so i've been looking at speakers and, as we all know, the 4 main parts of a sound system are 1. head unit, 2. speakers, 3. sub(s), 4. amplifier.
But I'm looking at the alpine x series speakers, http://www.alpine-usa.com/US-en/products/product.php?model=SPX-13PRO〈=en&tab=D
and in the picture it...