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Clean3
05-03-2006, 09:00 PM
Hello Everybody I'm fairly new in this forum and need some help. I want to build a sealed box for my 15"CVX (powered by zx 1000) but i dont really know how big to make it to get the sound i want. I have an 02' 325i. I want it to hit hard but sound clean in the beamer. any suggestions or questions?

thanks alot for those who will take the time to help.

DFW40
05-03-2006, 09:21 PM
Take a look at their site and go from there

Clean3
05-03-2006, 09:34 PM
ok so i'm assuming 5.2 cu. ft. will probably be the best for the speaker but how much space does the actual speaker displace so i know how to calculate this. I think the dimensions i have to work with are 30" in length X 16.5" High X 28" Deep (that's all the way to the very end of the trunk which i probably dont want to make a box that goes that far, how much space should i leave from the face of the sub or front of the box, to the end of the trunk)

Clean3
05-03-2006, 09:34 PM
Does the shape of the box give you a different sound, square vs rect.?

JimBo930
05-04-2006, 12:36 AM
go to this site www.The12volt.com

Clean3
05-04-2006, 02:25 PM
thanks that's a great website a little too technical for me but i guess i'll catch on i'll just try reading more of these posts and learn.

j3bus2k3
05-04-2006, 02:32 PM
You cant really go off your maximum lengths in the trunk unless you want to build the box INSIDE the trunk. Otherwise, you need to measure your trunk opening to see how big of a box you can actually stuff in there. A 15" Woofer would probably displace about .2ft^3 though.

Clean3
05-04-2006, 04:21 PM
30" X 16.5" are my opening dimensions

DFW40
05-04-2006, 04:29 PM
I had a 2002 BMW and anything more than 3-4 cubes and your trunk will be gone.
Are you going sealed? If so 3.25-3.5 should be perfect. Also you should take out your rear speakers and if you have the skihole remove the plate that covers it and the pad.


this is not that technical, just plug in length, girth, height etc
http://www.the12volt.com/caraudio/boxcalcs.asp

Clean3
05-04-2006, 05:37 PM
yea i got the rear speaker out and the ski hole plate removed as well. HAVINGFUN do u have any pics of ur box or dimensions?

Clean3
05-04-2006, 05:46 PM
never mind i just figured out u can click on your gallery pics, duh.

Clean3
05-04-2006, 10:04 PM
ok i think i 've got my set measurements, 30"(width)x21"(depth)x16.25"(height) i believe that comes out to 4.6 cu. ft. after the disp. of the actual sub. what do u guys think should i build that? how about filler for sound deadening i've been reading that this helps. Does it? Does it add or take away from the cu.ft. total? And last but not least where can i get it?

joeldirt
05-04-2006, 10:06 PM
You cant really go off your maximum lengths in the trunk unless you want to build the box INSIDE the trunk. Otherwise, you need to measure your trunk opening to see how big of a box you can actually stuff in there. A 15" Woofer would probably displace about .2ft^3 though.


Was just going to suggest the same thing.

Clean3
05-04-2006, 10:11 PM
those final measurements will fit through the opening but anybody have anything on the question about filler inside the box?

joeldirt
05-04-2006, 10:30 PM
those final measurements will fit through the opening but anybody have anything on the question about filler inside the box?

It isn't absolutely neccesary, but by adding, fiberglass, ployester or dacron batting.... YOu can find that stuff at a fabric store, what they use to stuff pillows... works good... 2 bucks a bag which is enough for your box, I'd maybe get two actually for your own personal preference. . . But you typically use the stuff for two reasons..... it can reduce the reflections inside the box which basically gives resonant peaks and drops when you get more towards playing mid-bass, and high bass notes... So that is more for full range speakers... You got a fifteen.... I really doubt you are going to need batting for this purpose..... Because it will provide no benefit for that speaker....

But maybe you might benefit from the second..... It is said that by fully stuffing the enclosure with the batting, you can increase the "effective" size of the enclosure from 15-20%. So.... if you do not want to take up all of your trunk space with a big ol' box, then stuffing the box with batting will slow down the sound waves in the box making the speaker "think" its in a bigger box which will play the lower notes how you like.

So I hope that this was helpfull for you.

Clean3
05-04-2006, 10:35 PM
very helpful thx

Clean3
05-04-2006, 10:38 PM
now is it true bigger box louder sound?

joeldirt
05-04-2006, 10:57 PM
now is it true bigger box louder sound?


To build an effective sealled box, you want to make sure that the sound coming from the back of the speaker cannot be heard... Air tight enclosures... Air tight... Only the sound from the front of the speaker should be heard... The sub is working agianst a spring of air inside the box... This "spring" is what causes the speaker to opperate in its designed range of motion... Too big of a box and the "spring" will be too lose, causing the woofers motor to "bottom out".... Too small, and the spring will be too tight causing the sub to be restricted, and also gives a heavier load on your amp, which could cause your amp to turn off periodically to cool down. Every speaker has it's own set of perameters, which require a specific range of perameters for the box it will play best in... You want to try and operate and design boxes to fit each subwoofer... Allot of people pay no mind to the perameters and design a box that is completely wrong for the sub and they do not get the sound they were really hoping for.... Sealed boxes give you the deepest bass if you require a small enclosure... More box volume and larger port area will increase the SPL, but a small ported enclosure does not get lower then a sealed when dealing with small volume requirements. So the drawback equally of a sealled box is that if you are dealing with a larger space, and can benefit from a ported box... the sealed is then blown away in an SPL competition. Sealled boxes generally maintian sound quality in comparison to ported, or band pass systems.

In other words, a sealed box probably for your car would be best for the fifteen... To build a ported box for it to get the best output would be far too large.... So a sealed box that is 3.00 thru 4.5 would get as "loud or as Deep" as you would want. (((GENERALLY)))

but since you have room for 5.2, and the max dimensions you provided are aproxiamtely 8 cubes.... why not port??? 5.2 cubes worth would give you a good sized ported box. Shorten the depth of the box down to 20" instyead of 29 or 8 which ever it was.... put two round 4" ports that are 12" in length will give you a total box volume of 5.2 cubes, and after displacement you have a box that is about 5.0 cubes tuned to arround 30 hz... (28.somthing) That will for sure get allot louder then your selad box. Think about it.

Clean3
05-08-2006, 01:45 PM
so I did my box this weekend 5.1 cubes sealed but I'm not liking it. The bass response is just not how i wanted it, so i'm thinking of making a smaller box, maybe a 1-1.5cubes less and maybe this way i'll get a tighter response from the sub? That box is great sq but I know for a fact it can be way louder( i know ported is loud, but i dont want ported). I know it also has to do with the fact that my trunk is sealed off, i did take out the rear fill and the ski hole. What could i possibly do to make it a little better? Do you think if i fire the sub into the car through the ski hole it will be louder instead of having it face the trunk lid.

Clean3
05-09-2006, 11:31 AM
I see nobody wanted to input on my question but that's ok. I chopped the top off the box and reduced it from 5.1 to 4.05 or so cu.ft. What a difference , now i'm subbin' !!! Dyanamat is next.

joeldirt
05-09-2006, 11:44 AM
I see nobody wanted to input on my question but that's ok. I chopped the top off the box and reduced it from 5.1 to 4.05 or so cu.ft. What a difference , now i'm subbin' !!! Dyanamat is next.

right on man.. I figured 3-4.5 would be good for a sealed box with that sub. I am glad the box ended up turning out good.

Clean3
05-09-2006, 11:52 AM
thanks for ur input "joeldirt"