Can someone please explain SPL to me?
 

I was under the impression that the maximum SPL that a system could reach was based upon sensitivity of the drivers, but after looking at the specs of some of the high dollar brands, there's obviously some other factor in play.

For example, there was a video of a competition on youtube where a guy was running a single Level 5 @ 2k or something and was hitting somewhere in the 140's

Now, I was going off of sensitivity, and the level 5's only have like 87db @ 1w/1m, so there's no way that this is the correct factor that i'm looking at

So, my question is, what makes a system like this so loud?

Does the amp have insane bass boost?

Is it Cabin Gain?

Is the box that good?

Any help would be appreciated, thanks in advance

the box makes a difference but that is just the start

sexual pressure level

box, power, cabin, port and tuning.. a million different things

I guess I didn't realize how much the box mattered to SPL

The final Question I have is about 2 different subwoofers

The level 5's have an efficiency of like 87db

I was going to build a cheap system with the Boss Phantom 15"s, which have an efficiency of 96, and a power handling of 1250 W

Now, I guess what i'm wondering is if the phantoms could, in theory, beat the level 5's, just because of that difference in efficiency?

I'm under the impression that every doubling of the wattage should increase DB output by 3, so even running at 1000W, shouldn't the level 5's have to run at almost 8000W just to match them?

Am I doing something wrong?

forgive my ignorance, as you can tell, i'm a newbie at this sort of thing...

This is actually quite an interesting question. I don't know how you could effectively compare 2 drivers using only stats.
On top of the power/box/placement/tuning etc there are factors such as build quality, and how each driver actually sounds; some may appeal to you (and may not be the most efficient) while others, you may just not 'like' the way they reproduce sound. Don't forget that personal preference factor; it's YOUR setup.

I know nothing about SPL builds or competitions... Audio1der, I think the question he's asking isn't relative to the quality of the bass being produced, but rather the volume of bass that'll be measured on the "TermLab" or what ever that contraption is called.
If we took the Level 5 sub, and the Boss Phantom sub, and ran them through the "bass test" with no other variables in setup, he's suggesting that the Boss sub would perform better simply because of it's higher efficiency rating. 96 vs 87. Theoretically, he's right. But there doesn't appear to be any specific standard to which car audio is held. And number can be "created" by testing the equipment in a different way.
Regardless, if those values were 100% accurate, then yes, the Boss sub would be louder than the Level 5.

if thats a dc level 5 then the phantom doesn't have a chance

larger voice coil and motor will push larger volumes of air

my two cents :)

See, that's the thing I don't understand about the magnet size and everything else

if it's so much better, than why would the sensitivity not be higher?

Should I only be looking at magnet size when deciding on a subwoofer?

This all seems very confusing to me...

I have been throwing sound offs for 5 years now, and this is a great question...Why does my fist system with 9 SVC cheap subs, and 1200watts, out perform a high performance subs and expensive amps...Well......testing testing testing testing. Box design, box design, box design.....Oh the boxes I've thrown away (or sold to some guy cheap).... I love it when guys spend under a $1000.00 bucks on their system (from me of course), and are louder than the guy who spent twice as much, or purchased from some on line company because of the on line opinions and specs...
There is a very simple explaination for this dilemma. efficientcy at 1 watt 1 meter is much different than 100watts at 1 meter or 1000watt at 1 meter....a cheaper sub with a high sensitivity of 90db at 1 watt 1 meter is usually not as stiff as a sub with lower sensitivity...as the volume goes up, and the sub starts to move more air, there will be a point at which the stiffer sub will be creating more SPL because it is not as sloppy and more controlled (traditionally), therefore moving more air at higher volumes... With all that being said, you never know what you are going to get. I saw a guy do a 140 with 2 visonic 10" subs and 300watts last year, and took a first place in Street Stock A.

Alright, thanks for the input

I guess after hearing that info, would the Boss Audio Phantom 15"s actually be reasonably loud?

The construction looks really good, so I assume they should sound pretty decent?