I know you are not suppose to take efficiency into consideration but what if you were comparing 2 different subs from the same company?

I had been thinkin about goin with 4 Lvl4 15s and they have an efficiency rating of 89.4

The Lvl4 XL 18s have an efficiency rating of 94.77?!?!

So... 4 15s efficiency should be 95.4 and 2 of the 18s should be 97.77...

am i to assume that the 2 18" XLs are gonna kill the 4 15s?

I know 4 15s may have more surface area but efficiency plays a role in that and apparently, it doesnt apply here.

Lookin for some crazy numbers in the lanes and just wonderin if i'm bout to buy the wrong thing...

I have one lvl4 xl 18 and it is doing a 150.2 at 47hz,i had 2 Audioque sd 2.5 15's and did a 150.2 at 53hz so i would say yes the 18 can be louder if not the same!

great, now i'm really gonna be stuck as to which to buy...

2 XL will save me both money and weight.

How much power did u have goin to your XL?

I'm gonna have a 3,500w amp to push either a single 18 or a pair of 15s.

Comp box volume = 15.5 cubes NET

Music box volume = 12.8 cubes NET

Im running a Sundown 1500 at 1/2 ohm

i should have asked this earlier, walled or no?

I just asked this over at CA and they really have no idea either, lol

That is a good number though!

Its a 7cf box tuned at 32hz sub up port back!In a 2008 hyundai accent hatchback.

if you are using two 3500w amps id get the lvl518 same soft parts as the lvl4xl but more magnet and i think slightly better cooling. the extra motor force should help edge out the 15's

Jesus...

Well, i was talkin with someone else a while ago and they told me that they seriously believe in bass race, the 15s should walk over the 18s due to power compression but for a burp, it's a toss up.

So.. unless i'm persuaded, the 15s still seem reasonable.

if you are using two 3500w amps id get the lvl518 same soft parts as the lvl4xl but more magnet and i think slightly better cooling. the extra motor force should help edge out the 15's

Cant, weigh too much, i want to stay below 140lbs on woofers.

relax take a deep breath and just pic one neither is a bad choice and if there is a diffrence in output it wont be much with either setup i could see low to mid 50's with a good box. id worry more about getting the box perfect.

that's basically what i want to make sure of, hehe, that i didnt drastically make a wrong choice at the last minute.

I've always been eyeing the 15s anyway.

This is what i'm hopin to pull -

My last setup was 2 12s and 2,300w of actual power, i pulled a 148.0 in clinic and a 147.7 actual, 129.4 Driveby!

That was in a hatch firing forward and not sealed in the back either. Little trickery with the box design though.

With this wall, i'm hopin to pull around a 152 burp on no more than 120A worth of fusing. For full out burping, no fuse limitation, hopin for a 155.

I'm also expectin to do 150+ on music.

If i can meet those needs, i'll be happy.

I am running 4 lvl4's with two jbl crowns 2200.1 so about 4400 rms roughly at 14.4 volts

Doing 155 burp

And music peak at 154.5 and bassrace at 153.5

16cubics tuned to 35.