So the first L12 I received from Rythmik was defective, but they have great customer service, and I've had the replacement since Wednesday. I didn't really have a chance to put it through its paces until last night. Now that I have I figured I'd post some impressions here. Not that I'm telling you anything you don't already know, but maybe someone who is on the fence about this sub would find my comments useful.
I have done no calibration or dialing in. I just plopped it down in a convenient spot, set the gain knob to 50%, and switched my front speakers to "small" in the AVR. I plugged into the LFE input as recommended by others here. I will eventually run Audyssey, but it wasn't a good time for it last night (too much noise in the house), and I wanted to play with my new toy.
With the addition of this sub my 5.1 system is complete. The other speakers are KEF Q750 up front, Q100 in rear, Q200c in center.
I am impressed by the way this sub blends in, even with zero calibration. It doesn't blare or boom, it isn't heavy or bloated. It just adds low frequencies into the mix, and I would swear the bass was coming from the speakers and not the sub. I had to put my head next to the sub to make sure it was working.
Started with some music tests. First up was The Kraken off the Pirates 2 soundtrack. The difference on this track was subtle. It sounded and felt darker and more menacing, which is probably the composer's intent. And the bass drum "heartbeat" sounded articulate and sharp.
Next was Sia's "Cheap Thrills". This track is pretty much all bass, and it shines with the L12. Ironically, hearing this track's thrills was not really super cheap. Last thing I listened to was "Familiarity" by Punch Brothers. That track has a very deep bass line played, as far as I can tell, on an upright bass, and it was far more present then I'd heard it before.
But the real test is home theater, right? That's what everyone says you need a big beefy sub for. Even Rythmik doesn't think the L12 is best suited for home theater. On their product page they say it's suitable for "moderate home theater use." Well, I have a copy of The Force Awakens that would tell whether "moderate" was enough for me. I put it in, switched the sub to "Low HT" mode, and cranked the volume as loud as I would ever want a movie to be in my home.
The L12 didn't seem to break a sweat keeping up. Ships, blasters, and explosions were thunderous. Then Kylo Ren pulled out his light saber, and I had to pick my jaw up off the floor. My hat is off to the audio engineers who created that sound, because holy crap
does it sound amazing. The L12 makes it sound as frightening as it was intended to be.
At one point I walked down the hall to use the restroom, and I received another surprise. I could still hear the subwoofer. When you're sitting surrounded by KEF loudspeakers doing their thing, the subwoofer blends into the rest of the sound and you don't notice that it's a separate thing. But with the higher frequencies attenuated by walls and distance, I could really hear what the sub was doing for the sound.
So, I guess "moderate" is all I need. The L12 is probably capable of more output than I even want. Based on one evening of use, I'm super happy with the cheapest Rythmik, and wouldn't hesitate to recommend it to others.