2 18" in an explorer sport

[I want SExxx 10+ year member]

southern california.
ive run only 1 setup with sub and ports back and it was nice. every other setup has been sup up port back.

i thought i read on here that sub up port back is louder on mike and sub back port back is louder to the ear. all i really care about is louder to the ear.

The explorer sport is probably different, but in my explorer subs up port back is loud as hell and peaks louder on the TL, but the same subs, box vol., port area, power ect all firing back peaks a little lower and has a tad bit more pressure. One big thing is if your box is really tall...... anymore then a couple inches above the back seats, then fire up with port back if no firing everythng back.

 

[IgnoreMe 5,000+ posts]

so then i should probably fire up. to fit in a full 12+ cubes net for the subs im gonna need to to probably go like 4" above the head rests.

all i really care about is louder to the ear so any advice you can give ill take //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[I want SExxx 10+ year member]

Fire the subs up and port back, but keep the subs close to the back..... like no more then 4-5" from the edge of the box and make sure you don't skimp out on port area.

 

[IgnoreMe 5,000+ posts]

Fire the subs up and port back, but keep the subs close to the back..... like no more then 4-5" from the edge of the box and make sure you don't skimp out on port area.

why is that? don't mean to keep bugging you with questions but it never hurts to learn more

as far as port area goes, i was gonna do around 180^2 of port. thats going by using 15^2 per cubic foot and using a 12 cube enclosure. is that a good port area for the 18's or do they need more?

 

[IgnoreMe 5,000+ posts]

i want sexxx: heres a good post i found on this website just now

"What year is your grand cherokee?

Take it from someone who has personal experience with them, and not just forum boner riders. My grand cherokee does not like subs up, port back very much.Either subs and ports firing back, or subs foward port back. Then again, I focus more on the meter. No sense in building a new box when it won't help you though.

But honestly, do not build a new box, subs up port back and expecting it to increase output. It's not for all vehicles."

 

[I want SExxx 10+ year member]

why is that? don't mean to keep bugging you with questions but it never hurts to learn more
as far as port area goes, i was gonna do around 180^2 of port. thats going by using 15^2 per cubic foot and using a 12 cube enclosure. is that a good port area for the 18's or do they need more?

Should be enough port area..... just do as much as you can and REMEMBER that the port isn't included in you box volume

Example...... a 40"X24"X28" box has an internal volume of 13.28 cuft. That's not your box volume. you have to take away the displacement of the subs (.23cuft. per BL18) which gives you 12.82 cuft. Now say you wanna tune it to 32 hz with 180sqin.

Here's where you gotta plug and play let's start out and use 11cuft for our calculation. With a 22.5"X8" Port You get a length right at 28" now since you have a depth of 28" I'd try to keep the port length below that by at least the port width....... let's try 22.5"X6.5"......that's 146.25 sqin of port area ...... Our port needs to be 21.75" long .... Well call it 21.5 to make it easy (Its not an exact science.) SO now let's see how much area the port displaces....... 22.5X8(have to include the wood)X20.75(already included the front so -.75) and you get 2.16 cuft now that taken away from 12.82 is 10.66 NET cuft. That will work just fine. Now you have about a 32.5hz tune in 10.66 cuft. So your never going to get it exact unless you really wanna fudge with it..... but it doesn't matter it doesn't need to be.

Just so you know that will get you the perfect box design....... give me the deminsions your working with and I'll help you on that.

Now about the sub distance from the back....... if there at the front of the box(right by the seats) your going to start getting into a tad bit of cancellation and your loosing the benefit of having all he pressure load off the back hatch area.

 

[I want SExxx 10+ year member]

i want sexxx: heres a good post i found on this website just now
"What year is your grand cherokee?

Take it from someone who has personal experience with them, and not just forum boner riders. My grand cherokee does not like subs up, port back very much.Either subs and ports firing back, or subs foward port back. Then again, I focus more on the meter. No sense in building a new box when it won't help you though.

But honestly, do not build a new box, subs up port back and expecting it to increase output. It's not for all vehicles."

He's on crack you don't put subs forward port back. Don't listen to him.

 

[TheFiverMan 10+ year member]

why dont u just try 2 15s to be on the safe side?

 

[I want SExxx 10+ year member]

He's got plenty of room for 2 18's.

 

[IgnoreMe 5,000+ posts]

why dont u just try 2 15s to be on the safe side?

cause ive already had a dual 15" setup //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif time to go bigger!

i want sexxx: i also forgot to ask you how come if im over the headrests by a bit i should fire up instead of back? i understand why you want to fire as close to the hatch as possible, but wouldnt it work out to just fire towards the back anyhow?

and as for the dimensions, ill go get some as soon as i can.

 

[I want SExxx 10+ year member]

cause ive already had a dual 15" setup //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif time to go bigger!
i want sexxx: i also forgot to ask you how come if im over the headrests by a bit i should fire up instead of back? i understand why you want to fire as close to the hatch as possible, but wouldnt it work out to just fire towards the back anyhow?

and as for the dimensions, ill go get some as soon as i can.

If the box is really tall...... like a foot from the roof..... then the pressure behind the box is going to build up a lot more then if it were shorter and your going to loose output from the back hatch flexing too much AND your blocking off a lot of the path that the soundwaves will use to reach your ear. Not too mention that you run serious risk of breaking somthing back there. I broke my wiper motor and it only likes to work about half the time. You do however still want something firing back and that's where the port comes in.

 

[audioholic 5,000+ posts]

This isn't an Explorer but here's a pic of my Bl 18s. 13.5ft 192.5" of port tuned to 32hz.

Wow that box is really small for 18's... Im surprised it does well at the lows.

 

[IgnoreMe 5,000+ posts]

Wow that box is really small for 18's... Im surprised it does well at the lows.

im assuming its 13.5 after displacement. why is that small? fi reccomends 6-10 cubes per.

 

[IgnoreMe 5,000+ posts]

If the box is really tall...... like a foot from the roof..... then the pressure behind the box is going to build up a lot more then if it were shorter and your going to loose output from the back hatch flexing too much AND your blocking off a lot of the path that the soundwaves will use to reach your ear. Not too mention that you run serious risk of breaking somthing back there. I broke my wiper motor and it only likes to work about half the time. You do however still want something firing back and that's where the port comes in.

not really worried about breaking the wiper motor...its already broke lol. but i do understand what your talking about.

ill try to get some measurements in a few mins.

 

[Goldtaz1 10+ year member]

Wow that box is really small for 18's... Im surprised it does well at the lows.

Sorry dude, but that is more than enough box for 2 18's. If he had more power they would really love a smaller box.