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Discussion Starter #1
Hi all, i'm in the process of starting my first diy build....well actually, a friend of mine, not unknown in these parts (!) is going to put it all together for me. :)

Basically, i've bought a Behringer EP4000 to power it, and the only restrictions so far are that (owing to size constraints) the sub has to be sealed (to keep the size down). It works out at around 40 litres, and my basic question (apart from any advice along the way), is, what driver configuration would be the best?? Push pull, or dual opposed etc. Does it matter???

All i want, is the best bass i can get out of the restrictions i have.
The drivers are AE 12x for the upper bass slam, which is what i really like....the 'feel it in your chest' type bass.....but, obvously, i'm well up for it to dig deep too!!!

Any thoughts guys???
 

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i'd do dual subwoofers in opposite corners of the room, it helps with room modes and stereo subwoofers have to be heard to be enjoyed. i know you wanted small, but one in each of the front corners as sealed will probably yeild you the best in-room results. 40l is kinda small, but workable. 40l with 2 drivers is tiny.
 

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Discussion Starter #3
Ha ha, yeah it is....but that's what it modelled at....and i'm told that sealed with big power, can give good reults??!
 

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what kind of volume levels are you looking for?

remember sealed can go low with eq, but every little bit of EQ on low end will take away headroom.

These drivers won't handle the thermal power to get what youre thinking of getting out of them. theyre decent, don't get me wrong, but its a completely different beast you'd be looking for to pull that off.

Sealed 40l each, one on either side of the room is gonna be the best mix of depth and headroom.

Your benefit would be stereo subs will be just as loud as 2 in one box, but they'll extend deeper and have a flatter in room response with two. Plus less is more when it comes to equalization. And its not like your EP4000 can't handle one sub per channel. :p
 

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Elite Shackster
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The model works best with a volume of 50 litres. At full power it can output 100db @10hz, which will allow some room for a bit of eq. The system Q of this sub will be about .635, then with added wadding, this should give a nice balance of upper bass punch, and depth.

Prize, this sub will go at least as deep as a Monolith, so not to shabby, but should have significantly improved SQ.
 

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thanks moonfly, im at work so i don't have winisd to model the box, 40l seemed pretty close, but as usual, bigger is better :p
 

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Discussion Starter #7
Nah, unfortunately my little UK room won't allow for stereo subs due to what's already in the room, although it would be nice. I'll be coming from an SVS SB12+, and out and out SPL isn't my main concern.....i only watch films at -23 ish on my amp, so that's not the issue (for now!!!). Quality of bass is what i'm really after. I also like the ability of the bass to disappear as quickly as it appears.
 

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Elite Shackster
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I modelled a single dual driver sub, so probably still smaller than your thinking. Increasing cabinet size lowers system Q, and the preference in sound over here is not for it to be too low.
 

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im not an LLT enthusiast, i don't know what you're talking about ...:hsd: lol, Yeah i guess im overshooting a little bit, did you take driver volume into account? (could get you back up pretty close to where i was :p) anyways, yes, i agree. he's looking for chest thump and not subsonics. Dual 12s (not opposed i'm assuming) in the single 50l box would be great! i'd still go bigger if i could. its totally worth overshooting your build requirements as you won't be living there forever i'd assume and upgradeitis affects everyone lol.
 

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The model works best with a volume of 50 litres. At full power it can output 100db @10db, which will allow some room for a bit of eq. The system Q of this sub will be about .635, then with added wadding, this should give a nice balance of upper bass punch, and depth.
Agreed. This looks to be an excellent small cabinet design.
 

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just noticed moonfly you said 100db @ 10db... doesnt make sense, but im going to assume you meant 10hz. I'd go with the 50l box, aim slightly larger as youve got 2 drivers to account for, but not much larger. maybe 55 so that your not out so much volume. looks quite nice, and moonfly has experience with the AV line, so i'd expect him to be a great resource for this driver. Go for it and get back to us on what you think about it.
 

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Discussion Starter #12
Thanks Mike....as space is an issue, we're trying to work out the best possible compromise, and am open to all advice/opinions.
 

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Elite Shackster
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Your benefit would be stereo subs will be just as loud as 2 in one box, but they'll extend deeper and have a flatter in room response with two. Plus less is more when it comes to equalization. And its not like your EP4000 can't handle one sub per channel. :p
These drivers wont go any deeper separated than they would together. Like you say though, separating them would improve EQ but stacking, or combining maximises gain. This dual driver sub will be driven from one channel. By running a 2 ohm load, we can increase the wattage output by the single channel to a theoretical maximum of 2kw, which is perfect for these drivers. It would also leave a spare channel for that ever inviting second sub :D

im not an LLT enthusiast, i don't know what you're talking about ...:hsd: lol, Yeah i guess im overshooting a little bit, did you take driver volume into account? (could get you back up pretty close to where i was :p) anyways, yes, i agree. he's looking for chest thump and not subsonics. Dual 12s (not opposed i'm assuming) in the single 50l box would be great! i'd still go bigger if i could. its totally worth overshooting your build requirements as you won't be living there forever i'd assume and upgradeitis affects everyone lol.
We could go a little bigger, and Ive pondered going larger as internal volume could be reduced for experimentation using a block etc. System Q is important in sealed subs though, and depending on your requirements, your target Q will change. The .6xx target here is what I think will suit prize the best IMO.

just noticed moonfly you said 100db @ 10db... doesnt make sense, but im going to assume you meant 10hz. I'd go with the 50l box, aim slightly larger as youve got 2 drivers to account for, but not much larger. maybe 55 so that your not out so much volume. looks quite nice, and moonfly has experience with the AV line, so i'd expect him to be a great resource for this driver. Go for it and get back to us on what you think about it.
Oops, sorry, I'll have to fix that. Yes I meant @10hz. The 50 litre volume is what will be required after drivers and bracing is accounted for. A value of 3 litres per driver will be what is worked to, plus there will probably be a brace in there as well. I'm tempted to recommend the 55 litres though, it only lowers the Q by .02, and the model shows the drivers can handle the power.
 

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Elite Shackster
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By my calculations the box would be a 430 mm cube to have a net volume of 50 liters. That's tiny by my standards, and the performance should be excellent.
Bear in mind that a push/pull alignment requires one driver to be outside of the box. The best way to cover this up is to under sling it and build the box taller. The volume is small, but the cabinet would need to be a little larger than the volume suggests. A 450 cube will give a 55 litre volume, but the height would need to increase by about 250mm.
 

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Discussion Starter #16
By my calculations the box would be a 430 mm cube to have a net volume of 50 liters. That's tiny by my standards, and the performance should be excellent.
Yeah, that's roughly what we had.....a small footprint will suit its intended position though. I'm really hoping the performance is excellent. :T
 

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see, bigger is better, lol. i still dont like the idea of being smaller than 1 cu ft per 12 incher sealed. its... too small. lol. moonfly has definitely thought this through, i didnt realize he accounted for everything already.
 

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Discussion Starter #18
Well i think the 'perfect' size for the drivers comes out at around 55 litres, so still small, compared to some i've seen, but looking at the projected figures, it'll have some awesome performance. Still, bigger than my current svs sb12+, which, so far is the best 'in my room' bass i've heard to date, so i'm hoping for quite a step up in the quality stakes. :bigsmile:
 

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Ok, Ive built the basic cab and got the drivers in to do some testing. Final volume comes out at 57 litres, minus 3 ish for the driver, so about 54 litres. Just giving it a listen to now before I take it apart again and begin the finish. I'll give it a couple days of testing to ensure its spot on.

Anyway, pictures . . . . .

(I will add them later when I can upload, I'm getting an error ATM :hissyfit:)
 

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Moon, wasnt prize doing the build!? lol. I love how infectious playing with this stuff can be. What i meant when i was saying separating them is to give them each the same size of enclose (55l) not 55l combined! lol. Which would allow the driver to get a little lower without any eq.

Most people won't listen to these types of subs at their limits, so i figured if he could go lower without losing too much headroom, than he would be getting the best bang for the buck.
 
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