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bass-aholic
03-01-2009, 03:01 PM
I have a box for my 2 18" BTL's and its 9.5 cubic feet and it has 120^2 inches of port tuned to 35 hz. The port is 24" wide by 5" high. Im just not getting the right sound out of the box that i want. It was built for 2 18" FI Q's but i threw these in there. Should i have more port area? Castereo's port calculator said i should have upwards of 250^2 of port area. With my box dimensions i can only manage to raise the port up to 7" high, and make it 21" long and stay at 24" wide. It would put my tuning in the low 30's with 168^2 of port area. What do you guys think. Will i notice a big difference? I am really lacking the low end and thats what i want to fix.

blackbonnie
03-01-2009, 03:04 PM
i think your port area is fine, you right around the 12-14in^2 per 1ft^3. i think your box may not be tuned to 35hz if your lacking low end

bass-aholic
03-01-2009, 03:09 PM
double post ftl

bass-aholic
03-01-2009, 03:13 PM
Port is 24" wide by 5" high by 16" long. I was told it was tuned to 35 hz. I t doesn't sound like it. I don't know how accurate carstereo's port calculator is but it says it only needs to be 6" long to be at 35hz and 16" for 30 hz and if it is tuned properly i want to extend my port a few inches to get my tuning down.

blackbonnie
03-01-2009, 03:16 PM
ive me a sec. ill check for you

blackbonnie
03-01-2009, 03:28 PM
well the tuning i got is 36.86873848hz. so roughly 37hz, have you checked to see if your subs are out of phase? and what is your subsonic filter set at?

bass-aholic
03-01-2009, 03:58 PM
Subsonic is set at 15hz (im careful with what i play) And both subs are in phase. There deafening at the higher notes but they just cant seem to play the lows. If i added 4" to that port what tuning would that bring me to? Also would more port area help lows?

bass-aholic
03-01-2009, 04:22 PM
any helppp?

bass-aholic
03-01-2009, 04:23 PM
I have 120^2 of port tuned to 35 hz would upping it to 200^2 of port tuned to 35 hz produce better low end?

TheyDontWant
03-01-2009, 04:25 PM
I have 120^2 of port tuned to 35 hz would upping it to 200^2 of port tuned to 35 hz produce better low end?

no

SWFL
03-01-2009, 04:31 PM
tune lower like around 32hz

RAM_Designs
03-01-2009, 04:32 PM
I got a little under 37hz tuning as well. That box is pretty small as well, which could be a big reason why the low end sin't where you're wanting it.

IDSkoT
03-01-2009, 04:36 PM
I have 120^2 of port tuned to 35 hz would upping it to 200^2 of port tuned to 35 hz produce better low end?

Think of the port as a passive radiator (Basically a speaker with out a motor). The more area, the more response. But at a certain point, the area is too big and it no longer creates pressure, and ends up acting like the sub isn't in a box at all. Generally, the bigger the port area, the more of a gain you'll get from the box environment. If the lows aren't hitting properly, first make sure that your amp is set to LPF, and I'd turn your SSF up to 25 or so. If you want to get lower notes, tune it lower. I'd tune it to 30, or 32-33. I personally like a low tune. But, it all depends on the driver. I'll be honest, I didn't read the OP. So, I don't know which driver you're running.

bass-aholic
03-01-2009, 04:41 PM
I got a little under 37hz tuning as well. That box is pretty small as well, which could be a big reason why the low end sin't where you;re wanting it.

Yea i think that might be it because after sub and bracing i lost well over a cubic foot.
Hey ryan i might PM you about getting a new box designed for these. Im gonna try to figure out if i can squeeze 12-15 cubes back there.

RAM_Designs
03-01-2009, 04:44 PM
Yea i think that might be it because after sub and bracing i lost well over a cubic foot.
Hey ryan i might PM you about getting a new box designed for these. Im gonna try to figure out if i can squeeze 12-15 cubes back there.

13-14ft^3 before displacement is a good place to start...15 would be great since the port is going to take up ~2-3ft^3.

blackbonnie
03-01-2009, 05:31 PM
yeah i was also gonna mention i thought your box was a little on the small side.

when i was running 2 15" btl's, i had them in a 9.2 cubic foot enclosure and your 2 18's are in 9.5 cubic feet. try and get it a little bigger and tune lower

bass-aholic
03-01-2009, 06:30 PM
I went ahead and extended the port 4 inches and it sounds a lot better now, but still i need to make a bigger box so those subs can really shine.

RAM_Designs
03-01-2009, 07:07 PM
12ft^3 tuned to 33hz would be great.

05_ZX636
03-01-2009, 07:25 PM
i am running 2 bl 18's in little over 15 cubes after subs and port, tuned to 33hz with 200+ square inches of port. It pounds the lows really good, well it sounds good on just about any bass

bass-aholic
03-02-2009, 01:52 AM
time for a wall. and maybe 2 more BTL's :D