Sub enclosures

[i_a_n112784]

I'm building my own sub box because I don't want one of the big, heavy, often ugly ones you find at stores. My question is, for a bandpass box, about how large should the sealed area be for a 8" woofer?

[GSteg]

depends on the subwoofer and your goal. i wouldn't make a bandpass as it takes too much time and u can EASILY make mistakes.

[i_a_n112784]

I'm just talking about a smaller bandpass, I don't need half my trunk taken up. Also, I've heard that they are the best kind of box for sound quality (forgetting about the space issue). I was also thinking bandpass because the woofer is protected against objects possibly poking it because I may still want to use some of my trunk.

[sparq]

Originally Posted by i_a_n112784

I'm just talking about a smaller bandpass, I don't need half my trunk taken up. Also, I've heard that they are the best kind of box for sound quality (forgetting about the space issue). I was also thinking bandpass because the woofer is protected against objects possibly poking it because I may still want to use some of my trunk.

Nope wrong - bandpass is the absolute WORST bos for sound quality. You want a SEALED box!!!!!! And to protect the woofer, you just get a woofer grill - problem solved.

Your better off buying an already made box - because no matter how "ugly" it may be, for an amatuer to build a box ... I can guarentee it will look better then what you are about to build.

[k67p67]

Originally Posted by sparq

Nope wrong - bandpass is the absolute WORST bos for sound quality. You want a SEALED box!!!!!!

Where did you pull that out of your @ss??? A properly constructed bandpass enclosure is great for SQ. Problem is that they are not at all forgiving. If your volume calculations are off even slightly, the sub will not perform nearly as well as it should.
And for ANYONE who suggest buying a generic enclosure rather than building one to mfg's specs...get a clue. Different drivers are meant for different types and volumes of enclosures and are better suited for different types of usage. You can't use the cookie cutter approach to enclosures.

[dirty91crx]

the bandpass box if properly tunes is great for sound quality on the lower notes.....the sealed box is best for all types of music....all out spl you would want to go with the ported box. as far as banpass boxes are concerned.....do you guys remmember when planet audio came out with the tri-chamber bandpass? that was one of the best bandpass box i have ever heard that was made by the manufacturer.

[sparq]

Dear k67p67,

Oh so I pulled it out of my ass? Hahaha, where did you pull yours from - your sand infested vagina? There are literally HUNDEREDS of enclosures available on the market - all you do is go match up the box to your woofers requirements.... wow how hard is that. Your sub says you need 1.25 cubic feet - you go buy a subwoofer box that provides 1.25 cubic feet... wow isnt that rocket science?

What type of system should I use?
As with home audio systems, there are five basic types of subwoofers systems that can be used: sealed, ported, bandpass, passive radiator and transmission line systems. However, the best type of subwoofer system for in-car use is usually the sealed system, as (1) the box size requirements are usually the lowest for sealed systems, and (2) the 12dB/oct rolloff of a sealed system is a perfect match for the free 12dB/octave rise in response below 60~80 Hz that you get in a car because of cabin gain. The combination of these two conditions typically produces a frequency response curve that remains flat almost to DC (0 Hz). Most sealed systems designed for car audio use employ a Qtc of 0.8-0.9, to minimize box size requirements and maximize power handling, while still providing acceptable results.

http://www.diysubwoofers.org/caraudio.htm


First off, the original poster said he did not want a BIG HEAVY box, last time I checked, your bandpass systems are going to be the biggest, and thus HEAVIEST of the subwoofer box choices.

Second off, hes asking how large the sealed area should be on his 8" woofer - yet doesn't mention what woofer he will be using. You are offering a "cookie cutter" suggestion yourself, not all woofers play good in bandpass boxes.

Third off, if he is asking how much space is required for his 8" woofer which we dont know what model it is - its pretty safe to say hes going to have NO idea how to properly build, or tune a bandpass system -- which defeats the whole purpose of even having a bandpass system. So yes, even in a worst case scenario that he goes out and purchases a "cookie cutter" box - I can almost guarentee it will still sound better then whatever he makes himself.

[k67p67]

Originally Posted by sparq

First off, the original poster said he did not want a BIG HEAVY box, last time I checked, your bandpass systems are going to be the biggest, and thus HEAVIEST of the subwoofer box choices.

Second off, hes asking how large the sealed area should be on his 8" woofer - yet doesn't mention what woofer he will be using. You are offering a "cookie cutter" suggestion yourself, not all woofers play good in bandpass boxes.

Third off, if he is asking how much space is required for his 8" woofer which we dont know what model it is - its pretty safe to say hes going to have NO idea how to properly build, or tune a bandpass system -- which defeats the whole purpose of even having a bandpass system. So yes, even in a worst case scenario that he goes out and purchases a "cookie cutter" box - I can almost guarentee it will still sound better then whatever he makes himself.

True bandpass enclosures are likely to be the largest types of enclosure choices for any given driver. However, I never suggested that he build a bandpass enclosure. He's a noob and should definitely stay away from building anything that complex. True, not all subs will perform well in a BP enclosure, never said they would. Your comment was (and I am quoting) "
Nope wrong - bandpass is the absolute WORST bos for sound quality. You want a SEALED box!!!!!!. That is inaccurate.
As for whatever he decides to build being better or worse than a prefab box, maybe, maybe not. A sealed box is just 6 pieces of wood with a couple of holes in them. Not rocket science either. People who buy prefab enclosures usually don't pay attention to the GIV of the box. They go out and buy something cheap that will fit in their trunk. And most of that stuff at your local stereo shop is CRAP (poor construction, low grade materials, no bracing, etc.).

[PaulD]

bandpass enclosures have lots of problems that get in the way of good quality sound. Higher order anything in the real world is just gonna be like that. The one good thing about a bandpass enclosure is that it is very efficient (loud) in the band pass frequencies. Just remember, you are dealing with physics here - and you get no free lunches - everything is a trade-off

[GSteg]

bandpass were originally built for theater used back in the 1920's or 1930's. carefully designed bandpass box can get you a flat frequency response from X freq. to Y freq without any use of EQ.

What type of system should I use?
As with home audio systems, there are five basic types of subwoofers systems that can be used: sealed, ported, bandpass, passive radiator and transmission line systems. However, the best type of subwoofer system for in-car use is usually the sealed system, as (1) the box size requirements are usually the lowest for sealed systems, and (2) the 12dB/oct rolloff of a sealed system is a perfect match for the free 12dB/octave rise in response below 60~80 Hz that you get in a car because of cabin gain. The combination of these two conditions typically produces a frequency response curve that remains flat almost to DC (0 Hz). Most sealed systems designed for car audio use employ a Qtc of 0.8-0.9, to minimize box size requirements and maximize power handling, while still providing acceptable results.

they didn't necessarly say sealed was the best for sound quality. they said it was the best type since the box size is the smallest of the bunch and offsets the 12db octave rolloff. Qtc is overrated anyways. if u want sound quality, u want a bigger sealed box and .8 or .9 qtc will get some pretty peaky frequency response. get a box to yeild a .7 and the box will almost be as big as the recommended ported enclosure.