Narrowing the field a little. Not interested in horns, electrostats, personal (vs established company) designs etc. Speaker must sound good for both 105 db orchestral and 70 db chamber.
David,
Ok - let me see - no horn, no panels, no boutique designs.
If you mean 105 db SPL continuous then I'd recommend that you need at least an ATC SCM 50ASL (like Gordon Holt who likes classical) and possibly a JL F113 sub or two depending on room size and placement - IMHO.
Why? Because if you are listening at 105 db SPL (and sitting a typical 2 meters back) then this is 111 db SPL continuous sound and you will also need plenty of headroom (or else it will sound strained and dull with most non pro dynamic speakers and you ideally want an effortless sound). If you have a bigger room and sit a little further back then you probably need an SCM100 or bigger, as well as the sub(s).
The 3 inch midrange in the SCM50 is on the right while the bigger 3" dome for the larger SCM100 to SCM300 range is on the left. Why a photo? because a picture is worth a thousand words - this 3 inch driver has a bigger magnet and bigger diameter voice coil than you see on 99% of all woofers and subwoofers...there is a reason for this and at 105 db SPL at the listening position you will hear that reason (without a horn you will definitely need a design with big motors). It has a wide "waveguide" to control dispersion (this is not a horn).
An extremely dynamic pro driver three way like ATC or PMC can certainly handle your needs without the least hint of strain and also play at 70 db with chamber music with no problem with the same accuracy and balance. This is a key reason these speakers are popular in mix/mastering. Note that your ears will inevitably suffer the usual Fletcher Munson loss of hearing sensitivity to bass frequencies at low levels - so it will not sound quite the same but it will not be the speaker fault - just use some loudness or bass tone control if you want a fuller sound at very low levels. Usually the mastering engineers take care of this for you - rock and Mahler sould be mixed thin in the bass so it sounds best real loud (as it is when heard live) - the opposite is done for chamber music.
FWIW - I don't hear significant differences in IC's, cables or most CD players - perhaps I have tin ears from listening too loudly!
Good luck and happy listening - just don't play it too loudly for too long as it is not good for your hearing.