Are the JL Fathom subs really that good....

If you place one sub in the same plane as the main speakers you can't tell where the sub is, assuming a 60Hz 12db/octave crossover. If you place the sub closer or farther from the listening position than the mains you may have to adjust the arrival time (which is tricky stuff).

Bass sounds are omni-directional, but in a car the shock waves through the structure of a car aren't, and that's why you can tell where the sub is. Even in a house I can tell that the bass is coming from somewhere in front of me, but I can't discern the sub's position between the speakers. Or even that it exists.

Still, I have to agree, two subs are better than one, and optimum positioning seems to be one near each main, assuming that's a good position considering room modes. (It often isn't.)

Bizango1, if bass is omnidirectional, and that's a physical fact below 100Hz, then by definition you can only localize a source by means other than listening. :-)

Bass is a funny phenomenon because you feel it as much as you hear it. Your sense of touch does not work like your ears. Hearing is logarithmic. It takes a doubling of power to produce a small difference in apparent loudness levels (3db), yet as everyone knows a doubling of mechanical force feels like a doubling of mechanical force. So a 3db increase in sound level at 40Hz can result in a feeling that you've really turned up the bass, because you're feeling it.

Regarding JL subs for 2ch audio, the only thing that kept me out of an F212 was that it didn't have a high-pass filter for the woofers on the mains. All of my demos of various subs I did revealed that unless you use a high-pass filter, preferably at about 60-80Hz, the bass sounded muddy and over-blown. Yes, I know this is a highly controversial point. Some folks like that bass-heavy sound, but not me. I looked into a Bryston 10B-SUB to perform bass management, but F212 + 10B-SUB = big bucks. I just got a Velodyne DD18+ instead. A pair of SVS SB13-Pluses are also a good choice for music, and include high-pass filters.

Chris, I don't know how big your room is, but at a distance of about 12 feet from the sub I can't tell where it is.

Too bad we're not all in the same neighborhood. Hearing each other's systems is great fun, and talking is better than posting.

Nvp, I agree time alignment is only one factor, and not always a big one.

Interesting. Since your post, Bizango1, I've more carefully listened to see if I could tell where the subwoofer is in my room. I have to admit the results inconclusive, for two reasons. First, my sub is positioned about midway between my main speakers (though not exactly midway), making the sub more likely to appear blended. Second, a lot of recordings are mixed with mono bass. Perhaps most recordings. This, of course, means that a centrally placed sub will blend even better. So it possible that the only reason I can't tell where my sub sits is because that's how the bass would sound even if the sub weren't present.