DB124 Sub in a slot port box - box help?

Systems

I've bought a polk audio DB124 sub and built a sealed box thats 1.3cu ft. The reason I built it so big is because i want to port it. I want to get a little more bass out of it, and im sure porting would be the answer for that. I would like to make a slot port but if I have to I would make a circle port. The box is (ID) 18x18x8. It fits in the spare tire well of my mustang. I have the sub offcenter so i could have room for the port. With this box im using an audiobahn A2002T amp bridged. So far it hits pretty good but I want some more power out of it. Help me out plz

I would like to know what size port to make exactly. I've tried numerous programs and cant figure them out. I listen to rap/rock and bass tests so i would like ot have something that impresses people. Also what kind of port should i use for my application and why? Thanks

neomagus00

i like slot ports, cause they're more out of the way and infinitely easier to fold, so we'll run with those.

if your box dimensions are 18x18x8, then your gross internal volume is 1.5 cubic feet, not 1.3 as stated. i'll run with that 18x18x8 box.

i have to assume that you want a low tuning, so it still sounds like music. for the physical box to work, i have to assume two things. first, that the sub has at least 3 inches of clearance all around the edges inside the box. this should be no biggie. the second assumption is that a port coming out of the side of the box will not be blocked (that means that it needs at least 3" of clearance around one corner of the box, doesn't matter which). the reason for this is that you don't want a port that's too long and narrow, and trying to fire the port in the same direction as the sub would do exactly that; don't worry about the sound, it doesn't matter which face the port's on.

balancing all this gives me a box that has a final tune of about 27 Hz, and gains 1-1.5 db over the entire sub-bass spectrum over the sealed box you're in now. as a bonus, i tried to make it easy to install in your current box - three rectangular pieces of 3/4" MDF, a drill, and a caulk gun, and you're done.

so, you'll need to make sure you cut off some time before 100 Hz, cause you'll resonate at 168 Hz with this design, and you will absolutely need a subsonic filter at 25-29 Hz

Systems

Well I went onto the polk box information and it said they had a box that was 1.5cu/ft with a 4" circle port that was 10" or 11" long (forget) I cut a hole and put an angled piece of PVC pipe as a port. All in all its about 8" long with a 4" opening. The thing doesnt hit as hard as the sealed box and it sound crappy. The lower notes (like in rap or subwoofer bass test stuff) just makes noise but doesnt really "BOOM" and hurt your ears like I want. I'm disappointed to say the least. I dont want to make a whole other box, but I did make this box to be able to build a replacement top easily for this reason. What would you recommend in this situation? The boxes inside dimensions are 18x18x8. The sub fires up and sits in the spare tire well. Every piece is glued and should be air tight except for the top piece. In another car I had I had a MA Audio 800w amp going to an audiobahn 15" DVC sub (just a cheap one) in a big slot port box. Those generic ones you get at car stereo places. That thing pounded SOOOOOO hard. Everyone heard me comin and was always impressed with it. Obviously you'd need to hear it to understand how it sounded to bass your help on but I would like something thats BOOMY and really pounds out the bass. Somethin that I would need to turn the bass down on my pioneer dehp7700 head unit. (also could you help me figure out whats best as far as settings for that?) I dont know what alot of that "Q - 2N,1N,1W,2W" crap means etc. I wish i had the experience you guys do! Thanks alot for all the help! If its easier, send me an instant message on AOL IM - BoostedStang281

Thanks again
Andy

Systems

I am using an audiobahn 4004t 4 channel with the crossovers to the door speakers set at HPF and no bass boost or subsonic filter. Not sure exactly what frequency they're set at.

For the sub im using the audiobahn 2002T 2 channel with the crossover set at LPF and the HZ is around 80 with bass boost on the gain about 3/4 up. Subsonic filter is on, and around 40hz i would say.

Any ideas what i should do? I didnt line to box with that stuff? (what is it btw). I have some poly fill stuff i could put in there, should i? I haven't messed with inverting the sub, which can be done easy on the cd player i have but it didnt seem to do much when i did it when the box was sealed. =/

Also will alternator noise greatly decrease the total sound quality of the stereo or just annoy the occupants at low volumes? (meaning is this some of my subwoofer sound problems...)

Thanks alot for all the help im learnin alot