Sounds like one needs to have a speaker that can reproduce the LF first.
Indulge my story. Way back in the good old days of 1985, I was looking for new speakers. My amp - a Jensen's Stereo Shop MOSFET Control amp of a Herculean 25 watts per channel.
I went down to the best (and most honest) stereo shop in the Bay Area - Century Stereo in San Jose. They sold the B&W line. 801s were the best speakers at the time, but out of my price range at $4000. The 802s were at the upper limit at ~$1800. The 802s had the reputation of being very wimpy and not playing bass and the 801s were known as "power suckers". I went down first just to use their electronics, and sure enough, it seemed as if you needed a few hundred watts for the 801s and the 802s were gutless. This with the best stuff from Macintosh and Threshold. OK, that's conventional wisdom, and it was borne out.
I went back, and got my little SCA-50 control amp. After some convincing, I got them to hook up the 802s using cut-up extension cords as speaker wire. They were all looking at this thing and telling me I was wasting my time. Fired everything up, and hey, now those 802s sounded pretty darn good, lots of bass punch now. The one guy was in there with me, he goes and gets everybody else in the store (this was a Wednesday afternoon so there was NOTHING going on otherwise), and they ended up amazed and half of them were planning on calling Frank later that day.
Then they got the idea that they should try it with the 801s. They had been driving them with 200-something watt Thresholds and they had all concluded that they "needed more". Wrong again. The wimpy little control amp drove them just fine at any sane power level. At some point, at a volume beyond where I would have played it, it appeared to start running out of poop, but that was 1/8 as much power as their "minimum requirements".
The moral is that if you have an amp that can throw the current to it without falling apart, it makes all the difference in the world how much bass you have. Speaker that "can't play bass"^H^H^H^H^H^H^H^H cant "reproduce LF content" all of a sudden CAN play bass.
Frank is correct about most subs would just makes LF noise and nothing more, I've heard many for them in the "home theatre" systems powered by the run of the mill active subs like Polk Audio or Klipsch, which has little to do with music in my opinion. I have no idea what's in those active sub amp.
My experience with subwoofers has been similar. The one case that I though it made a clear improvement was my old Ohm subwoofer in my buddy's system. I had the thing sitting in my closet for 25 years, and he bought a system with some teeny mains. I can't recall the manufacturer (I really have no idea what is going on in retail hi-fi these days, I never go to magic cable stores, er, home entertainment system shop, so I wouldn't even venture a guess) but they looked kind of like off-brand B&W 805s. OK, but quite limited bass output, and driven my some sort of ADCOM integrated amp of unknown quality. We hooked up my old Ohm subwoofer and it was pretty much the same issue that made me put it in the closet the first time, not much if any extension and heavy overlap with the mains, causing a huge hump in the response. HE liked it OK and left it as it was. A few weeks later he calls me and says the foam surrounds have all fallen apart. Not a huge surprise. I looked around and found that Ohm still supplies replacement drivers. While on the phone to get them (very reasonable price, by the way), we mentioned the other issue, and the good people at Ohm said they would include some port tuning that might help. We replaced the drivers, they work but the same problem persists. Then we stick in the port inserts, and WOW, great increase in extension, and virtually NO overlap. Good on you, Ohm acoustics. It wasn't as good in terms of definition as I would have liked, but it definitely added a good bass presence that was lacking before.
Note that these were PASSIVE subwoofers, that have a crossover inside, no amplifier, and not adjustable in terms of crossover frequency. I expect that you could almost always solve the overlap issue if you had an adjustable crossover and an active amplifier, but the definition still comes down to how good the amp is in the subwoofer.
Brett
