always the case. So if anyone can help with the box calculator that would be sweet. Edited May 11, 2012 by Rich65 Quote Link to comment Share on other sites More sharing options...
Rich65 Posted May 11, 2012 Author Report Share Posted May 11, 2012 Not sure if it matters but ill be running 1500rms to each sub in 3 ohm. Quote Link to comment Share on other sites More sharing options...
brent379 Posted May 11, 2012 Report Share Posted May 11, 2012 I hope u have alot of room cuz bandpass boxes get very big very fast... Ok from what I understand how 4th orders work is you have one sealed chamber and one ported chamber...choosing the chamber sizes isn't hard but u need to figure out what ratio you want.... The sealed chamber is just what is recommended for your sub...if your sub recommends 2 cubes sealed and your running two subs then u need a 4cube sealed chamber... (im sure those numbers are irrelevant to you but im just using them as an example) The way ratios work are 1:1 2:1 3:1 4:1... You can throw in half also... 1.5:1 2.5:1 and so on...idk what the biggest ratio you can go tho... Also the bigger your ratio is the peakier your box will be... The lower the ratio the flatter response you will get.. With a flatter response I think you get a wider frequency range which means it will be more musical ... Once you decide your ratio that's where you get your ported side from. The ratio means that for every 1 cubic foot sealed....you need that much or more ported... For instance say you want a 2:1 ratio...and your sealed side needs to be 1.5cuft...your prted side would need to be 3cuft... As far as tuning goes im not sure wat tuning lower would do...the sealed side of the box controls the low frequencies and ported side is for your higher frequencies... So if you want it to hit lower make the sealed side a little bigger...since bigger sealed boxes hit lower...and smaller sealed boxes won't hit as low but will make your bass tighter. Quote Link to comment Share on other sites More sharing options...
Rich65 Posted May 11, 2012 Author Report Share Posted May 11, 2012 Right on man for the help, I just want deep bass, and with a convertible I am just worried that it will end up sounding like shit if i dont make the box correctly. Due to the curves, contours, and 8" step up in the trunk ill be making box entirely from fiberglass, already have the bottom molded and built up, just waiting on size before i cut it to match. Quote Link to comment Share on other sites More sharing options...
n8ball2013 Posted May 11, 2012 Report Share Posted May 11, 2012 whats the car? i do believe this will be the first 13w7 4th order ive even heard about. Quote THERE IS NO BUILD LOG! 1998 Chevy Silverado ext cab Alpine CDA-9887 4 Team Fi 15s 2 Ampere Audio TFE 8.0 2 Ampere Audio 150.4 3 Digital Designs CS6.5 component sets Dual Mechman 370XP Elite alternators inbound! 8 XS Power d3400 6 XS power d680 Second Skin Stinger Tsunami Wiring Sky High A Real Voltmeter not a piece of shit stinger. Link to comment Share on other sites More sharing options...
Rich65 Posted May 11, 2012 Author Report Share Posted May 11, 2012 (edited) whats the car? i do believe this will be the first 13w7 4th order ive even heard about. 1965 malibu convertible, yeah ive noticed not many people like w7's. Edited May 11, 2012 by Rich65 Quote Link to comment Share on other sites More sharing options...
brent379 Posted May 11, 2012 Report Share Posted May 11, 2012 No problem man. Alot of times deep bass has alot to do with the fs rating of the sub...the lower that rating the better and deeper it will play the lows...i believe...and with the low rating of ur sub it should do pretty good. Just make sure that u take all displacements and adjust the box so that you have true net volume ratings of your box...makes a big difference. Quote Link to comment Share on other sites More sharing options...
Rich65 Posted May 11, 2012 Author Report Share Posted May 11, 2012 Well problem solved, I called jl audio technical and I have to say they are the most helpful technical support ive ever dealt with over the phone, emailing was a waste of time so dont bother. He gave me the first set of volumes in like 2 mins but that was tuned to 58hz, So I asked if it could be a lower tune for a convertible, he said sure give me a couple minutes to model it and these are what the box volumes will be for 2 jl 13w7: this is the first set of volumes he gave me 2.0 sealed net 3.0 ported net 100 sq inch port 16 in long tuned to 58hz that was too high for what im putting it in so heres the 2nd set of numbers he gave me after modeling it. 2.25 sealed side net 3.5 ported side net 110 sq inch port 22.5 in long tuned to 52 hz, will go from 31hz to 90hz So thanks to the people that helped out, this is a huge relief. Quote Link to comment Share on other sites More sharing options...
brent379 Posted May 11, 2012 Report Share Posted May 11, 2012 Damn 2.25 sealed is all u need for 2 13w7s??? That's crazy...it should sound pretty good tho Quote Link to comment Share on other sites More sharing options...
Rich65 Posted May 11, 2012 Author Report Share Posted May 11, 2012 Damn 2.25 sealed is all u need for 2 13w7s??? That's crazy...it should sound pretty good tho Damn 2.25 sealed is all u need for 2 13w7s??? That's crazy...it should sound pretty good tho Yeah man i actually had to call him back to make sure it was for 2 because i also was suprised. Quote Link to comment Share on other sites More sharing options...
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