i understand that the box’s need to be certian sizes cause the speakers need the correct volume of air to perform as intended… my question is if the air volume is too small or too large how does it affect the output of the subwoofers?
i recently installed a rear strut bar and need to use a different box than i have now…
thanks…
usually a little over or under doesn’t matter, and to most of us who don’t have super tuned hearing you won’t even be able to tell a difference.
If the box is too big the sub might sound more “boomy” than it is supposed to. And it won’t be as tight and clean of bass.
I’m not really sure about too small of a box. It seems to me that too small of a box could make it not be as loud. Or be able to handle as much power (less air means there is more pressure pushing back on the sub when it moves inward). But i’m not really sure about all of this.
I suggest building your own box. Its pretty easy, and that way you can get it the right volume (approx) and make it fit well in your trunk.
well yeah concidering i can go to home depot and buy a 8’X4’ of mdf for 20.00 . and a shop i gave the diagram of how i need the box gives me a price of 120.00 my guess is ill bust out my skill saw, drill, glue, and screws and do it myself at werk hahaha then take i to them and have them carpet it in black for 10.00 lol…
Too small? Bye, bye subs. You’ll blow the speaker.
You can buy this stuff that looks like cotton. You stuff in into the box if it is smaller than the recommended size and it will act like the sub is in a bigger box. I know crutchfield has it.
use dacron (geeze, all im talking about lately is dacron)
they stuff pillows with it… its real cheap
Too big or too small can really hurt your sub (duh). A simple rule of thumb for enclosures is that you can be up to +/- 25% for a sealed box, +/- 10% for a ported box, and +/- 2 to 3 % for a bandpass box (Meaning simply that you can be either over or under the optimum size for your sub by these amounts without doing real damage to the driver).
The smaller a box is(within reason), the more “punchy” the bass is, so it won’t be as loud, but you might find that you like it a little with a little more kick, but again, go too small and you can hurt it.
If you still have the manufacturers recommended box size, use that, otherwise ask a local dealer what size box you can go down to, or post what kind of driver it is, and I’ll see if I can help.
HTH-
Amrit
Originally posted by Speeddaddy
…then take i to them and have them carpet it in black for 10.00 lol…
Don’t even spend THAT much… just buy a couple yards of the black carpet material, and 3M Spray Adhesive to do a clean job yourself. The 3M spray may seem like too much, but trust me, if you hang around G2IC long enough, there’ll be 101 uses for that can… 
Just don’t glue yourself to uh… yourself…
Too small a box also attenuates your low-end frequency response at a greater rate.
Theile/Small parameters do wonders. Use the manufacturers recommended encloser volumes for the given box design you are going for. If they don’t have the box design you are looking for, take your T/S specs to a shop that can run a box/port program like LEAP or TermPak. My TermPak hasn’t worked for a while, otherwise I’d run them for you.
thanks all… 
download a program called WinISD — If you enter the T/S parameters for your subs, you can model the output however you want, and have a visual graph to look at. Also gives you the exact box size and approximate dimensions to work with (which can be altered as long as the internal volume is the same/similar).
Too big = lower power handling (less air suspension), deeper bass, less punchy, easier to over-excurt your sub (killing it).
Too small = punchier, less deep bass (depending on sub itself, however), BETTER power handling, less chance of overpowering/overexcurting (a good thing), more “peaky” response (not as flat a response, therefore may “coloring” the music a bit more).
Proper box = safe bet.
~Eric