n0catchyname

I normally stick to single sub setups, and have never build a dual sub box - I've run one before, but was never happy with it. Right now, in my civic 4dr, I'm running a single 12" Cerwin Vega 124 (single 4ohm voice coil, 400Wrms on less than half of that power), and although I need to rebuild the box it's in, I'm quite happy with it (for what it is). Once I rebuild the box I'm sure I'll be even more happy with it. But I have another one laying around and got my hands on a 4-channel (bridgable @ 4ohms to probably put out around 150 actual Wrms x 2) so I was thinking I might try a dual setup @ ~twice the power of my single setup, just to bide my time until I can build in the Celica. I'm pretty sure it will overpower my deck powered speakers, but just for ***** and giggles.

Anyway, my question is given the box volume and tuning remains the same are there any advantages/disadvantages to running two 12"s in a shared chamber vs. seperate chambers. The program I use for box building gives me exact same results, which makes sense, but my thoughts are, the woofers would react differently in each scenario, due to the box size and air movement of the shared chamber vs. the seperate chambers. Am I wrong to think this? Being as I'm running them at around or less than 1/2 power, would it be better to run a shared chamber? I'm not exactly sure what the questions to ask would be, I guess just looking for some suggestions - other than building two boxes to see if there is a noticeable difference for myself - as to which one I should try, and, more importantly, why.

Father Yuli

iTrader: (17)

separate chambers is always better, just better loading that way. it sound better sq wise and even helps in spl some times. all about optimal loading.

godzilla1978

Someone is sure to correct me if i'm wrong but in order to gain 3Db(which is the smallest amount you will notice) you would either have to double your power, or double your surface area.

So in essence by halving your power and doubling your surface area, providing everything else is the same you will be exactly where you were with the one sub.

But I digress, assuming that there is enough internal volume for the 2 subs and that they are not mounted opposed, meaning they share the same baffle on a 180 degree plain. There will not be a differace between common chamber or separated. However I would note that 2 subs in there own chambers would be quite a bit larger over all than a common chamber box. Especially if it was a ported box, because they would both have to have there own port(takes up room that cannot be included in the internal volume) there would be more bracing inside(more space lost) and their more challenging to build and more costly as well.

The other possible problem is that most 4 channel amps don't have low pass cross overs which means you will not be able to filter out all of the frequency's above what subs like to play. It may not sound as good as before for that reason as well.

godzilla1978

yeah but on 150 watts do you think he's actually gonna hear that differance? Maybe on 500 or 1000. Also the internal volume of the box counts as well. The more volume the larger the differance.

Father Yuli

iTrader: (17)

initially i was going to say it wont matter (in his case), but he did ask the question and I felt i'd be ripping him off by not telling him what is really up. now he knows the truth.

n0catchyname

I am doubling power, right now I'm using a monoblock that rated 200Wrms (but I know due to amp quality I'm not getting that) @ 4ohm on a single sub, and I will be running dual 12"s on an amp rated at 210Wrms @ 4ohm (again low quality amp) per bridged channel. The box will be pretty much the same size (maybe slightly larger) as the single sub box, due to limited space. So in essence, I'm doubling both power and surface area and halving the box. Also, the amp does have LP, so I'm not worried that either.

I was planning on a dual port either way, and being as I'm running so little power, I'm not concerned with bracing. So really, the seperate chamber box will only be 3/4" wider than the shared.

I'm really not looking to do anything with this setup other than expand my box building knowledge. Like I said before, it will probably over power my speakers anyway, and I'm not looking to spend any money to upgrade my electrical or anything else, so I'll probably switch back to the single sub at a later date (if I don't have too much dimming or anything, probably switch back in the fall, earlier if I do). Just want to try it out since I have the equip laying around anyway, and don't want to build two boxes when I'm sure there are more knowledgable people to steer me in the right direction.

Thanks, this thread is less about my own install and more about learning (which is what the box building is about too). I guess I should've specified that to begin with.

godzilla1978

If your looking to simply gain building experience then I would suggest building the dual chambered box.

Keep in mind that if you are halving the internal volume be ready to loose alot of output from the subs. As yuli said before it's all about loading.In this case the single sub would be quite a bit louder.

Perhaps you should design a fancier single box with kerf ports or something like that. Or you could build multiple boxes with the single boxes with different port types or tuning that could be interchangeable. For me it's always been about maximizing performance while gaining experience at the same time!

Garvok

i'd go the dual chamber as well, BUT, dont halve the volume, spec it out, and do it up right, "L " ports otta give some nice tight sound.....or.......for poops and giggles......make 2 separate burp boxes, ie: very small.....with very big a$$ tunable aero ports.....sub up, port driver side....= loud.....hehhe sorta......they are vegas!!!
JK

3ni_07

dual chambered ftw!

fresh1

iTrader: (2)

I read an article that said that common chambers are better because of acoustic coupling.