Could somebody give me the advantage/disadvantages of a bandpass and a sealed box? I went to some of the links in the sticky but none of it really made sense.

 

bandpass=deep bass
sealed=hard/loud bass

 

thanks for replying, right now, I'm looking at the JL Audio CB212-W3 which the the bandpass with 2 12s. The catalog that I have said that bandpass systems are more ideal for low-power systems. What does this mean, and what kind of amp would I need to push these subs?

 

bandpass will give you a very loud and beep output. Say if you have 1 sub in a bandpass box (if contructed correctly) most people will think you have 2 subs.

Disadvantages to bandpass are tougher box building techniques. You will have to come up with several different calculations for the front chamber and rear chamber. You will also need to account for port lenght and such. You can always buy a box calculator and have it all figured out for you, but you will still need to build the box to the exact (and yes I mean EXACT specifications!).

Another disadvantage is that you have to be very carefull on how you power subs in a bandpass box. You can literally destroy a sub in a bandpass and not know it till its too late. The bandpass boxes also have to be bigger.

Sealed disadvantage, is that you will have to feed the same subs alot more power to get the same output volume. But you gain cone control and get better transient response. Sealed enclosures are smaller and are good for sound quality applications.

Before starting a war, I know that both box designs can be used for sound quality ... but in general if you want to be heard a block away with little power look at bandpass. If sound quality is more to you liking and still like to be heard a block away (you must have the amp to push them though) go to the sealed box.

 

thanks ispeed, so you are saying that the sound quality of a sealed box is better? Also, what do you mean by destroying the subs? How would you do that?

 

You see one of the great things about a sealed enclosure, is that it controls the cone movement. think of it like a suction against the cone. what happens with a sealed box is that when the cone moves out since the box is sealed the cone is limited to how far it can move (in theory). The resistance that is present allows you to give more power to a sub in a sealed box without risking blowing the sub.

In ported enclosures you don't have to feed the sub as much power to get the same output of a sealed enclosure. A bandpass box is just a more complicated ported enclosure. What that means is that the cone can move freely without the resistance present in the sealed enclosure. If you feed that sub too much power and really turn up the volume you can drive the sub hard enough that the cone can tear apart from the voice coil. Now why I say that you wouldn't hardly notice it in a bandpass enclosure is that you don't hear certain frequencies with bandpass. That's how it gets it's name. You are building a box that emphasizes a frequency range and other are "tuned" out. It is not really that simple, but in short you will more than likely not hear distortion from a bandpass unless you are really driving it hard. Now the downside to this is distortion is what kills a sub. Bringing it all together you are driving the subs to distort with too much power ... you don't know it b/c you can't really hear the distortion ... therefore you can destroy you subs without knowing it till its too late.

If I can find it tomorrow I will look for a real old issue of Car Audio and Electronics. In the issue I'm thinking of they go into great lengths to describe the advan. and disadvant. to all sorts of boxes ranging from sealed, ported, bandpass, isobaric, etc.