Well I was looking at the specs on the MusicMoose box that I ordered (I came in the mail today and it's beautiful ) Anyways it says that the box volume is .73 cubic feet per chamber, so then I take a look at the subs I'm going to be putting in the box (Rockford stage 3 12's) and they're .75 cubic feet... so what is all of this mean? I know it has to do with air space and pressure (Or atleast that's what I'm assuming) can anyone clear this up? And will it sound good even though they're .02 off?

 

Well, that .75 cu.ft is probably minimun reccomened airspace for that sub.

Once you put the sub in there airspace will go down even more, so you will end up with maybe .65ish cu. ft in the end. It should work alright. Might be lacking in bass some, but it will work

 

A simple answer to that Q is no. The specs given by the manuf. are reccommended for optimum performance. Any variance +/- will still give you a really good sounding bass note.

Everyone feel free to correct me if I'm wrong, but I'm speakin' from my own experience here. Using the same sub in various size boxes has taught me this: The bigger box makes the lower notes sound better. It takes more power to run the sub. A bigger box softens the thump sound from the woofer, creating a smoother sounding, more enjoyable bass note. A smaller box will need less power to run, will produce punchier bass, and will not hit the lows as nicely. However, until you listen to 2 drastically different sized boxes in your truck, you are not gonna realize a difference. By drastically different size I mean a .75 box versus a 2.0 box.

 

You can always trick your subs into thinking they're in a bigger box while tuning the box at the same time.

http://www.crutchfield.com/S-POvN45w...eview&i=027808

 

Yes... decieve the subs... BRILLIANT! But it says to use 1 to 1 1/2 pounds per cubic foot of box space... so... in theory, if my box volume is .73 cubic feet per chamber then a pound and a half divided evenly between the chambers would be kosher?

 

yeah, that would work.... my sub box is 1.20 c.f. and I bought 2 lbs. Going to play around with it and put 1lb in first then 1 1/2lbs and see if there's a difference.

 

I believe you got the power requirements backwards. Smaller than optimum box yields higher power handling by the sub but higher required power to attain the same volume. Everything else you said perfectly regarding sound quality. But the numbers you referenced were for a standard sub. I built a custom box for my 2004 F-150 Regular Cab with 4 chambers at .62 ft3 for each chamber without a specific subwoofer brand or size in mind. I then search for a sub that required exactly that much space for it's optimum sealed enclosure. I stuffed each chamber with a pound of poly-fill. My 4 tens each get 150 watts RMS and plays loud and deep without the usual punchiness of a small enclosure.

 

I see. Good point. You say that you "stuffed" each chamber with poly-fill. If you take away all that airspace, doesn't that affect the throw of the woofer and the sound? I know it softens the note, but do you feel it's good to "stuff" an enclosure? What about "air" space? I've always only put enough poly-fill to fill about 1/3 of the chamber. Now you got me wondering if I should stuff it full...I'm building my sub box tomorrow, so I guess I'll have to test my theory and do it both ways to see if I notice a difference.

 

Keep me posted DarkStone!

100th Post! Cheers to all!

 

Now that you mention it... i didn't really stuff it. You're supposed to use 1 lb. (16 oz.) of poly-fill per 1 ft3 of air space for sealed enclosures. Now that I am remembering more of my box construction... I ended up using about 12 oz. of poly-fill per .62 ft3 of volume. This ended up filling up about 80-90% of the internal volume. My box sounds great and is tuned for 56 hz with an F3 of 44 hz.

 

Are you serious or is that a typo??

 

Bartak... Not a typo. I tuned the box for rock, not rap. I've had 18" subs all the way down to 6.5's. I tend to like boxes tuned at 50hz due to the type of music I listen to.

 

Hmm, thats cool. I guess I was going to add you must mainly listen to music that doesnt get real low. That box must be loud for rock though

I like low tuned boxes personally (like 30ish Hz) to keep some SQ.

 

how are you dialing those in? At an audio shop? or is there some at-home device?

 

Darkstone, do you mean the boxes and tuning?

Box size, port area, and port lenght all factor into it. You hafta know your box volume, and port area (diameter of port if its round, or 'face' area if its square/rectangle) and what you want it tuned to, then there is a mathmatical formula that you put it all in and if will tell you how long you need your port to be to tune it to that particualy frequency.