when is a speaker considered full range?

As frequency increases (towards 20 KHz) and decreases (towards 20 Hz) the loudness decreases. The range of a speaker is usually stated as the frequency where the loudness is decreased (rolled off) by 3 dB compared with loudness at a reference frequency of 1 KHz.

Missing from this definition is any mention of the loudness level at which the measurements are made. Many small speakers claim "full range" response (down to near 20 Hz) but this is only true at relatively low volume. My custom subwoofer system consists of three 15" drivers and three 12" drivers, and it only begins to feel like a pipe organ with all the stops out.

Shadorne....I'll grant you that we can get along without 12KHz -20 KHz (oh to be young again), but for some kinds of music there is indeed signal down to, and sometimes below, 20 Hz. To get it with any kind of power you need lots and lots of big drivers. A pipe organ, for example, is felt as much as heard. However, if this lowest octave is missing in the reproduced sound it can still sound good. Untill you hear the recording on a system with extreme LF response you don't know it's missing.