DX12 and too much space?

mullet34

I recently bought a DX12 sub for a sealed box enclosure that has 1.25 cubic feet of free space. Now I see the recommended free space for the DX12 is .88 feet.

Any thoughts as to what to do? I can't return either the sub or the box.

sntnsupermen131

get the heigth and width of the box...multiply and figure out how long the box needs to be
get a hand saw and saw the rest of the box off...if you can use the original back...if not...go to local hardware store get enough 3/4" MDF to cover it, chaulk, wood glue, and ribbed nails or screws...when the back has been cut off...chaulk all the edges, cut the mdf to the right size, put the wood glue on the edge of the box where the back is going to go, have the box face down, back part you glued on up, let it set, then nail/screw it
you want to let it set so it wont move when you nail/screw it down
then get the same color carpet...carpet it
silicon the inside of the back panel
if the box is plastic...you bought a cheap **** box anyway and/or you dont feel like doing that....really the only thing you can do is ebay the box and get another
-Cody

mullet34

That's a little too much work, especially since I don't think I could cut off the right amount from the side without interfering with the round sub cutout. I was thinking more along the lines of putting dampening material inside the box to absorb space.

This box is for my boat, so I'm not all that concerened about the space differential, unless this is going to damage the sub.

PoweredByDodge

too big of a box will fk up that sub.

u're nearly 0.4 cubic feet too large.

to give u an idea of what you'd have to "stuff" that box with...

you'd have to get 4" x 4" wooden fence posts....

cut 3 pieces that were 1 foot long... then place all three of those 4 x 4 x 12 " pieces in the box -- so u had a piece that was 4 x 12 x 12 --- that's a whole lotta wood dude. and that's only 0.33 cubic feet.


you're much better off sawing 4" off the back of the box assuming the box is like 12" by 12" in back.


that or buy a new box. you'll jack up that sub otherwise.


actually i take that back, if you're only gonna put 200 watts on it and not drive it hard at all .. you'll be fine, but if you intend to put 275 / 300 / 400 watts on it and use it to even remotely near its full potential, you'll be doing it an injustice if u dont hack the back smaller.

mullet34

Thanks PBD. I actually have a ton of fence posts in the backyard that I could use.

I will be using a Soundstream amp to push about 150 through it, so there's not much chance of overpowering it.

sntnsupermen131

make sure the posts are secured in the box...you dont want them sliding and hitting the sub...150 for that sub?
thats weak...but whatever floats your boat
-Cody

mullet34

150 for that sub?

Gimme a break.....why on earth do you think you need to push 200+ watts through a sub to get decent sound?

This is for my boat and I don't feel the need to sound like a ghettoed out lowrider when I'm wakeboarding. Not everyone on the lake appreciates my music, just like I don't appreciate the 15 - 20 boats out there that have ghetto systems tossed in them by spoiled rich kids who think they need to vibrate other boats in order to get respect.

PoweredByDodge

mullet, i dont think thats what cody was trying to say...

i understand where you're coming from, but the thing is that that particular sub is pretty low efficiency --- like 86 db's. were it a 90 db sub i'd say "sure 150-200 will get that plenty loud for a normal size car"

however take into acct two things here... 1 the low efficiency of the sub... and 2 the fact that you're on a boat in open space -- inside a car, 150 watts may be like a 5 on the loud scale... in open air that sub with 150w will probably only be like a 1 or a 2... factor in the noise of the motor, other boats, and the lake / river / whathaveyou, it may be inaudible.

i'm sure that's all cody was tryin to get across, and it certainly is the only "objection" i have to putting half power on the sub.

i run like 230 to DX10's in my girlfriend's car, and it's far from "ghetto rumbling" -- its actually about the lowest u can go on the sub and get it to perform well with classic rock or other such stuff --- obviously with rap music any sub is gonna pump out... its the more subtle music that gives ya trouble.

the sub really starts to show its true colors around 300 - 350.

having owned 8 DX series subs, i can tell you that 150 (In car) will just about make the speaker "move", barely... and you may end up burning it up from trying to dump clipped power into it in an effort to juice up the performance.

its not the amp's fault, not your fault, not even the speaker's fault... its just a mismatch.

there are many subs that are 92 or so db rated efficiency out there... they've also got much lighter cones, so 150w will move them much better... if the cone mass of sub A is twice that of sub B, then sub B will probably be a good deal louder than sub A... factor in that sub B is made to work "best" on 150 - 200 watts, while sub A is built for 400 watts, and you've got a situation where subs B will sound fine and sub A may not even produce audible sound.

throw that on a boat and everything gets worse.

see what i'm sayin?

this normally isn't my style to say this, but you may want to put that sub in a ported box.

the DX series are not built for ported application, suspension isn't right, however, because you'll be using under half the usual RMS power, i dont think you're going to stress it enough to cause any trouble, and the sub should survive quite well.

also, when u port it, it will give increased sensitivity in usually that 40 to 70 hertz range... peaking around 50 or 60... those aren't exact numbers but its ballpark-ish.

either way, what it will do is increase the sensitivity of the sub to a point where 150 watts will probably move it well enough to give u decent audible response in teh boat environment, which is what you want it to do!

also, and you're gonna like this one... if the sealed box volume of a sub is about 0.8, then the ported is usually somewhere in that 1.3 to 1.5 range... this is not always true, but its a common thing.

so... you've got a 0.88 sub in a 1.25 box... well... now you dont have to cut your box up!!

dont stuff it, dont do anything to it... just go to any local audio store and ask for a port tube... looks like a piece of PVC pipe with a small flange at the top, this is so that when u stick it in the box, it stays there.

if you cant find one of those... any local home store will have PVC pipe... u can use that in a pinch and just silicone the **** out of the point where the pipe meets the box and let it dry... once its hard it wont go anywhere.

if you do this, you'll have to figure out what diameter pipe you'll need (usually either 1" / 2" / or 3" or something in between... i'm guessing 2" or around that) and also length, how long of a piece of pipe u shove through that hole.

once u get the dookey little piece of pipe u just cut that hole and jam it in there and call it a day... i believe that'll do absolute wonders for your sub on the power you have stated, and that it will solve your box size problems without minimal work involved (take u 20 minutes tops dude).

as far as port specs (diameter / length) you can probably use the reccomendations for the polk GNX and call it a day... i'll ask around and see what i can find out.

mullet34

I really appreciate the reply and clarification, PDB. I didn't mean to offend anyone.

It's a moot point now. I bought the 12" thorugh an eBay auction. The sub was described as "brand new" and "mint condition". Just got it tonight. What a joke. The sub is scratched up all over, the sides are bent and the cone is seperated from the coil.

This jackass I bought from will be refunding my money or I will be making a drive to college station with a few guns.

So I guess I need a different sub, one that 's good with 1.25 cubic feet of air and comfortable running at 150 watts. Any suggestions?

sntnsupermen131

college station tx?
never do business with an aggie!
how much can you spend for the sub?
and what brand is your amp?
and the amp is 150watts x1 @ 4 ohms right?
-Cody

PoweredByDodge

cody -- he's got a soundstream amp -- soundstream is actually pretty good -- their rubicon series is powerful as hell. but all around they make an amp about quality of an mtx / RF but they do more class AB stuff than D.

mullet, not to promote violence, but have u ever heard the term "skull ****"? lmfao.... well that is what i'd do to that **** who sold you the bad sub... damn jerk.

anywho... 1.25 cubes and 150 @ 4 ohms... lets see here.

i'm not gonna throw anything i really like at you because i think it goes without saying you're lookin for something reasonably priced...

high efficiency, 1.25 cubes, 150 - 200 rms rating... that leaves us with:

1- JBL GT120: 250w rms / 93 db efficiency / 1.0 recomended box size, but since u're goin a little under the rms, 1.25 would be fine, just dont use any polyfill in the box. $99 bucks at crutchfield, about 75 on ebay.

2- Alpine SWS1241: 200w rms / 89 db efficiency / 0.85 to 1.5 sealed so 1.25 is smack in the middle of that and will do fine. $129 at Crutchfield, cheaper at www.ikesound.com or ebay ($95 @ ikesound)

3- Polk GNX 12": 175 w rms / 93 db efficiency / 1.25 cubes reccomended. $160 @ crutchfield... cheaper on ebay -- wayy cheaper. sub is worth about 90 bucks, dont pay more than 100 if u go with it. my only problem with this one is it has a VERY flimsy cone. a light cone is good for your application, but flimsy is another story.

4- Infinity Reference 12w30: 300 w rms / 92 db efficiency / 1.25 box volume -- $75 on sale at sounddomain.com

5- Phoenix Gold Tantrum 12": 300w rms / 90.1 db efficiency / 1.20 cubic foot box --- $85 on closeout at sounddomain.com


Based on price, quality of the speaker(durability / chance of breakdown), and how i think its gonna sound, my choices out of those would be in this order... best first.

1- PG Tantrum @ 85 bucks www.sounddomain.com
2- Alpine Type S @ $95 www.ikesound.com
3- JBL GT120 @ 69 www.sounddomain.com
4- Infinity Ref @ 75 www.sounddomain.com
5- Polk GNX @ 165 www.crutchfield.com

all of the above subs have butyl rubber surrounds and decently constructed cone materials so that you're not gonna damage them with sunlight or any little water that might get around them in the boat.

I think the PG is the way to go... dont be tricked by price, it retailed at about 140 or so before it went on sale.

sntnsupermen131

im not sure about the other subs...but ive heard the alpine before...and i really liked it...and im not easily pleased...but for a medium power sub...it hits heard and maintains good sound quality for the price
-Cody

PoweredByDodge

just got the system in the caddy running -- been waitin on the head unit -- and yes i installed a hed unit at 1-30 in the morning -- i dont care, i'm marginally insane.

i couldn't run it at full power (note - 130 am), but from what i can tell so far, those PG Tantrum 8's i loaded in the back deck slam like a drunk girl on prom night...

tight, loud, not as deep as a 10/12, but plenty deep enough...

for a 180w rms per sub in a huge **** car like an old caddy they've impressing the hell out of me.

full verdict on the system in the morning when i can bump bump bump away!