I'd say that 1/2 power above and below 260 odd Hz is about right. Definition wise I'm a bit more retro as to what's where, so if you take a 'traditional' 3 way system crossed over at 500 Hz and 5kHz then that's where I'd delineate the bass, midrange and treble. On the other hand, my own modern home system crosses over at 100 Hz and 6 kHz, so it gets harder to define what is a woofer and what's a midrange driver or tweeter.Another way to look at it is fundamentals versus harmonics and overtones; taking the electric guitar as an example the fundamentals run up to about 1280 Hz (the highest E note with 24 fret scale), though a 1280 Hz fundamental is also a 2nd harmonic of 640 Hz and fourth harmonic of 320 Hz and so forth.
In any event there's no question that it takes a lot more energy to push the bottom end than it does the top, and a good, if rarely used combination, would be a robust SS amp for the bottom end and a pristine 3 watt SET for the highs.