Port Lenght

CarolinaCartel · Post by **CarolinaCartel** » July 7th, 2007, 3:22 pm

I'm building a box for a Kicker L7 15. The box is 4.33 cu ft before speaker and port displacement. The port opening is 3 in W and 17.5 in H. How Long would it need to be to tune the box to 36 hz. Right now the port is 16.5 in long. thanks for any help you can give.

chew* · Post by chew* » July 7th, 2007, 3:51 pm

You would have to run it through a box building program to tune it, or you can tune it by a meter with a sine wave. Technically if you want it tuned for 36hz as your peak you would actually have to down tune it to account for the rise time of the sub so say 30-33 hz to peak at 36hz.

You can get a meter and run the max length port usable in your box. I would cut 2 exact lenghts. Using the 36hz sine wave at half volume and slowly trim the port down till you peak out on the meter writing everything down, basically the meter will yield higher spl as you trim and once it starts to decline that would be your peak, I would add 1 inch to the peak length result as at full volume your frequency will change by about 2 hz.

Curiosity makes me wonder why 36hz? If your trying to tune for the frequency of the car or spl your about 20hz off. For sound quality i would tune to 25-30.

CarolinaCartel · Post by **CarolinaCartel** » July 10th, 2007, 4:21 pm

I was told that 36hz would give the best overall sound for my car. I don't complete i just want something that would be cross between spl/sq.

PS i builded the box and i'm pretty happy with it. I took to a local shop and it did 136 with 1 15" kicker L7 with only a 400 watt memphis amp. i think the box will be ok for me but i'm looking to upgrade my amp asap. i plan to get a kicker zx1200 or a autotek 1500.1d. but got to see how my money goes.

chew* · Post by chew* » July 10th, 2007, 8:22 pm

There is no such amp as the kicker zx1200, autotek can't make a good amp to save they're life now. Kickers new line blows chunks also imho. Go get a used kx1200.1 kicker and you will have a decent amp.

lakersfan1 · Post by **lakersfan1** » July 10th, 2007, 8:41 pm

A 36 Hz tuning frequency for a 15 is the SQ tuning? That'd have as much SQ as shoving a cat turd in your ear. I don't even tune my 10's that high. I don't have the Thiele-Smalls for the L7 in my box program, but I'd venture to guess you'd want it under 25Hz. My 15" is tuned to 18Hz to hit the LOWWWW notes on some of my stuff that has bass cello or organ.

chew* · Post by chew* » July 11th, 2007, 4:21 am

Agreed lakers but IRC the squares don't like LOW LOW frequencies, They lose control tuned lower than 25hz, then again i would never use a square or a 15" sub for SQ anyway. The cvx however is very comparable to a JL in SQ reproduction. I prefer the 12"s however the JL 10"s are a tough sub to beat in the SQ department

CarolinaCartel · Post by **CarolinaCartel** » July 11th, 2007, 12:41 pm

thanks for the input guys. Laker if i can get you the spec for the L7 15 can you check the tunning for my box?

lakersfan1 · Post by **lakersfan1** » July 15th, 2007, 1:24 am

CarolinaCartel wrote:thanks for the input guys. Laker if i can get you the spec for the L7 15 can you check the tunning for my box?

Yep.