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box building help


Elite Explorer
October 18, 2001
Reaction score
City, State
Red Wing, MN
Year, Model & Trim Level
1996 xlt
i have an 800a2 and two he2 4 ohm dvc 15s in the mail right now. i want good sound quality, but i listen almost only to rap and i don't really care how linear the response of my subs are so long as they pound from 35-65 or so. rockford recommends a 2-4 cubic foot seales enclosure or a 2-4 cubic foot ported per sub. they say a 2.5 is ideal.

sub specs are- vas 23.6, fs(hz) 22, qts 0.51, xmax 13mm. they are rated for 500 rms and 1,000 peak and my amp says it makes 520 by two channels at two ohms so the will be getting right about the rms power.

should i build the box ported or sealed for my application? what about vented? i have seen some vented boxes on ebay and other places and i feel more comfortable building that than a port (i have no experience with tuning a port and don't know how to-- if you suggest ported tell me how please)

i plan on building one large enclosure, but with the two subs seperated so they have their own airspace. how much airspace should i give each sub?

pretty much just tell me what size and ported, sealed, or vented? and i'll go from there.

also, i found a calculator that could suggest either a ported or sealed box, but i need qts for it to work. i can't find the qes of these subs anywhere on the net. what is it?

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any ideas?

if you want them to really pound, go with a ported, but vented is also nice. vented is sorta the next step up from a sealed. you shouldnt make two chambers, but make it one big one, because you are using one amp. im not sure how those subs are wired, and not too confident on what you have to do to wire them with a 2 channel amp. but i have my 3 10s hooked up so they run at 1 ohm stable, which my amp is for. im sure others will jump in.. ask leenjen.. hes the man to talk to for audio stuff. good luck and hope to see pics of your progress.

Vented and ported are the same thing! U can either make a slot port or use round PVC pipe. I would recommend downloading a program called WinIsd, its a great program for making ported boxes. U simply input all your T/S paramaters, then chose the type of box, how many woofers, cuft, desired tuning freq, and it then spits out your approx. vent length and gives you an idea of how your box will sound. I think the general rule of thumb for a port is 10 - 15 suare inches for every cubic foot. So basically for a 5.5 cuft box (shared chamber) you can build one port with about 100sq inches of port (10 x10). As far as the size of the box I would build a 5 - 5.5 cuft box after all displacements. As far as tuning goes for rap i would tune anywear from 35 - 40hz, if you would like alittle more low end try 30 - 35hz. Also for more info on building boxes read some threads on

wiring is no problem the subs are dual 4 ohm voice coils so i can wire each sub to two ohms and then run one channel of the amp to each. i will check out that program- i hope its easier than blaubox which i have been trying to use. i know the box will need to be around 5.5, but i don't know about the porting/venting. can i make it one big compartment and then just have a tall (height of the box) skinny "vent" of the right demensions? i know i sound stupid, but i've never really gotten into this stuff this much. i really want to do this right this time and get the most from my equipment.

also fyi- i will have audiobahn 100 watt rms plates with the tweeter up in the dash and 6 by 9 cerwin vega's in the rear both powered by a pioneer 4 channel at 35 watts per channel rms.

Yes you can make one common chamber box with a single port. However don't make the port too skinny or else you will have some port noise. Those 15's will move lots of air, so i would recommend a 10 x 10 port. When using WinIsd choose a 10 x 10 port and it will give you a proper length.

its really all about preference...I have a sealed box, which I think is killer, and all of the other bandpass (vented) boxes that ive heard, in my opinion, sound like garbage... a sealed box will give you a more explosive, retained bass... most people that I know have sealed boxes and could not be happier. Thats just our opinion...most kids around here who's daddies buy them brand new mustangs, beemers, and whatnot, dont have any clue what they buy...they just get talked into buying the wrong things, let alone build thier own boxes, and know their preferences...thats probably why i havent heard a nice vented box lately. YOU CAN MAKE THEM SOUND NICE THOUGH! Just know what you want, and focus on the required dimensions of your box. Just make sure you look at the sub's manual (if it has one), and it should give you a rough idea of what the measurements of a proper box should be. If not, check out some search engines, you can usually find many informative sites on the web that can help you build your own custom box. good luck.

here's the last part of this hopefully with this i should be able to come up with a proposal at least. where are the specs of this sub on the net? i have searched rockford's site, thezeb, crutchfield etc. and all i can get is what i posted above, where can i find the other values?

thanks for the help everyone thus far. also i did send leenjen a im pointing him over here, an d i'm sure he'll help when he gets a chance.

what do you all think about the set-up? do you like it? i'm getting real good deals on everything and its not all my first choice, but it sounds good to me on paper at least. you think it will sound the way i want?

as long as youre happy woth the set up, who cares what other people say...
it should sound good...One 15 should do the job plenty...but hey, the more the merrier,right?Just don't pound your windows out. After a while all that bass shakes things loose...keep after the little things. As long as you spend some time on your personal specs, and not what other people tell you, you should find yourself satisfied...learn to tweak your speakers on your own...the answers come from within...
I gotta get some pics up, i wanna show you what I did with my setup.

you do get +3dB for each sub you add though :D

Originally posted by Xcalibur00
its really all about preference...I have a sealed box, which I think is killer, and all of the other bandpass (vented) boxes that ive heard, in my opinion, sound like garbage

Bandpass boxes are not ported boxes per se, they have both a sealed chamber and a ported chamber that the sub fires into..... ported/vented (once again the same thing) will not sound like garbage WHEN SET UP PROPERLY. I personally made my box sealed and was happy with that.... now for SPL comps I am gonna have to make a ported box to compete with....

sorry double post POS computer.....

anyways I would recommend a ported enclosure if you listen almost exclusively to rap..... you should get a manual with your subs that tells the Theile/small parameters along with rockfords enclosure reccomendations..... If you dont I can probably dig out the one that came with my rockford sub, it had the specs for the HE2's in it as well....

i listen to rap, but i don't intend to compete and i want it to be nice for daily bumping ya know? i'm gonna go with 3 cubic feet per sub sealed and half filled with polyfill. it gives a total Q of .9 or so.

I think 3 cubes sealed per sub is way too big, plus adding the polyfill will make the driver think it's in an even bigger enclosure. Your proposed 6 cubes in total is more then enough for ported. Btw a properly built and tuned ported box can sound as good, if not better than a sealed enclosure. If your gonna go with sealed try 4 cubes or less in total.

more questions-

can i mount a 6.5" coaxial with the basket out? what are the possible drawbacks etc. will it wreck the high end? what if its not in a sealed situation (like a door) what if it is in a sealed box?

what size enclosure should i make for 5 by 7s? or 6 by 9s if i add them.

then which combination is better---

front stage audiobahn plates 100 rms handling (where to put the tweeter? comes to mine here also) with the front r and l channels of my 4 channel and rear stage 6 by 9 bose 80 watts rms handling speakers mounted at head height approximately two feet behind the rear passengers heads facing forward.

front stage audiobahn etc. with the rear as cerwin vega 5 by 7s (100 watts rms handling) in the rear doors and mounted behind the passengers heads in the same manner both run off of the rear channels of the amp?

or would it be better to run both sets of 5 by 7s off of the rear channels, but mount both on the box behind the passengers heads.

fyi- the amp makes 30 watts rms by 4 at 4 ohms and all of the speakers are 4 ohm speakers

sorry that i keep coming up with crazy stuff, but i need help here? i have no clue what i'm doing anymre.

btw- the plan is now no longer to make a full false floor because i don't like the way it looks with the pockets on the sides and stuff. instead i will be building the box raised up off of the floor of the x so that i can slide things underneath it when i need to. then i will have a hinged door that i can close so that the raised "space" is not visible. that way i will have the most cargo space possible and it will protect my subs from stuff rolling around in the back.

QUOTE]er- why doesn't anyone ever agree. i have gone through so many programs and things etc. and each different person or program has a different idea.[/QUOTE]

I think you should do lots of research then if you want it done right the first time. Go to and read you will learn a lot.[

hey, i've been reading a crapload. including much over on that site and a few others. the personal aspect of the box design i.e.- leaning toward sound quality over ouput etc. is tough for me to decide on my own because i've never dealt with a system this loud at all in the past.

Drew just saw this post after u IMd me, i'm not sure on all this technical stuff I always have professional places build my boxes, but I'd say whatever you do, try to make it look custom, not just the reg sealed box with 2 15s. Maybe do painted plexiglass, or just some other stuff I dunno there is a lot of room in the X to make it look tight. I think nice trucks always look better with custom systems..

slick- the plan is to have a box that is lifted 6 inches off the ground with a door underneath so that i can slide things through (skis primarily), i will have a large flamed plexiglass window that will highlight my 800a2, maybe the 4-channel maybe not, and whatever i go with for a cap (bat cap?), and some kind of a custom mounting (i promise to make it look good) for some 5 by 7s or 6 by 9s integrated into the box. to save money and time the box in general will be black carpeted (it will match the new black carpet in the rest of my truck too) but inside the plexiglass window its going to be exterior matching white. there will be no wires visibile whatsoever. now i just need to get all the money together for the parts.

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Originally posted by expo5.0
more questions-

can i mount a 6.5" coaxial with the basket out? what are the possible drawbacks etc. will it wreck the high end? what if its not in a sealed situation (like a door) what if it is in a sealed box?

well if you mount a coaxial speaker with the tweet pointin away, you will lose all that high end..... bass is pretty much omnidirectional, whereas all other frequencies are not so... you should have a little better low end response if the speaker is in a sealed box....but if the speaker is in the door the imaging isn't the best anyways so why worry about it?

--also isn't 3 ft3 a little large for a sealed enclosure for each sub?? maybe for all three, but my HX2 15 didn't even need 3ft^3 to sound good.....

--finally as for your door speakers, I am kind confused at what youre getting at in terms of mounting location?>?>:confused:

--oh yeah you must have some clue what youre doin, otherwise you wouldn't be thinkin this stuff up!! :p