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View Full Version : Do you put sub in center of box or offcenter??



bobo244
01-29-2004, 09:58 PM
I have a 15" awt15x and the box im building is 4.0 cubes tuned down real low to 26-27 hz. The dimensions are 19 tall X 19 deep by 36 wide. The the airspace in the box is really on 24 inches wide but the 3" port elbows 3 times and takes up the other 12 inches wide (2.5 cubic feet port displacement....crazy) anyways, i was wondering where i should drill the cutout for my sub? should it pe in the middle of the 24" section of airspace, or should it be offcenter a little opposite the port side? THanks for the input.

iceteebone
01-29-2004, 10:02 PM
wherever you want doesn't really matter. to me airspace is airspace. on my box i had a sealed box for 2 12's. i then bought an idmax 12 so what i did was get a piece of 3/4 mdf the same size as the front but only cut out one speaker whole on the left and covered up the right. i then cut 2 3" holes in the right side for ports so my sub is all the way to the left side and ports to the right and it works fine. you probably didn't want to hear my box story but what the hell

bobo244
01-29-2004, 10:10 PM
i buidling my first box tomroow so i was just wondering that was my only final question was to offcenter it or not. i would like to hear your story but i just heard that it is better to offcenter it. anyone else?

78nova
01-29-2004, 10:10 PM
I thought a 19by19by36 box would be about 7.5 cubes I think im right because don't you multiply width times lenght times height and divide by 1,728 to get your cubic ft.

nweibley
01-29-2004, 11:37 PM
If those are the external dimensions and you are using 3/4" MDF, thats a 6.11436631944 cubic foot box ;)

Basically... (19-1.5)/12 * (19-1.5)/12 * (36-1.5)/12 = 6.11436631944

bobo244
01-30-2004, 06:55 AM
yea but there is 2.5 cubic feet of displacement from the port, the subs displace. is .51 and im using .1 cubic feet of bracing, after all the displacements, it comes out to the net volume being perfect. Anways, do you offcent the sub or put it in the center???

verylowbass1
01-30-2004, 10:33 AM
hey man look put your sub in a 4.0 box tune it to 28 or 30 make the port on the farthest right of the box and sub on the farthest left of the box........make it about 4 or 3 inches off the backwall put 2 braces in the middle........it matters alot where you put your sub at......spl bounces off the back wall then tries to get out right so imagine if you had ur port and your sub right next to eachother........the soundwaves would bounce everywhere besides going out of the box.....my friend at dd tought me this.......email me if you have some questions........[email protected].....

michael