my custome build bandpass box.

[wicked]

in a conventional, sealed or ported box, low frequency extension is controlled and limited by the interaction of the speaker and the enclosure, but high frequency response is a result of the speaker's natural frequency capabilitiys unless limited by a crossover.
bandpass ported front chamber acts as a low pass filter which acoustically limits the high frequency response of the subwoofer. no high frequency will pass into the listening environment, thus delivering deeper and lower bass tone, with or without a crossover. granted, the bandpass design is very complex to build, but if done correctly, taking the same sub side by side on a tuned ported box and a tuned bandpass box, theire is no way a ported box can deliver deeper and lower bass. its just not possible. the hole idea and design of a bandpass is just that, delivering greater low frequency, efficiency and deep bass extension. this is not at all possible in conventional designs of equal size.
im not picking one box design over another. all designs yield their own advantages and disadvantages. its just what the listener wants and leans more towards. no one enclosure is better than another.
breakdown:
sealed- deep, precise bass
ported- forcefull bass
bandpass-maximum slam
more info at http://crutchfield.custhelp.com/cgi-bin/crutchfield.cfg/php/enduser/std_adp.php?p_faqid=2967
last, just a few high end manufactures using bandpass or reflex designs for home theater subs. bose, KEF, AR, and canton. i guess in the end, to each his own. i have been building sub boxes for about seven years , i dont consider myself an ameture and i have yet to hear a ported box deliver deeper bass than a bandpass. more acurate, yes, but not lower and deeper. i would still like some options on good bookshelf speakers on a budget of about $800 dollars. thanks and hit me up with any other info.

my home theater room.http://www.flickr.com/photos/wicked_photos/

 

[no. 5]

last, just a few high end manufactures using bandpass or reflex designs for home theater subs. bose, KEF, AR, and canton.

*ahem*

Out of curiosity, have you done a frequency response sweep, just to see (or hear, rather ) what the low frequency extension of your system is?

 

[annunaki]

I don't think he has.

No offense wicked, but I will go so far as to say you are incorrect here. A Bandpass enclosure cannot play deeper unless it is tuned deeper than a comparable ported enclosure. There is no way around it. It is dictated by physics.

You are correct in saying that a bandpass rolls off the high frequencies. A ported or sealed enclosure would require a crossover (as should any bandpass though it would not require as steep a slope). However, it does not make the system play deeper, it just makes it more efficient.

The ONLY advantage of a bandpass type enclosure is increased efficiency through out the pass band. They cannot play deeper unless tuned deeper. Basically, they play louder but at a cost of accuracy. That is it. Designing a bandpass enclosure capable of playing as low as a ported enclosure (say tuned to 18hz-20hz) would be a pain, not to mention about 2x the size of an equally tuned ported enclosure. The increase in output over a ported enclosure would probably only be about 1db-2db potentially more depending upon how narrow the pass band were designed.

What you are hearing when listening to a ported or sealed woofer next to a bandpass is the difference in loudness. When a system is playing 2db louder than another it will sound "deeper" because it is playing louder. The fact is, a ported or sealed enclosure will almost always deliver a smoother, flatter response curve from 20hz-80hz than a bandpass enclosure.

A bandpass can equal the flat smooth response (of a low tuned ported enclosure) but not without the hassle of an extremely large enclosure and tediousness of trying to get the response spot on. IF this can be done correctly, a bandpass would simply yield higher efficiency not deeper response. It would simply be a bit louder, in theory. The issue here is that bandpass enclosures also begin to lose their efficiency gains the wider their pass band becomes. So, that being said, a properly designed bandpass with response from 20hz-80hz would not yield much advantage in efficiency over a low tuned ported enclosure.

As you can see for the reasons stated above, much of the subwoofer community has abandoned the bandpass enclosure. Coupled with advances in woofer design and the size of the enclosures, bandpass systems are beginning to be obsolete. Sure, there will still be applications where it may be useful (concerts, sound reinforcement) but for the most part, they simply don't work well for the home theater/audio environment.