I've decided if I can keep from having to make a wall to fit them both I would rather go that route. I should be getting my truck back here shortly. Then I can start on the box for the 2 18"s. They'll be pushed by an Orion 2500D. I had a plan made up to do a 4th order box in a wall, but I would rather not do a wall if I can get away with it.

What would be the smallest sealed box I could do per sub?

Seems to me that anything 4cubes or more per sub will suffice.

I thought i'd ask, cause I'll have (after sub & brace displacment)7.2 cubes net (3.6 each). I was wondering if that would be enough, maybe add some polyfill.

I think you'll be fine with that.Probably wont be that flat,maybe a little peaky around 45hz area.You can get away with it sealed.I would still be ok with it,but ultimately you wont know till you try it.What kind of vehicle are we talking about?

Almost forgot,I never have sucess with poly fill.This is my opinion but it always has the opposite effect for me I don't like it.Box sounds bigger to me without it,so try it both ways and do what sounds best to you cause that's what matters right?

Sealed is what i'm going for both 18"s. It'll be in a 92' s10 4dr blazer.

Given the typical T/S specs on SS's site, both the d2 and d4 would be better sealed than vented. The d4 prefers a larger box than the d2 but both should do fine in 7.2 cubes. By my calculations a pair of d2's in 7.2 will have a -3db of ~35hz and a Q of ~.88, d4 = -3db of ~34hz and a Q of ~.95. You should see a slight gain in efficiency and power handling but with slightly peakier response. IMO, polyfill will probably not make a noticeable difference.

Edited May 20, 200718 yr by You Ham-fisted Cluck!

Given the typical T/S specs on SS's site, both the d2 and d4 would be better sealed than vented. The d4 prefers a larger box than the d2 but both should do fine in 7.2 cubes. By my calculations a pair of d2's in 7.2 will have a -3db of ~35hz and a Q of ~.88, d4 = -3db of ~34hz and a Q of ~.95. You should see a slight gain in efficiency and power handling but with slightly peakier response. IMO, polyfill will probably not make a noticeable difference.

Thank you. They are both D2's. Would I be better off putting them both in one sealed box, or put a divider to separate them? Normally I've put subs in one box, and just braced it well. Thx again for the help guys, Vic.

Would I be better off putting them both in one sealed box, or put a divider to separate them?

I would only do this if my subs were getting power from two different sources (i.e. 2 amps) or receiving a stereo signal (instead mono or summed). Otherwise you will not notice a difference.

Sounds good. So, 7.2 cubes (combined enclosure) for 2 18" rl-p's will be fine running off of an Orion 2500D. Thats what I needed to find out. Thx for all the help.

Do those amps come with birth sheets? I know it's 2006 cea compliant so you'll be recieving its rated power anyway,but I see a problem.You said they were d2s each.That means you can only run 2ohms safely w/both subs which is what 600wrms total or 300 per sub.I don't believe that amp is .5 ohm stable.You need to get another 1200d and run a sub to its own amp in parallel for your 1ohm 1200wrms per sub & amp combo 2400wrms total.Right now one sub to the amp for quick attack and impact.Two subs to that amp is going to sound slow,weak,booming.What I mean is it wont keep up with your highs cause it wont have the punch that proper power gives it.Hope you understand what I said.The only posible way for one of those amps is .5ohm but I dont know if it would handle it.I wouldn't try myself.

Right now one sub to the amp for quick attack and impact.Two subs to that amp is going to sound slow,weak,booming.What I mean is it wont keep up with your highs cause it wont have the punch that proper power gives it.Hope you understand what I said.

Why would you say that one amp to those two subs is going to make it sound slow, weak, and booming? The amout of power to the sub will not affect its sound reproduction capabilities, just its output capabilities.

IIRC keeping the same power but doubling the effective cone area theoretically yields a 3dB increase in output potentional too.

Do those amps come with birth sheets? I know it's 2006 cea compliant so you'll be recieving its rated power anyway,but I see a problem.You said they were d2s each.That means you can only run 2ohms safely w/both subs which is what 600wrms total or 300 per sub.I don't believe that amp is .5 ohm stable.You need to get another 1200d and run a sub to its own amp in parallel for your 1ohm 1200wrms per sub & amp combo 2400wrms total.Right now one sub to the amp for quick attack and impact.Two subs to that amp is going to sound slow,weak,booming.What I mean is it wont keep up with your highs cause it wont have the punch that proper power gives it.Hope you understand what I said.The only posible way for one of those amps is .5ohm but I dont know if it would handle it.I wouldn't try myself.

The 2500d has the following specs as far as I can tell:

1 X 1200 @ 4 Ohm

1 X 1700 @ 2 Ohm

1 X 2500 @ 1 Ohm

Not sure where you got the 600w @ 2ohm spec from.

Do those amps come with birth sheets? I know it's 2006 cea compliant so you'll be recieving its rated power anyway,but I see a problem.You said they were d2s each.That means you can only run 2ohms safely w/both subs which is what 600wrms total or 300 per sub.I don't believe that amp is .5 ohm stable.You need to get another 1200d and run a sub to its own amp in parallel for your 1ohm 1200wrms per sub & amp combo 2400wrms total.Right now one sub to the amp for quick attack and impact.Two subs to that amp is going to sound slow,weak,booming.What I mean is it wont keep up with your highs cause it wont have the punch that proper power gives it.Hope you understand what I said.The only posible way for one of those amps is .5ohm but I dont know if it would handle it.I wouldn't try myself.

The 2500d has the following specs as far as I can tell:

1 X 1200 @ 4 Ohm

1 X 1700 @ 2 Ohm

1 X 2500 @ 1 Ohm

Not sure where you got the 600w @ 2ohm spec from.

+1, and with the right electrical system (which I have) the 2500d is very cappable of running at .5ohms.

Do those amps come with birth sheets? I know it's 2006 cea compliant so you'll be recieving its rated power anyway,but I see a problem.You said they were d2s each.That means you can only run 2ohms safely w/both subs which is what 600wrms total or 300 per sub.I don't believe that amp is .5 ohm stable.You need to get another 1200d and run a sub to its own amp in parallel for your 1ohm 1200wrms per sub & amp combo 2400wrms total.Right now one sub to the amp for quick attack and impact.Two subs to that amp is going to sound slow,weak,booming.What I mean is it wont keep up with your highs cause it wont have the punch that proper power gives it.Hope you understand what I said.The only posible way for one of those amps is .5ohm but I dont know if it would handle it.I wouldn't try myself.

The 2500d has the following specs as far as I can tell:

1 X 1200 @ 4 Ohm

1 X 1700 @ 2 Ohm

1 X 2500 @ 1 Ohm

Not sure where you got the 600w @ 2ohm spec from.

earth is probably making the assumption that this is a new orion 2500d, one that is rated at PEAK power. sometime in the last year or so, orion has changed over to peak ratings, the new "2500d" is the 5000d. so that would make the new 2500d a 1250wrms amp, or 600x1@2ohm.

and ox is correct. the older 2500d can indeed run at .5 all day long. mine certainly did, and that's with a factory electrical system!

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

My bad I thouht we were talking about the 07 model were I would be correct.So u have the older model then right?For TOPGUN I said that because it would be like runnig those subs off of a head units built in power vs. an amp that matches the rms of the sub.That's the difference in sound I was trying to bring across.Back in the day when I used to run 50wrms to each of two 12s then later upgrade the amp for one that puts out 200wrms to each 12,that was a huge output difference.Hope this clears things up I assumed that he was using the 07 model so I appologize for that mixup.

No problem. I probably should've made it a little clear as to which one I was useing.

Where are you trying to put the box? Behind the rear seat, removeing rear seat, ect..? I ask cus i have a 1st gen 2dr 2wd blazer and i've had a box in mine that was around 9 cubes and it fit behind the rear seat and was only a couple inches above the window line. In a 4dr you have an extra 6 inches to play with.

I also used threaded rod to brace without taking up much space. If your removeing or folding the rear seat down then you'll have more than enough sealed or ported. I can fit 20-21 cubes in my 2dr this way and be an inch or so above the window line and still have room for 2 to 4 extra batteries, a hiding spot for my alarm backup battery and a small (and i do mean small) extra compartment for hiding/storing little things like wiring, ect..