Right after the graph you pasted, Butterworth says: "The CEA-2010A results for the Nano 1 are lower than most of the subwoofers I review, which of course are much larger. However, compared with the few subs that play in its niche--i.e., ultra-compact models designed for high performance--the output is impressive. For example, the Sunfire Atmos subwoofer, which is slightly larger, delivers, by my measurements, a 40-63 Hz average output of 108.4 dB and a 20-31.5 Hz average of 81.8 dB. Compare that with 109.2 dB/86.0 dB for the Nano 1."
The Sunfire Atmos is currently $1200 at Crutchfield and Newegg. I didn't post to be the Nano's defender or even to imply it can compete with a "real" subwoofer, I'm just saying that it seems to compare favorably with others in its class. If what you're saying is that that class shouldn't really be called "sub" woofers, I can't say I disagree.
As for your comment about bookshelf speakers, currently in a vacation house I'm using an ancient pair of these as my main speakers for music:
I'm actually not unhappy with the way they sound other than no output below 80 hz. I either need a tiny subwoofer (WAF) or if you could recommend a very small (and inexpensive, like less than $300/pr
) bookshelf speaker that would give me some good bass and eliminate the need for a sub, I'm all ears. Thanks!