I have no stock or reward from JL Audio at all. I am just a small studio owner scratching my way like most of us. I was just blown away and had to share this excellent bang for buck sub from JL Audio.

I have a recording studio called Alcorn Studios. The studio has a listening room 16x24 feet. The listening room is partially anechoic. Anechoic insulation of 8" intermittently (mostly) on all the walls, except 1.5 feet of anechoic insulation completely covering the wall behind the listener. Corners and areas behind the speakers have special anechoic treatment. Extremely large bass traps exist. In summary, a very good listening environment and I am a good listener.
My full "ERA Design 14"speakers are good, but have a slight bloom at about 50Hz, and need some extra help at about 20-30Hz range. My old Monitor Audio FB212 subwoofer just died, again, and I needed a new subwoofer low passed at about 30-40Hz.
I went to a local relatively high end audio store called "The Little Guys", to look for a high end subwoofer. I explained the application and the sales representative (Henry) asked me if I had heard of JL Audio. Why yes, I had just been studying JL Audio the night before, but unfortunately could not afford the Gotham subwoofer listing at $15k. Henry pointed me to a much cheaper option at about $1k each.
We listened to the JL Audio D110, with a low pass at 40Hz, and I was really blown away, because this little subwoofer was putting out way more than seemed possible from a small sub and the sound was very tight, not boomy at all.
My comments: Henry, are you absolutely sure there is not another sub on? Really that is the only sub on? That sub is way to small to produce that kind of power. How is this possible?
Henry explained that JL Audio designed smaller subs for vehicles, and has moved that technology into other areas.
I was sold. I bought two subs to ensure I had plenty of dB level, which after further review in the studio, was correct at 50% volume. The results in the studio were just as amazing, and I am still breaking them in. The low end sub sound is very tight and true, not boomy at all, just what I need to translate my mixes.
Two is just right for my application and I have placed directly below my speakers. No delay, no phase issues, just very tight, punchy and controlled. When there is too much bass, it sounds like too much, it sounds true to the mix, which is just what a studio needs to translate mixing and mastering.
About $1k each and I needed two at 50% volume. See room specs above.

JL Audio D110: 10-inch (250 mm) Powered Subwoofer
27 - 111 Hz (±1.5dB)
-3 dB at 25 Hz / 118 Hz
-10 dB at 21 Hz / 143 Hz
Capable of peak-to-peak excursions well in excess of 2.7 inches
Active 750 W RMS
Width (W) 12 in / 305 mm
Height (H) 13.4 in / 340 mm
Depth (D) 15.86 in / 403 mm

Three weeks and still loving these subs. To be truthful 50% volume is slightly too high, but I like feeling my pants legs moving with the beat and plan on keeping it there. It just feels right or just enough wrong.

Peace!
grega60438

Jl audio makes great subwoofers. the w6's and w7's are some of the best subs I've heard for car audio. Every time I had a JL Audio sub I never felt like I needed a better subwoofer. They are as good as it gets I'd say. I've used cheaper subs and never felt the same way about my bass. Using a modest JL audio w6v2 in my car really helps me get my mixes translating from out of the studio. I hear the bass differently in the car. It gives me a great reference on how balanced my song is and how much energy my mix has. If you can integrate their home theatre subwoofers into the studio more power to you.

we are JL Audio dealers but have yet to sell the D110...good to hear of your success.
Most of our studio sales are the f212...which is incredible. One high profile client added 4x e112...as budget was a bit tighter.