Subwoofer: Audioque 2.5 12" Subwoofer
I bought one of these for my small car (97 200sx) I built a custom 3.2 cubic foot box that takes up just about my whole trunk, the port is about 2.5" wide by 16" high give or take, not sure the hz output it is set up on. Pushing it I have a Audiopipe 1500 watt D class. I have owned 4 of these so far and can't believe how good of a deal these are for sub amps! Anyway, they reccomend breaking the sub in for "months" I have finally reached past more than half power and I have to say... This thing is LOUD I will eventually post pics and possibly videos, everyone is amazed that my back glass hasn't fell out yet, it moves about a full inch outward when the Subwoofer is cranked. Plastic trim on my sunroof is cracking to pieces, my whole dash rattles when the radio isn't turned on, and some screws on my front bumper cover are rattling. I obviously don't have a DB meter to compare this with, but for one 12" sub.. MY GOD. previously I had 2 crossfire BMF 10" in a ported box, very loud but the audioque is louder. And before that 2-PPI PRO flat piston 10" subwoofers, at 30 pounds a piece and 1000 watt rms each, I was impressed with the sound quality, but the BMF's beat them in the SPL category, and more than HALF the rms wattage required. Anyway, back to the Audioque, this thing is very very stiff, and I also wouldn't reccomend playing it at full volume until you warm it up for a long time. You really can hear the difference, it sounded springy when I first got it in, and the bass didn't really roll from frequency to frequency, now it is more blended and smoother. At around 40 to 50 Hrtz is the sweet spot for this in my trunk. I have the port and sub facing toward the trunk of my car so it isn't sealed to pass into my cabin, and it is still that loud. All in all I would give this sub a 3 for sound quality (out of 5 mainly because you have to run it in ported box)
and spl for the value.. a 5 (out of 5 because you can buy one new shipped for less than 150 bucks!)
But be prepared to do some serious box designing, and after spending that much time, money, energy on a box.... you start to wonder... what do the hdc3 and hdc4 sound like? I will let you know soon.