Conclusion: I was looking a subwoofer that would be able to handle all types of music. Previously I have used JB Audio, Infinity, Alpine, Kicker, etc.. Finally, this one is what I was looking. The bass is so powerful and punchy to handle all the hiphop/trance/rock music and it was able to handle low frequency very well for classical pop music. One of the best subwoofer I ever used. I wired as 3 ohms and my amp is pioneer 9601 that can handle 750 watts rms at 3 ohms.
Summary: This thing is awesome!! I have it hooked up to a hifonics brx2000.1d amp and I have a 2.25 cubic ft enclosure (needs a 2.75) but dang!! This sub is wired to 3 ohms and is pushing about 1000watts rms. this thing is definitely underrated! This thing also ways a ton and is quality built with gold plated terminals and every thing. It's good for SPL and SQL. It's worth every penny!
Summary: By far the best car subwoofer I have ever heard. This thing produces clean and deep bass that hits you without no annoying distortion. I will own this babe for a nice 10+ years. When your looking to buy a subwoofer, you have to ask yourself how good is the bass. When you look at other lowered price woofers they all have 5 star reviews, so whats the difference between the $100 ones and these ones? If the bass is truly the same then you would buy the lower one.
Excerpt: I changed my systems from Polk which I loved and thought I would try JBL. I believe I have falling in love all over again because I am totally blown away by the clarity of my system which consist of P660c, gto329, p662, p963, 3each w12gti wkii subs, gto1001ez sub amp and gto 840ez 4 channel amp AWESOME!
Excerpt: Having played around with many subs from different brands(many high end)this GTi sub is by far the most musical subwoofer I have ever used.Stunning attack,phenomenal low end without any hints of struggle.Powering this sub using JBL Crown amps puts it on a whole different level.If you are looking for the ultimate sound quality or ground shaking SPL subwoofer,I'd highly recommend the GTi series of subs.
Summary: This sub lives up to every 5 star review. It is a total beast and produces some incredibly detailed bass. I have 2 now - one in a sealed 1 cubic foot box as suggested by JBL for optimal sound accuracy and another in a tank of a ported bassworx box. Both are made of 1" mdf. Thick heavy beastly bass boxes. I have a 2000 watt mb quart amp feeding them and it seems adequate but they could handle more.
Conclusion: wow, what can you say. for starters this sub is rated at 700Watts RMS, but it is quite capable of handling much more! i did contact jbl's tech support and engineering department when i hooked this sub up to my planet audio BB2400.1, i told them that i was sending ~1200 watts to this sub. there response was something along the lines of "oh yeah i know it can handle power." it does get hot but then again this was a subwoofer engineered to take heat.
Summary: I bought 2 JBL W12GTi MkII, 4 years ago, and still bring a powerfull and deep bass, like never before i heard. this subs, need a big responsable amplifier, i had a Power Acoustik 5500 (peak) 1700 rms 4 ohm. but remember this subs had 6 ohm, so for avoid damage it amplifier have 755% gain level. so no extreme for amplifier and no extreme for subs.
Conclusion: I got two gti's when they first came out and got sick of them blowing out. Then i got 2 L7 12" kickers. Not only have they out lived the gti with same power output but they bank way harder way longer, sound better, etc. Buy this speaker at your own risk and if you do purchase a jbl amp. They last longer and are under rated. I did have those for a while and were cheaper and put out for a long time before they gave up on me.