Near Full Range, Highly efficient Stand Monitors?

even many bigger boxes don't really go into the 30's

I have been surprised with the bass out of my Dynaudio Special 25's. Stereophile measured them at 89 db/1w and the impedence is around 6 ohms. They say 15w for a small space. I have to attenuate my preamp due to excessive volume.

See thread above titled: "Pros and Cons of built-in amps?"

Hoffman's iron law states that the efficiency of a system is proportional to its cabinet volume and inversely proportional to the cube of its cutoff frequency.

If you could make a bookshelf speaker 95dB efficient at 60Hz, maintaining the same efficiency at 30Hz would require 8X the volume which you could get from doubling each of its measurement.

You'd really be better off with a floor stander that has the same footprint (it can pickup nearly 6dB from the floor) or separate sub-woofer (which can have boost from operating into a smaller space and/or a big amplifier to compensate for the small box).

Dear Drew, True in most circumstances until you discover a properly designed transmission line and flat piston driver. Manufacturers tend to ignore such a complex implementation in favor of ports and infinite baffles. These are much easier and cheaper to make and are what the public are accustomed to expect. Subwoofers are now popular with the home theater crowd but for those of us serious about our critical listening habits they are too difficult to integrate properly into a seamless whole with disparate components and untreated rooms.