difference between sub size?

i have seen many post on a bunch of forums about how a small sub like an 8" will hit just as low as a 15" but i have also seen many people tune biger subs lower then they do the smaller subs. wouldnt a smaller sub hit faster because it is smaller? now i can see how with the right box setup a small subs can hit as low as any but for SPL wise wouldnt a small sub be louder at a higher note?

im lost on this can any one make sence out of it all?

 

ok roll off is the term i need to use not "fast" ok

i didnt know what to call it so i used that to get the idea of what i ment out.

so truly there is a diffrence in sub size and how low you want it vs how it sounds. atlest thats what im understanding right? (sorry if i seem dumb im trying to learn)

 

so are you loosing SLP runing 8s at a lower tone? would they truly gain SPL if you ran them higher? and vise versa with your teammates 15?

i have had a few sub boxs for 12s that was supos to be tuned for the subs and also with 15s and the 15s seam to play the lows better to me and the 12s played rock music better then 15s. is this because my custom made boxs between the 2 where tuned that way or is it partly the subs aswell?

i really want to under stand the truth of all this.

 

ok im understanding that any sub will play real low but the lower you go with a smaller sub wont be as loud. like a tweeter will play it but you cant hear it. i mean if i used like a 1" speaker and wanted it to play a 30hz tone it could do it but it would put out more sound at say 100hz



now sound wise theres will be a differnce because of roll off and thats why biger subs SEEM to sound better real low? and like 10s SEEM to sound better at a higher tone like most rock music has.


im really sorry this must be driving you nuts trying to get me to understand this right.

 

ok anether qestion if i made a box tuned to 20hz and a box tuned at 45hz with an 8" sub. would the 8" sub put out more SPL in the 20hz or 45hz sub box?

 

please explan

im talking same power suply same box setup sept tune
would be the only difference.

 

no one has ansered my last qestion

 

thats what i was thinking. basicaly to low and you loose SPL.

personaly i like the sound of a properly tuned vented box.

im really thinking on going back to just 2 15s in my ramcharger and build a new box thats tuned lower. it sounded better when i had just the 2 facing back rather then 4 facing up. mostly because the 4 facing the roof really makes the roof rattle. also theres a window vent right above the subs and when there going hard it makes water leak in but it didnt do it with 2 facing back.

 

mostly i was asking that qestion as a genaral SUV or a test room and just 2 boxs. basicaly swap the sub out of the one box to the other and test the max SPL of what the sub would do in ech box. just to see what box was louder.