What are the specs of a full range speaker?

Muralman:"all I know is most systems are truly deficient in the 20-20Khz range(meaning problems in qulility of reproduction of the original source)..I don't knwo why anyone would want to perfect what they can't hear, before they (first) get right, what hz's they can actaully hear". Agree, before we run after the 20hz-30hz/20K hz-25Khz, first how does the speaker reproduce the 40-18K hz?
For me its more important taht a speaker offer a seamless image in the meeting of the bass/mids/highs,, that it is to get at the 20-30 and 20Khz+ range. Actually 30hz is my bottom range I'm interested in. I alreday have a speaker in mind that fits the characteristics I'm looking for.

Goroi- I was referring to speaker systems of any kind, not just single driver systems.

Sogood51- I like your "room lock" and "room shudder" concepts.

Newbee-The passage says "reaches down into the 30s WITH SOME WEIGHT". Is that meaningless? The meaning was clear to me but maybe it didn't translate well.

Pbb- Thanks for taking this where I had hoped it might go. What use is the inaudible? I personally feel that the whole absolute sound model steers us away from a relaxed and pleasant music listening experience and causes us to grip our chairs and squeeze the last note out of our equipment.
Why are so many of us so obsessive?

Inaudible content on the low end can be detected by the body because it shakes the floor, ceiling, walls, etc.
How would we detect inaudible high frequency content?

For me above 15.5 Khz I hear nada....so I would agree that linearity in higher frequency response in a system is not very important to me at least above this level.

I respect that some can hear up to 20 KHz and when I was younger I could hear somewhat higher than my limited upper range today... so it is relevant.

Above 20 Khz, however, I have a hard time accepting there is any need for a system to reproduce these...maybe my dog appreciates it.

Low frequencies seem audible somewhere between 15 and 25 Hz to me...not that I don't hear something lower but that I suspect the sub excites vibrations in the walls which may be principally what I am hearing or feeling (some of these excited vibrations undoubtedly include higher harmonics and rattling which are clearly audible and are really added "distortion" but they make for convincing effects in movies). I have not found that higher frequencies (above my hearing ramge) are capable of inducing lower frequency audible harmonics in the room...the sound or test tone just disappears for me.

IMHO, due to the range of my hearing and for the added distortions that ultra LF excites, extended low frequency response is more important than extended high frequency response.

Tvad, because the low frequencies can be felt through your body as anybody who has contact with a system playing super low frequencies will tell you. Only very few researchers believe that high frequencies are felt through the bone structure of the head. Anything that turns you on is all right as far as I'm concerned, but I still think that defining terms and agreeing on basics is too important a subject to always put forth the exceptions to any given rule or a way-out theory as being what should be given prominence in these discussions. Call me crazy!