Here are my $.02 regarding the Digital Designs e-series 12" subwoofer.
First off, the box makes a huge difference in almost any subwoofer application. So first note two things:
A: My box is 3.33 cu-ft ported/tuned to 28hz - 1" MDF Custom Built by LoneRanger (actually for a XXX).
B: Your results may be slightly/moderately/severely higher OR lower depending on your box design/construction.
ALSO, this was in the trunk of a 2000 Dodge Stratus, facing the rear with NO sound deadening as of yet, and the back seat was folded down for maximum SPL.
I do not have any metered numbers, I will try to get them asap.
OK, for the review. Subwoofer specs can be found at: www.ddaudio.com
But the basics: 1200 watts RMS, 2500 watts (they say "music") peak
Sub is 12", 47 lbs with 29mm of excursion (while retaining 8mm in the coil)
I was running a Hifonics Brutus BX1500D amplifier to this sub. The subwoofer is the 2 ohm Dual Voice Coil model. It retails for $609.
First off. It is a very clean hitting sub. My first time listening to a subwoofer of this caliber, but I was very impressed. I was able to run this sub plenty loud for daily driving with my gains all the way down, and it hit very clean. By turning the gain approx. 1/8th the way up, I noticed a huge jump in SPL. I turned the gains to about 3/8th the way up and that was the highest gain setting that I used; I noticed another slight jump in SPL. For my listening purposes, I decided that 1/8th was plenty, as the subwoofer sounded very clean.
My trunk rattles a lot as I have no sound deadening. As I have no numbers to tell you how loud it is, I will just go from a few experiences:
A: My brother was in the car, we had the windows down, and we could barely hear each other talk. He said, "WOW, I can feel my hair moving around."
B: I was showing the system to one of my friends and he was very impressed. Windows were up. I was playing D4mn by Little Jon. At this point his girlfriend came out of the house and said, "You are shaking everything in the house."
That's really all I have to go by, and I've only played the sub for a few hours, and it's starting to get broken in really nice. I was a little worried about this sub at first (because I had it in a crappy sealed box), but once I got it in the good box, it hit very clean and very hard. I would guess that you could gain some more SPL by having the box ported higher (say 45hz), but my guess would be that the lows would suffer.
It does a decent job of hitting the lows (~28-30hz), but I wasn't all that impressed. Once it got to ~40hz, the SPL is amazing.
I hope to trade this for a XXX so I can do a review on that sub, and compare them. Thanks for taking the time to read this, please let me know if this helped, or if there are errors so that I can edit the post as necessary. Also let me know if there is any important info that I left out, so that I can update it before the mods close it. Thanks.