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Discussion Starter #1
Can I build a dual 12 inch driver sub box with each driver on opposite sides of the box?
If I do would it have to be sealed in the middle or could it be an open chamber?

Thanks

Bop
 

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Discussion Starter #3
Is one way better than the other?
So one down and one forward would work as well?
Lastly what should I line the box with and should it be filled 50% with polyfill?

Thanks

Bop
 

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Well there really are no easy generic answers to your questions as it all depends on the drivers and the system design, but generally the "best" way to use dual drivers in the home is to have them mounted on opposite baffels in order to cancel vibrations. I have never seen a system with one downfiring and one forward facing, but sure, I suppose it could be done. Why do you want to do this? And as far as your enclosure construction techniques, it's up to you really. Many of my systems do not use damping material on the inside walls yet some of them do depending on their size. Polyfill use also really depends on the enclosure size and alignment, but I usually suggest about 50% fill (which would be 8 ounces per cubic foot of enclosure volume.)

What are your drivers, and what is your proposed system alingnment and net volume?
 

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Discussion Starter #5
Soundstream Rubicon R-12SQ series 1 (made in USA)
12 inch Sub with fantastic sound quality

Basket-Cast Alum diamond cut edge
Low Resonant Woven Carbon Fiber Cone
Progressive Slant butyl rubber surround
Pole Piece-Vented extended
Dual 4-layer/VC-BAELSV hybrid VC former
Progressive roll spider
Rubber boot Magnet cover
Terminals-push gold
Max 1200 watt
RMS 600 watt
Mag. Wgt. (oz) 120
V.C. Size (in.) 2.5
V.C. Imp 4Wx2
Fs (Hz) 29
Vas (Cu. Ft.) 2.075
Qms 4.397
Qes 0.52
Qts 0.465
Xmax (in.) 0.65 (16.5 mm)
SPL 86
Tune Freq. (Hz) 29
FREQ. RESPONSE (Hz) 25Hz-2k
Hole Dia. (in.) 11.25
Depth (in.) 8.125

Box sixe was to be 2.6 cu. ft. or 1.3 per side if baffled
Alingment I guess you mean would be one front and one in rear

Room is 20Lx14Wx9H.
Amp is QSC GX5 rated at 700 per channel @ 4ohms
Crossover is Behringer DCX2496 Pro
[email protected] 12 gauge connectors and cable.
 

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Elite Shackster
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I have never seen a system with one downfiring and one forward facing, but sure, I suppose it could be done.
M&K push/pull sub woofers work this way, and indeed my own sub is similar to this. The reason for it in this case, is that this particular type of sub requires one drivers motor to be outside of the box, and having it on the bottom is just the most practical way to hide the ugly bit. In honesty though, I couldn't see a specific reason to do this with both drivers mounted traditionally unless the box dimensions leant themselves to this as preference.

FWIW, the M&K style works as well as any other (or better if you ask me, in respect of sealed designs), and putting your drivers like that will work fine should you choose to do so.
 

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Elite Shackster
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Alingment I guess you mean would be one front and one in rear
This would be best for the cabinet. It doesnt really matter for the drivers. With one face holding the driver(s), as a driver pushes forward you get an equal opposite reaction from the box. The box is heavier so wont move as much as the driver, but you can still get some if the box isnt heavy enough and the driver is strong. By putting a second driver in the opposite face you cancel out this movement within the cabinet, generally making everything better. With no movement from the box, your also making sure there is no minor cancellation occurring so your getting the maximum output from your driver.
 

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Soundstream Rubicon? Man the last time I saw any of those was installing thim into a client's SUV. Are you using those because you happen to have them already or are you buying them? If the former, you are in for a challenge IMO, and if the later, don't do it as there are better options available for the price.
 

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Discussion Starter #10
I actually love the sound of them, I have ran them in my vehicles for 7 years. Both the 10,s and the 12,s
Last US made SQ soundstream sub and their best in my humble opinion.
The 12's with a qts of .465 perhaps I would be better off going ported.
The x-max of 16.5mm should be ok from what I am reading as well but you are the expert not me.

What say you oh learned one :)

Bop
 

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Sure. With two of those woofers in a 2.6 cuft sealed alignment you end up with an fb of about 48Hz, which is pretty typical for car audio but pretty high for home audio. This is what I mean by challenging, as with a high resonance it will likely sound boomy in your room and seem to lack really deep low bass output. But, if you must use them go for it, you might like them. Since you already own the drivers the only thing you have to lose is your time and a few bucks for the MDF. :)
 

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Discussion Starter #12
Well it sounds like I should go ported then as I think form what other have said I can get to 25hz to 22hz with them ported.
Thank you for all your input my friend.
What do you think about the ported option?

Bop
 

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Sure, in 2.6 cuft you can port it at 24Hz and get a relatively flat output curve. With your amp you can exceed Xmax at around 20Hz so a good steep subsonic filter will be needed.
 

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Discussion Starter #15
Would it be better on the drivers to tune to 21hz or 24hz since x-max is reached at 20hz. I would not likely run the amp at full power either. I went the 700 watt model instead of the 425 watt for headroom.
I see your point about not being able to over drive the driver though.
I am using the Behringer DCX2496 crossover so I can tailor the high pass (isnt the high pass a subsonic filter?) however I want I believe.
"You also get four different mono and stereo output operating modes, all with individual crossover filter types (Butterworth, Bessel and Linkwitz-Riley) with selectable roll-off characteristics from 6 to 48 dB/octave. The delays for all inputs and outputs are adjustable. This allows you to manually or automatically correct for room temperature, phase and arrival time differences."

Which crossover type and what is faster 6db or 48db I would assume 6db slope (if slope is the correct term.. hehe)
Is x-max limit lower in a bigger box?

Thanks again for all the help!!

Bop
 

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Discussion Starter #16
Does that software also say which port size and length I should run?
I was thinking 2 4in tubes flared to keep port velocity down to avoid port noise/chuffing.
 
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