stupid question

[truckaudioman 0]

Ok, i will probably be running 2 bls off of a sundown 3k. Not sure if i wanna do 2 15's and keep them straight upright firing through my blowthrough or have 2 18's slightly angled firing through it. What i am curious about, is there really an audible difference between the size of these two woofers if they are running the same power. I know the 18's will probably score higher in comps, but i doubt i will ever compete, so no point in getting less than a db more and losing that much more of the bed of my truck.

[KU40 173]

there is a theoretical 1.5 db increase due to cone area increase and maybe 1 or 2 more due to efficiency increase in the 18s. So maybe about 3 db.

[coobies5 43]

more cone area, thats about it, so of course it will be louder the bigger you go. but thats all up to you.

[truckaudioman 0]

ok, i was told so wrong about db increases then. i was told for a 3 db increase from cone area alone you would have to double the amount of cone area....but then again, he also told me RE subs were the best subs made, even the new ones.

[rushnrun 14]

With a 44% increase in surface area and the same amount of power your probably going to see a gain.. anywhere between 1-3 db.. however it all depends..

I don't believe there's any easy science to it... even though it's the same woofer... the two different sizes have different parameters (efficiency ect)..... different box requirements....

I'm sure the 18's would be louder but I'm not sure how worthwhile it would be..

I think the old rule they use to push was 2x surface area and 2x power = 3db louder... (by "they" I mean the old audio shop (1998) in my town...)

generally I don't worry about any of that though

I like bunches of power and itty bitty woofers..

[KU40 173]

ok, i was told so wrong about db increases then. i was told for a 3 db increase from cone area alone you would have to double the amount of cone area....but then again, he also told me RE subs were the best subs made, even the new ones.

that's true. double the cone area is a 3 db increase. But since you're roughly halving the double, as rushrun calculated (44% increase), you may get 1.5 db increase.

but that's if you keep the same power. If you double cone area and double power it should be 6 db (in rushrun's example).

[truckaudioman 0]

gotcha, and i am pretty sure 1.5db isn't a huge audible difference, so i might as well save the room and go with the 15" subs.