As it happens, we have an overlap in musical tastes. Only the night before you posted about Joplin, the Airplane, Cream, etc., I had listened to the first two of a three-disc Joplin set. There are a few tracks with just Janis and Jorma Kaukonen recorded in his living room, probably with a consumer grade ¼" reel-to-reel and some really cheap mics. They didn't even ask someone in the room to stop typing! Nonetheless, the Omegas' musicality came through; the tracks were listenable. Not sure that would have happened with the Acoustats and a big SS amp.
After I read the post where you mentioned the Airplane, I cued up "After Bathing at Baxters" and took a few notes on how the Alnicos were presenting Jack Casady's bass without subs. I think some specificity helps here when discussing the tone of a bass instrument, rather than Bass as a generic audiophile term. Although Jack dialed in a very deep tone on "Martha" and "Wild Thyme," I could still hear the percussive effects from his distinctive right-hand technique. (Incidentally, during the early years of Hot Tuna, I got a close-up look at that remarkable technique when I somehow managed to wrangle a spot just off-stage at the Fillmore East. Never seen anybody play like that before or since.) On "Rejoyce" he's using a woodier tone that might mark the beginning of the mods Alembic was making around this time on his Guild Starfire semi-hollowbody. There's some intricate interplay between bass and the piano's bass register and the tone of both instruments remains distinct so you can follow both lines, even when they converge. My copy of the album includes some bonus tracks, including a "single" version of "Martha." Jack's attack here is so percussive and the sustain is so strong it almost sounds like tabla.
You bring up an interesting question about hearing vs. perception of low frequencies. I read recently that when it comes to tones below 200 Hz, what's actually happening is that we're hearing those overtones I mentioned earlier and from that our brain imputes the fundamental tone, which we can barely hear.
I think it's important to remember that the subwoofers themselves are also putting out overtones according to the subs' own character, even if the signal's filtered so the subs are only receiving a signal below 150 Hz. The overtone cycle of the sub is what my friend John was referring to when he said that his (non-Omega) subs sounded out of tune. Louis on his web site is largely addressing timing, which is another issue with a lot of subwoofers. And I wouldn't be surprised to learn that having the the subOMEGAs fire down at the floor helps dampen the overtones.
I think there are two issues here: one is what we have in our heads as a live music reference. I listen to a lot of classical chamber music, jazz, blues and country from the ’30s onward to the present and I had the great good fortune of actually hearing, on a weekly basis for several years, a rhythm section of masters from the acoustic era: drummer Barrett Deems had been in Louis Armstrong's small group for more than five years in the ’50s; bassist Truck Parham (
http://www.nytimes.com/2002/06/23/nyregion/truck-parham-91-jazz-bassist-for-7-decades.html) could still drive a band in a large saloon without an amplifier and he had a rich tone that varied with each note of a 4/4 walk. Armstrong once said if you had to ask what swing is you'd never know, but if you heard that band and couldn't figure out something about swing, Jack, you're dead.
The second issue is economics. A number of queries on this forum come from people who can afford only to buy a pair of Super 3is and subs or Alnicos and no subs. A lot of people have a hard time getting their head around the idea that one driver can take care of the entire frequency range. But at least for some people, in some rooms, listening to some kinds of music, subs would be extraneous and may even skew the frequency balance and muddy some of the rich tonality that Alnicos can offer. Unless you have an un-limited budget (and maybe even then) everything in audio is a matter of managing trade-offs. Subs give you an opportunity to augment the lower frequencies, at a cost of intonation and, perhaps, a bit of fine tonal detail that probably wasn't there anyway on electric bass recordings. That's a great audio trade-off: you're giving up something that doesn't really matter to you.
Just in case it needs to be said, if I were to buy subwoofers of course they would be Omegas. And some day, in a different listening room, I might. My PSB desktop speakers were designed with a matching sub and the whole package is quite musical if miniature.
What the hell, I could always turn off the subs when they get in the way.
