Some box for trucks are shaped like " |\ ", where the other ones are square (rectangle). Does the shape of the box impact the sound the sub deliver?

I have a 1.5 cubic feet square. But it's taking up a lot of space. I was thinking of getting a "truck style" one. I also read that 1 cubic feet is what I should hav for a 12."

Will it:

1. Effect the sound negatively
2. No effect on the sound (but you'll get some extra space back)
3. Don't waste your money

Thanks

 

GoLowDrew,

Nah the shape of the box should not matter how the sub sounds. It will only change the way the sub fires the sound. But most people do not care which way the sub fires. And angled up or down a couple degrees is not going to change anything at all. I bought a prefabricated box when I ordered my sub. The sub needed a box with 2 cu ft so I just bought a standard box. It was just about square. Well that worked well in my old car. But when I got my Civic I had major issues getting the box into the trunk (it didn't want to go ) with some grease and a damn shoehorn it went in . But is was very deep and took up a lot of room. After about a year I paid a guy I knew a little money and he made me a custom box. The box fits perfectly into my car. It is angled to fit flush again my back seat it is longer instead of being deep so I have a trunk again and we were still able to keep the cubic feet to spec. I would say pay about $75-$150 for a nice custom box. Could be cheaper, just look around.

Good luck

-Matt W
White 99 EX





[Modified by 99VTECex, 2:42 AM 7/14/2001]

 

so what book did you get that info from Teken? Next time at least put it into your own words instead of doing it verbatum. Anyways, to answer the question that you failed to answer, no, the shape of the box does not matter. The thing that matters alot is the size and the kind of box. dont put a sub that requires 1.5 cu ft of space into a box that is only .75 cu ft. it will sound like your grandma is in the trunk farting. and if the sub is meant to be in a ported box, dont put it in a sealed one, if you follow these guidelines you should be fine.

 

now now boys no fighting
not sure but every speaker requires a certain air space, cubic feet or whatever standard metric BS.


[Modified by frqntflyr, 6:24 PM 7/16/2001]

 

Simply put, every speaker has a set Thiele small Parameters. They are basically the electrical and mechanical characteristics of the speakers. The type and size of enclosure is generally dictated by the stiffness of the speakers suspension and how low you want to play. If a speaker has a recommended volume of 0.75 cu.ft sealed, you can easily put it in a larger enclosure or a smaller enclosure. The only thing that will really change is frequency at which it begins to roll off (begins to loose it's response) and subjectively how it sounds. If you put a sub into a smaller enclosure than recommended, it will sound more snappy.

 

Here's an excerpt from JL Audio's tutorial section on their website....

Enclosure Shape
While it is always a pretty good idea to stay away from perfect cubes, they don't necessarily have to be avoided like The Plague. Due to the very small dimensions of most mobile subwoofer enclosures, there is little chance of generating standing waves in the enclosure (standing waves cause nasty response fluctuations). For a standing wave to exist, the distance between parallel boundaries must be 1/2 the wavelength of the frequency at which the standing wave exists. Considering that sub-bass waves vary from 56.4 feet (20 Hz) to 11.28 feet (100 Hz), the generation of a standing wave is going to be impossible....after all, the enclosures we're speaking of have to fit in the average sedan or hatchback!
Any standing waves that might be generated by upper ordered harmonics (caused by distortion) in the enclosure can be readily absorbed with the addition of damping material such as polyfill (available at your local cloth store--it is used to stuff pillows and quilts) or Fiberglastm (the pink stuff) and/or they can be broken up with strategically placed bracing within the enclosure.

In short, don't worry too much about shape. Make the box to fit the space you can allot to the enclosure and forget about it--there are more important things to worry about...like bracing.

For more info just check out their site. You'll find a lot of useful stuff.

 

For a sealed enclosure you can make any shape you want, however one to avoid is a perfect cube because standing waves can result, but even then it's not that big of a deal. Just make sure that you use a extremely stiff non resonant material (MDF is the standard choice here) usually 3/4" thick although I like 1" but that's me.

Next use a ton of screws to hold the box together and caulk all of the edges w/ excessive amount of caulk. For a 1.5 cu ft box, I go through one pound of drywall screws and one and half tubes of caulk to give you an idea. You just need to make the box air tight and stiff.

But yeah, that JL site is really good to learn off of.

 

I would like to say! I found that shape of the box matter's little! Instead of concentrating on an exotic shape, you should concentrate on materials. Lately I have been using 3/4 inch high quality birch ply wood and also oak! I believe I get the best sound from these materials because they are higher density and stronger than mdf! There is a very noticeable diffrence. The birch box with same air space seems to produce a tighter sound. Also these materials hold up very well and run 20-30 dollars a sheet! Then I seal the boxes with great stuff for a supper airtight seal.

 

In most cases, the shape may not matter, but I have experienced times when certain enclosures performed better in certain vehicles, than the same enclosure in another.
I previously owned a 1990 Mazda B2200 standard cab pick up. I had a custom enclosure built and installed in the truck. It was built to fit behind the seat, in an upright position with the sub firing into the seat back, and the port corner loaded. Well, I sold that truck, and after about 8 months, I found a 1986 extended cab Mazda B2000 to buy( this is the same body style, they ran from 1986-1993 ). I installed the same subwoofer enclosure in this truck, however this time the subwoofer fired up toward the ceiling, and the port was firing into the oposite corner, I had layed the box on its back and turned it arond to fit the extended cab.
The system lost a lot of bass response and clarity. I know I was now trying to pressurize more internal airspace( larger cabin area ), but I have heard several similarly powered single sub systems in extended cab trucks that sounded way better. I talked to the shop that built it, and the owner said that a different shape enclosure should fix most of the problem, we double checked the specs, and the box was/is correct for the Cerwin vega 10" sub installed into it.

I have also had friends experience similar things with prefab truck enclosures in hatch back cars! It may not happen every time, but see if you can find somebody to let you test their truck enclosure in your car first.