Zam -- to generalise the issue: when I want s/thing to rock, I mean (among other things) I want to hear and feel the staccato, the sudden, the hard & the soft sound (whichever the rock player intended) -- and of course some of the impact energy contained in bass & percussion. This stands for rock music.
For rock you need the impact and the sudden acceleration & precise breaking (to use an automotive analogy).
In classical, restitution in harmonics, perceptibility and duration, and phase & timing (among other things) are absolutely necessary.
Having said that the applications (i.e. systems) MAY be different in both cases you ideally need ENERGY to emanate from the speakers.
To all intents and purposes, the most acoustic energy that can be had today will come from extremely sensitive speakers, i.e. ones that produce the most spl for each unit of power fed to them...
Failing that, you have to choose very powerful amplification and spkrs using very robust drivers that can take power abuse (i.e. mostly pro) .
Flimsy, designer, hi-end stuff ain't going to do it (or will typically cost more than a house + swimming pool)
And a final point: in an attempt to play, say, 89-92dB speakers "louder" rather than at whispering level, the loud musical passage is very likely to produce distortion and eventually blow one of the anaemic mid-woofs used in many spkrs. Why? Because to get the impact of, say, Mr Pastorius' slamming his bass chord in full musical transcendence (worse still, take a BBC recording of J Hendrix) you may feed the drivers with a gazilion watts for a few milliseconds even more, and this will be recurring -- you're listening to music after all...
They'll blow or if not, complain.
Cheers
