18" BTL N2 Box Design

[OuTLaWeD 110]

Alright, now that i can sit down and eexplain myself why i dont like your box ill point out a few things. When you make an enclosure that large you loose out on cone control and also as a sub gets broken in the spiders become softer and the surround aswell further making the sub at risk of mechanical failure and if for some chance you ever want to put more power to it you cant because you'll definitely throw the cone past it's limits and mess up your sub. If you choose to put more power on the sub and think you can shrink the enclosure easily by adding bracing or whatever then you have thrown off the tuning of the enclosure and you have to rebuild the port anyway. I always say do it right the first time and you'll never have to do it again. Building a large enclosure does flatten out the frequency curve and in return give you a more musical enclosure, but so will a smaller port and that doesnt have the potencial to damage anything. I would build the enclosure to 6 cubes net and give it around 80 square inches of port, that will be efficient and musical that way if you do decide t put more power on it later you won't htave to spend the time and money to build a new enclosure. I don't know your skill level so I put this out there as simple as I could and I'm a bit lit tonight, but if you have any questions I can probably answer them better tomorrow.

[Duran 387]

Alright, now that i can sit down and eexplain myself why i dont like your box ill point out a few things. When you make an enclosure that large you loose out on cone control and also as a sub gets broken in the spiders become softer and the surround aswell further making the sub at risk of mechanical failure and if for some chance you ever want to put more power to it you cant because you'll definitely throw the cone past it's limits and mess up your sub. If you choose to put more power on the sub and think you can shrink the enclosure easily by adding bracing or whatever then you have thrown off the tuning of the enclosure and you have to rebuild the port anyway. I always say do it right the first time and you'll never have to do it again. Building a large enclosure does flatten out the frequency curve and in return give you a more musical enclosure, but so will a smaller port and that doesnt have the potencial to damage anything. I would build the enclosure to 6 cubes net and give it around 80 square inches of port, that will be efficient and musical that way if you do decide t put more power on it later you won't htave to spend the time and money to build a new enclosure. I don't know your skill level so I put this out there as simple as I could and I'm a bit lit tonight, but if you have any questions I can probably answer them better tomorrow.

Taking away port area, if it is already near perfect, is not beneficial.

[OuTLaWeD 110]

Having less port volume will give you a more musical enclosure. In the easiest terms, it keeps back pressure on the sub allowing it to play a wider range. I'm not talking about making the port so small that you hear the port velocity I just saying a couple cu. in. less per cube of enclosure volume

[bassahaulic 155]

8 cubes net for a single 18? Way too big

2 18"s in 16^2 cubes with 360^2 of port. Tuned to 40Hz and plays within .4db from 28Hz-60Hz.

[bassahaulic 155]

Having less port volume will give you a more musical enclosure. In the easiest terms, it keeps back pressure on the sub allowing it to play a wider range. I'm not talking about making the port so small that you hear the port velocity I just saying a couple cu. in. less per cube of enclosure volume

That's retarded. Everything you just said was wrong.

I ad 20^2 of port per cube on my DD 95Z18 and it was the most musical setup I've ever had. And I've had enclosures with 12-16^2 of port per cube and they all sucked ass.

[Duran 387]

Having less port volume will give you a more musical enclosure. In the easiest terms, it keeps back pressure on the sub allowing it to play a wider range. I'm not talking about making the port so small that you hear the port velocity I just saying a couple cu. in. less per cube of enclosure volume

Internal volume has the largest impact on mechanical performance, the port area is completely dependent on woofer parameters, NOT enclosure size.

[OuTLaWeD 110]

Overall enclosure volume combined with port volume is what affects mechanical performance. If you have a port that's too big it won't allow the sub to load properly

[Duran 387]

Overall enclosure volume combined with port volume is what affects mechanical performance. If you have a port that's too big it won't allow the sub to load properly

Do you even know what the port does?

[OuTLaWeD 110]

Do this Duran, make an enclosure with an unbelievably huge port and another with a smaller than average port and test them side by side same power and everything and tell me what one had better sq

[OuTLaWeD 110]

You have to test the extremes to really see the picture

[ssh 924]

You have to test the extremes to really see the picture

But as long as the port isn't extremely huge then you can't tell a difference, and therefore it doesn't matter?

That's a one sided argument as well, say it was a small port and the vent speed was too high...

[OuTLaWeD 110]

You have to test the extremes to really see the picture

But as long as the port isn't extremely huge then you can't tell a difference, and therefore it doesn't matter?

That's a one sided argument as well, say it was a small port and the vent speed was too high...

There is an audible difference between a port that is just big enough to not hear the port velocity and a port that is 20 squares per cube. You will have better sq and more range in frequencies. It won't have quite as high of an spl number, but it's not like your gonna loose 3db with a smaller port either. It just makes a more musical enclosure

[bassahaulic 155]

Your retarded. Please stop posting. You clearly haven't ever actually been loud.

[Duran 387]

I'm not talking about an abnormally huge port, I'm talking about the minimum port area to be used when designing a port for a certain woofer. Do that, and you'll have a properly functioning vent, which can be used in the SPL lanes, and in SQ judging.

[OuTLaWeD 110]

I'm not talking about an abnormally huge port, I'm talking about the minimum port area to be used when designing a port for a certain woofer. Do that, and you'll have a properly functioning vent, which can be used in the SPL lanes, and in SQ judging.

Right, I think we meant the same thing, but worded differently. I see a 20 square per cube port too large and wouldn't sound as good as a 10 square per cube. And I definitely agree that enclosure size is the biggest thing when it comes to controlling a sub mechanically.

[OuTLaWeD 110]

Your retarded. Please stop posting. You clearly haven't ever actually been loud.

You sound like one of those idiots from the Suck My Di@& boards. Congrats

[trod2902 26]

As said earlier, box volume has nothing to do with port area, it all depends on the amount of air the driver displaces. So saying "20 sq in per cube" and such is not helping your argument as it appears you dont understand how to design a port around the drivers parameters.

[MikeMartel 64]

ChLL, your really trying to argue with a super mod? Genius idea, didnt know i was talking to the god of subwoofer enclosures sir. My mistake.

[bassahaulic 155]

Your retarded. Please stop posting. You clearly haven't ever actually been loud.

You sound like one of those idiots from the Suck My Di@& boards. Congrats

If you hear the samething there that you do here. Maybe its not the other users, ever think of that?

How loud are you anyway? What experience do you have that makes your ideas the best ever?

[altoncustomtech 773]

ChILL, I think you're a little too caught up on the "rule of thumb's" that are so widely found and used all too generally. The amount of port area a person uses in a design should be based on the parameters of the driver(s) being used. There are good formula's for determining the best port area for a given driver and even several calculators that make it easy to find as well. That being said, there are many many reasons to go higher or lower on port area in a given design, so even going with what is best for the driver according to it's specifications may not always be what a person should do.

IMO you've given good reasons as to why you thought 8 cubes was too large and why the port area was too much. However, because the fact is that EVERY design and build are different it's usually best to try a design based on the best compromises you can make and make adjustments from there. I do agree with you that it should be build right the first time, but using the same basic parameters for every build isn't a good practice. Sometimes it really does have to take a few tries to get it just right.

[An-i-no 86]

Damn...what happened to this thread

[OuTLaWeD 110]

ChLL, your really trying to argue with a super mod? Genius idea, didnt know i was talking to the god of subwoofer enclosures sir. My mistake.

No, No, you have it all wrong. I was never arguing with a Super Mod, I was arguing my opinion. He never disrespect me at anytime so I wouldn't show disrespect towards him. I am no "enclosure god" and never claimed to be. As I stated in the beginning of this thread that I was only giving my opinion and maybe trying to save you time,money,and maybe your sub in the future. If you took me wrong then I'm sorry, but I was just trying to help.

[MikeMartel 64]

Alrighty. Now that my thread is done being shit on, Thank you for all of your opinions.

[Shogen 325]

I'm not talking about an abnormally huge port, I'm talking about the minimum port area to be used when designing a port for a certain woofer. Do that, and you'll have a properly functioning vent, which can be used in the SPL lanes, and in SQ judging.

Right, I think we meant the same thing, but worded differently. I see a 20 square per cube port too large and wouldn't sound as good as a 10 square per cube. And I definitely agree that enclosure size is the biggest thing when it comes to controlling a sub mechanically.

Doesn't the subwoofer parameters have to do with how much port to use and power being applied? I've kinda lost it... but maybe I missed a posed that stated that...

[Shogen 325]

Alright, i made a rough sketch in google sketchup, not sized at all just random measurements but this is how i want it look, and the specifications i was thinking about using.

The port is partly external because i will be firing it through the rear deck of my car. Tell me what you guys think! (Still working on perfecting google sketchup)

Net volume ~ 8 cuft

Port Area = 144in²

Port Dimensions = 9 x 16 x 37 (length)

Tuning = 32hz

Sub will be facing up aswell as the port.

I think I can see it now... lol... looks insane to me but cool as shyt...!!!