# Sealed or Bandpass?



## drice78 (Jun 2, 2004)

I am picking up a used 12" Kicker CompVR off my friend and was looking at some boxes at a local shop. I was told by the shop that I should use a bandpass for that sub. I have always used sealed boxes, so I have no experience with the bandpass or ported box of any kind. Anyone have any suggestion on whether sealed or another box design would be better?


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## sr20dem0n (Mar 19, 2003)

Depends on what you want

sealed - smallest, easiest to design and build (or cheapest to buy), not much low end.

ported - larger, harder to design and build, quite a bit louder for a given power (makes the sub more efficient), and depending on the tuning frequency it can play much flatter and dig MUCH lower than the same sub in a sealed box. Prefabs are generally tuned very high to give that "wow" effect, which screws up the freqency response, if you want good sound for music (read: not test tones) then you need to design and build your own.

bandpass - largest, hardest to design and build, very loud and very efficient, depending on the design, you can either get the sub to play a small range of frequencies (maybe 30-50hz) very flat and very well, with a natural rolloff on each end (no crossovers needed), or on the other hand you can design it to play a VERY narrow range of frequencies VERY loud (35-40hz for example), again with the natural rolloff. Unless it's built perfectly the response will generally be pretty crappy, and the response from prefab bandpass boxes will always be crappy, if you want a good bandpass you have to design and build it yourself.

I'm a fan of large sealed or low-tuned ported boxes, bandpass are just too hard to design and if it's not perfect it sounds like ass.


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## Jasper (Apr 2, 2004)

yeah. i like sealed. sealed will actually give you more output tho, not less. gotta be careful tho, reinforce the hell out of that box when you build it. my frist box blew itself apart (literally, the front plate stripped the screws out of the wood and fell off). ive got a 3cubic foot sealed (not divided) box with a pair of 12in Alpines wired in sequence. its *loud*


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## sr20dem0n (Mar 19, 2003)

Jasper said:


> yeah. i like sealed. sealed will actually give you more output tho, not less.



hmmm, guess that's why every SPL competitor in the country uses ported boxes....you might want to guess again


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## drice78 (Jun 2, 2004)

Looks like I am going to go sealed, either my own creation or buy one. Thanks for the quick speaker lesson :cheers:


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## Chicago Tony (Apr 15, 2003)

Go to Kicker's website. They have quite a few enclosures for the CVR. They will have different choices of sealed and vented boxes you can build. They have cutsheets and everything so you don't have to anything but read the sheet.





drice78 said:


> Looks like I am going to go sealed, either my own creation or buy one. Thanks for the quick speaker lesson :cheers:


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## Bumpin (Feb 18, 2003)

another thing about bandpass boxes is that they ware out your subs a lot faster than any other box out there and you will never know when your sub is goin bad until it takes a dump.


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## sr20dem0n (Mar 19, 2003)

How would they wear out your sub faster?

The current going through the coil is the same as in any other box, and the excursion is less than in any other box, which would mean less cone movement, less stress/strain on the suspension, and less wear...?

I'm not attacking you or anything, I've just never heard that before, and it doesn't seem to fit very well with the characteristics of a bandpass box.


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## Bumpin (Feb 18, 2003)

I'm just speaking from what i've seen happen to my friends subs. Now I will take your words into very high consideration cuz you do know your shit. Maybe they didnt have shit hooked up right or just somethin was wrong. But what you say does make sense. The only thing I dont understand is, how can it hit a lot harder in a bandpass box but have less excursion?


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## sr20dem0n (Mar 19, 2003)

Same as with a ported box, with a ported box as you approach the tuning frequency, the timing is just right where the air comes in the port as the cone moves in, and the air moves out of the port as the cone moves out. Obviously this means that as the cone moves in, the pressure inside the box rises a ton (since the box size is smaller with the cone in, and there's a lot of extra air because it's all sucking in the port), and as the cone moves out the pressure drops a ton. With such drastic high and low pressures, the sub behaves like it's in a tiny sealed box and it barely moves at all, so it's really not giving off much bass. On the other hand all that air moving in and out of the port _is_ sound (it's vibrating at the frequency the sub is playing after all), so it's giving off all the bass instead of the sub's cone itself.

It's interesting playing a frequency sweep while watching a ported sub (or any ported speaker for that matter), as the frequency drops the cone starts moving less and less even though it's getting louder, and then at the tuning frequency the sub is moving the least (it's just barely vibrating, while a rediculous amount of air is rushing in and out of the port). When playing a 30hz tone on the towers in my room you can literally feel the air from the port blowing by your legs from 10 feet away, meanwhile the cone is only moving maybe a quarter of an inch peak to peak (they're 8's btw, one in each tower).

A bandpass just takes this to another level, so the port is doing most of the work at all the frequencies the sub plays instead of just right around the tuning frequency.

And if you were wondering how SPL competitors can pump tens of thousands of watts into a single speaker during a competition and not bottom it out, it's because of this. They play right at or just above the tuning frequency so the sub's excursion is the least, then they pump thousands of watts into the speaker to get it moving to its full excursion (when you put the rated power into a ported speaker at the tuning frequency, it doesn't move anywhere CLOSE to its full excursion, like I said above it's just vibrating). Of course when the sub is playing at the tuning frequency AND moving to its full excursion it's rediculously loud, which is how they get the numbers they do. They can only play for a few seconds though or all that power they're feeding will melt the speaker's voice coil. A bandpass box would probably give them better numbers, the only problem is it takes up so much room that they could just get another ported sub and the pair would be louder than a single bandpass would anyway. Random bit of trivia for ya....


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## NotAnotherHonda (Aug 7, 2003)

ive used all 3 kinds of boxes, and the ported was by far the best for my subs


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## Ninety-Nine SE-L (May 5, 2002)

Well, I decided not to go with the Infinity Perfect. Instead, I'm going to get a JL W7 powered by the JL 500/1. I decided to have it professionally installed by a place here called StereoRama. Going to do a custom trunk. I know they know their stuff b/c they specialize in JL, but how exactly should a W7 be mounted?


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## SentraStyleEMW (Aug 15, 2002)

Ninety-Nine SE-L said:


> Well, I decided not to go with the Infinity Perfect. Instead, I'm going to get a JL W7 powered by the JL 500/1. I decided to have it professionally installed by a place here called StereoRama. Going to do a custom trunk. I know they know their stuff b/c they specialize in JL, but how exactly should a W7 be mounted?


Ummm...with screws...lol. Just kidding. But JL does recommend a 1" thick front baffle. What kind of price did they quote you for the custom trunk?


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## Ninety-Nine SE-L (May 5, 2002)

well, assuming I get all remaining parts from you (when I have the money and you got the ability), they said, about $3-400 for material and building. They're in Clearwater BTW.

My idea for the setup is
Show off the amps, sub, battery, and prolly cap with plexiglas. Maybe an SE-L theme. Black vinyl/leather look with red lighting. I want to still make my trunk as usable as possible as well. I'm gonna let them do their own theme with jus those rules.


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## sr20dem0n (Mar 19, 2003)

Ninety-Nine SE-L said:


> Well, I decided not to go with the Infinity Perfect. Instead, I'm going to get a JL W7 powered by the JL 500/1. I decided to have it professionally installed by a place here called StereoRama. Going to do a custom trunk. I know they know their stuff b/c they specialize in JL, but how exactly should a W7 be mounted?



Which model w7? If it's the 8 that will be fine, if it's the 10 it will be underpowered, and if it's the 12 or 13 it will be SEVERELY underpowered. Even the 1000/1 can't put out enough power to satisfy them, they're very very inefficient. You need 1500 watts to get the 13 moving decently, and atleast 12-1300 to get the 12 moving well. The 10 would like closer to 8-900, but the 500/1 puts out around 700, so if you have the 10 it should be alright.

And specializing in JL really doesn't mean anything at all, the Cartoys by my house specializes in JL and they don't know shit (atleast none of the people I've talked to do). I hope you have one very very powerful front stage (atleast 150x2 going to some very strong mids). The w7 is insanely picky about its box, and unless it's in a tiny sealed box (which lowers the efficiency even more) you're going to have to cross it at 50hz to keep it sounding good, which means your front stage is going to have to play loud down to 50hz to get any kind of blending going on (so the music doesn't just jump back and forth between the comps and the sub). If you can get the install and tuning right, it should sound very good.


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## nizzan4u2nv (Apr 14, 2004)

The 500/1 will not have suffient power for the w7.


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## Ninety-Nine SE-L (May 5, 2002)

well, I don't have EXTERMELY poweful mids. I assume I'm putting around 85watt to each front/rear on the 300/1. Maybe the W7 is overkill, but it's just about the only JL sub I really like. If I don't go with the W7, it'll prolly be back to the infinity perfect 12.1 or maybe an Xtant. I only want a single sub, and I only want to run the 500/1. I wouldn't say I'm obsessed with bass, but now that I had a taste, I want a sub back in my car.

Oh ya, and I would not go over the 10" if I did a W7, it'd either be the 8 or the 10.


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## sr20dem0n (Mar 19, 2003)

If you're dead set on the 500/1 and JL, I would look at getting a 12 or 13w6v2 personally.


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## Ninety-Nine SE-L (May 5, 2002)

well, I line the 500/1 b/c it fits perfectly next to the 300/4. I think a smaller W7, such as the 8 or 10 will do nicely, EMW said his place has done 2 10w7s on a single 1000/1, devide that setup by 2 and it's the same as 1 500/1 per 10w7. You said the 500/1 puts out closer to 700watt, I think that can power the 10 just fine.

I don't know about the w6v2, I've heard mixed reviews.


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## sr20dem0n (Mar 19, 2003)

Ninety-Nine SE-L said:


> well, I line the 500/1 b/c it fits perfectly next to the 300/4. I think a smaller W7, such as the 8 or 10 will do nicely, EMW said his place has done 2 10w7s on a single 1000/1, devide that setup by 2 and it's the same as 1 500/1 per 10w7. You said the 500/1 puts out closer to 700watt, I think that can power the 10 just fine.
> 
> I don't know about the w6v2, I've heard mixed reviews.



Like I said before, the w7 is not a flexible sub, if you get one you practically have to bend your life around the sub's needs, not the other way around. If you don't have a retarded front stage it will either not blend, not be able to get loud before the mids bottom out, it will sound muddy, or you'll have holes in your response (which end result you get depends on your tuning). People seem to think that just because it's JL's most expensive sub that it must be the best. Probably only 5% of the people who own a w7 really have a setup that the w7 would excel in, the other 95% of the people that own the w7 just have it because it's "the best" and they could really get just as good of performance out of any other sub out there, since the w7 really doesn't compliment the specific system that they have very well. The w6v2 is a much more flexible sub, and it's much more "forgiving" of a lacking front stage since it can still play high (80-100hz) and sound great.

Keep in mind, there's a reason why you see very very few w7s in the top competition-level SQ cars out there.

And about the power, sure you _can_ power a w7 with 500 watts, and sure someone might have a 1000/1 on a pair of 10w7s, but that doesn't mean it will power them well at all. I've seen someone who had a w7 on a 250/1, yes it would technically work, but it doesn't mean that there aren't some MUCH better choices out there for that price range and those power requirements.

I've heard many w7 setups, and personally even if they were half the price, I would still take several other subs over them. I don't have the room or the skills to make some ported door pods or kicks, so I don't really have the ability to make a front stage that would compliment a w7 well. Instead I need a sub that can play as high as 80hz and still sound good, which the w7 simply can't do unless you put it in a tiny sealed box and send it a buttload of power to make up for the loss in efficiency.


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