Port Advice, Just Got Metered Need Help

[jimbo92259]

alright i just metered my grand cherokee the other day and i hit a 147 in the kick 34hz peak on tl outlaw ....first time ,,kinda sux, i really wanted 150.... i think my box is tuned a little low ....i am running 4 mtx 9500 12's in a 10cu ft after displacement box . the box has 2 slot ports 3.5 x 10 x12inch can someone tell me what its tuned at and how short should i make my ports to achieve higher spl.... im also getting some major flex issues which has got to be hurting my score

Edited December 10, 2008 by jimbo92259

[kingsuv]

34hz is super low to try to burp with but nice for music.. For SPL you will want to raise up the tuning to get a better score. You can do this by making the ports shorter. I would cut off an inch and test, another inch and test and so on until the numbers quite going up.

The best thing to do would build a box that is closer to the res freq of the truck. I would guess it's in the mid 40's in hz.

If the flex issues are with the box then u need some bracing. if it's with the truck, there is a few things you can do like foam, sound deadner etc. It may or may help your score. Stuff like that can also change the res freq of the truck also, so keep that in mind.

[tibs]

alright i just metered my grand cherokee the other day and i hit a 147 in the kick 34hz peak on tl outlaw ....first time ,,kinda sux, i really wanted 150.... i think my box is tuned a little low ....i am running 4 mtx 9500 12's in a 10cu ft after displacement box . the box has 2 slot ports 3.5 x 10 x12inch can someone tell me what its tuned at and how short should i make my ports to achieve higher spl.... im also getting some major flex issues which has got to be hurting my score

if it is 10 cu ft

3.5 x 10 x 12 long

about 33 hz if i did it correct

[jimbo92259]

flex issues are with the car there are vids of the flex in my cardomain on my sig ..... making the ports shorter sounds good but a meter is hard to come by

[jimbo92259]

thanks tibs .....do you know how short it would have to be for lets say 40hz

[kingsuv]

The flex will change some with the tuning. It won't be as dramatic I would shoot for 42-45hz. it's higher to help increase your score without losing too much low end for music.

If a meter is hard to come by then it's a matter of changing before each show2 and keeping track of what u do and how much it changes. I made 26 boxes one year competing. the only meter time I got was at a show.

Breaking a 50 is hard work, but worth it.

[meade916]

,,kinda sux, i really wanted 150....

i dont know how many times ive heard that Dont put the meter on the dash or you will REALLY be dissapointed

147 doesnt suck though man (even in the kick) - its actually pounding pretty hard at that point.

[00sdime00]

Those are respectable #'s at that low of a freq. I agree with Kingsuv....bring the tuning up and open up the port a bit if you're after #'s.

[Nightshade]

For 40hz you'll need to make each port 7". If you want to go higher just cut off a half inch until you stop gaining on the TL. Then you will have the highest peak that your car wants to play.

[Boon]

If you want bigger numbers you need more port area, IMO. Maybe twice as much area with 18" long ports should give you tuning a shade under 40hz and should give you much higher numbers. Expect to lose a lot of musical ability though.