Why the obsession with the lowest octave

"Having a tweeter than goes well above the audible frequency range just allows a better reproduction in the range that you can hear"

Not necessarily - it might distort more at few kHz range.

Of course, having the ability to deliver very deep and powerful bass is a big advantage. I just think that, given the usual constraints of size, power requirement, and BIG dollars, there are tradeoffs involved. There are tradeoffs for ANY aspect of speaker performance. The choices one wants to live with depends on taste, type of music, etc.

For example, unless one is talking about a very well engineered active biamp or triamped system, trying to achieve really deep bass using low-powered tube amplification is extremely impractical (look at some of the as-big-as-a-room bass horns of some Japanese systems). But, if you have heard what a really good SET amp can do, trading off some bass capability might be your preference; it is a matter of taste.

I actually have speakers capable of reasonably deep and powerful bass (it has two 12" drivers per channel), but, my chosen amp really cannot deliver room shaking volume. What this combination offers is doing almost everything else right at a comfortable volume level. It is a big system, with a "big" sound, just not a super loud system. I don't use it for home theater, so I don't need things to shake when it plays.

I have heard many speaker systems with full range bass capability (e.g., Wilson MAXX 3), and certainly they do deliver in that respect, but, I have heard few that, on balance, I would prefer over what I have (and those were also not particularly big in terms of bass performance).

Can't say for others but I "get" the harmonic content from mathematics. You guys are all free to believe what you want and setup your systems any way you see fit.

So Dan_Ed, how about an explanation of your mathematically derived harmonic content?

A device called a "Subharmonic Synthesizer" can be used to create tones which are not there but which "ought to be" based on what is there. It can sound better than trying to record real tones in the extreme low range.