2 8’s vs. 1 15?

hey guys me and my friend known as Ajrxtreme on this forum got into a debate about which subs will be louder. He says that since 2 8's have 16 inches of surface area that it will be pushing more air as appose to 1 15in sub. This seems hard to believe but i had a hard time explaining it to him. If you guys could please inform Ajr oh how he is incorrect and why, thanks.

Tell AjrXtreme he needs to pay more attention in school.

Area of a Circle = pi * r^2

So, an 8" driver has an area of AT MOST:

3.14 * r^2 = ~50 in^2.
2 8" woofers have AT MOST ~100 in^2.

Now let's look at the 15":

3.14 * 7.5^2 = ~176 in^2.

The actual measurements will be smaller than this because the usable cone radius is actually much smaller - but they'll be relative and my conclusion will still be true: Ajrxtreme is wrong.

For low bass usually the bigger the better - enclosure size being your only limiting factor. Larger drivers are generally more efficient and can play much deeper. It would be a sore mistake to think 2 8" drivers could always beat a similarly built 15".

Please note that there are exceptions: if I only have 50 available watts and I'm trying to determine what will be louder for me, at say 50-100hz, then a set of efficient 8" drivers will be louder than an RE XXX 15"

However, IN GENERAL, a 15" driver will be more efficient than an 8" and more capably reproduce low frequencies.

The moral of the story is this:
1) Ajrextreme is wrong about the surface area
2) In general a 15" will be louder over the bass region than 8" drivers.
3) #2 is a generalization - there is much more to the analysis. Every person must evaluate which subwoofer will be right for his or her application. Flat statements without qualifiers can almost always be proven wrong. Avoid them. Always conduct a complete analysis when designing your system.

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New Project: 2003 Pathfinder

alrite thanks man.