ADVICE on how to hit 20Hz hard with my planned setup?

[Miguels]

2 12's does not have more cone area then a single 18. 2 15' do

[Mack187Murder]

2 12's does not have more cone area then a single 18. 2 15' do

Since 12+12 =24......I'm guessing total diameter of sub is not taken Into account and neither is the rubber. Just the cone? Am I near the mark

Also. Another question.

U guys say one 18 will need 8 cubes but it will pass in 6.5.

So if I put two fifteens in a 6.5 box. It wouldn't be big enough. But would the power of the two subs and the larger cone area make up for the smaller size of the box.

I know ideal to have bigger box. Just curious if two fifteens would win over the 18 in sheer power with ability to push more air. Even if the box wasn't ideal as big as u suggest?

[RainStryke]

Circle area of an 18" is 1018.2857 square inches, while two 12" is 905.1428 square inches.

The size of the box will depend on how much power you will be putting towards the subwoofer. If you have a single 18" and you are pushing 2K to it, you will need a bigger box to make it more efficient. If you can throw 4K at it, you can make the box a little smaller. It depends on the subwoofer you choose.

AMI Customs made a pretty informative post on optimum enclosures for SoundQubed subs:

http://www.stevemeadedesigns.com/board/topic/187809-hdc3-hdc4-optimum-enclosure-size/

When he says 5.5FT³ net. That means you have 5.5FT³ of open space in the box with the subwoofer in and not counting the space your port takes up.

[Mack187Murder]

Awsome brother. Uve r been really helpful. Definately like the price tag on a hdc4 18" and the fact I can get away just one. With the right box.

Gonna do some research on finding a good amp to match it with now. Thanks again guys

[reedal]

Circle area of an 18" is 1018.2857 square inches, while two 12" is 905.1428 square inches.

The size of the box will depend on how much power you will be putting towards the subwoofer. If you have a single 18" and you are pushing 2K to it, you will need a bigger box to make it more efficient. If you can throw 4K at it, you can make the box a little smaller. It depends on the subwoofer you choose.

AMI Customs made a pretty informative post on optimum enclosures for SoundQubed subs:

http://www.stevemeadedesigns.com/board/topic/187809-hdc3-hdc4-optimum-enclosure-size/

When he says 5.5FT³ net. That means you have 5.5FT³ of open space in the box with the subwoofer in and not counting the space your port takes up.

Who taught you the formula for circle area? Pi*r^2

Two twelves = 226.1946710584651

One 18 = 254.4690049407732

[Emmet]

If you're getting an 18 you need 8 cubes after displacement. You can get away with 6.5 but you're looking to getting low so tune low. And go big.

One thing. If you're not always playing edited music you won't like that setup.. For daily I prefer a box that plays everything . For demos and playing edited music then it might then your way might work. I really think you should think about it more before doing anything

If you're getting an 18 you need 8 cubes after displacement. You can get away with 6.5 but you're looking to getting low so tune low. And go big.

One thing. If you're not always playing edited music you won't like that setup.. For daily I prefer a box that plays everything . For demos and playing edited music then it might then your way might work. I really think you should think about it more before doing anything

I'm definately putting lots of thought into. That's why I'm asking for advice. I won't rush into this like I did buying a JL13W7 then being dissapointedm with the price.

I listen to a lot of drum an bass. Jungle. Dub step. And trap songs. Slayer. Six feet under. Shit like that. I'm at work but will post more in a bit. Thanks for the replys so far guys

You may be disappointed if you tune that low so. Most djs rarely like playing below a low E (~40hz) simply because they realise most small stereos won't be able to play any lower well. It's not unheard of, but chances are anything that drops below that was a mix made for a set where the dj knew the equipment he was using.

Anything sub 30hz not edited is rare.

[TaylorFade]

Circle area of an 18" is 1018.2857 square inches, while two 12" is 905.1428 square inches.

Wut?

An 18" is ~ 250. (2) 12's is ~ 225.

OP... have you ever even "heard" a system play 20hz? It's just mechanical noises.

Being ABLE to play down to 20hz is a lovely design goal. Designing specifically for it is a waste, IMO. But hey... it's your money and your system. Knock yourself out.

And ports don't "blow". You will get zero cooling benefits by directing your port at the amps.

[Mack187Murder]

Circle area of an 18" is 1018.2857 square inches, while two 12" is 905.1428 square inches.

Wut?

An 18" is ~ 250. (2) 12's is ~ 225.

OP... have you ever even "heard" a system play 20hz? It's just mechanical noises.

Being ABLE to play down to 20hz is a lovely design goal. Designing specifically for it is a waste, IMO. But hey... it's your money and your system. Knock yourself out.

And ports don't "blow". You will get zero cooling benefits by directing your port at the amps.

Hey this is your guys world and I'm just entering into it. I'm all for advice. The vent thing was just a theory. And as for trying to hit 20 Hz. I'm fairly sure rom what u guys have said. One 18 cube sub. With 4000 watts rms. In a 6.5 to 8 cube box. Tuned to around 33hz will have me close and hitting lots of lows happily in a daily. So we'll go with that. If I tuned to 31 hz or 32 hz. How much does each hz lower or higher affect the hz range above or below? If that makes sense.

[Mack187Murder]

I mean u guys say rune to 33 and I'll hit 25hz nicely. Should I leave it there or try and push down to 32 or 31. Or will that affect my highs too much

[MrSkippyJ]

31-33 is damn near about the same thing, plus it's not exact science anyway. If all your measurements and formulas say 33, once it's built and measured it could be 31 anyway.