Millercarbon has it right - the low extension depends more on your room than you would think.I do not see yet the question answered though: can a single driver speaker reproduce an orchestra?Yes it can. Fostex FE204 Voigt pipes I built can. It has particularly truthful piano reproduction, the best approaching a real piano I heard so far from speakers.
How can it be?The brain makes sense of the fundamentals ONLY when the upper harmonic spectrum is correct. With single driver speakers there is a flawless continuity with the upper harmonics, so even though the 26Hz fundamental is already quite rolled off, but you have the 52Hz & up harmonics PERFECTLY lined up, so your brain will reconstruct the 26hz fundamental that's not physically audible, and the lowest note will be there in absolute harmonic richess, although lighter in weight (versus the heavy handed, but dried up 26Hz that you get from a powered sub or additional base driver that has different resonant characteristics than the upper drivers, hence the tonal spectrum goes south.)
Audio technology is not perfect, each solution has advantages and disadvantages. People assume that adding more drivers is a perfect solution, however, it has its own compromises.
Also, I'd like to add that I have not heard any commercial full ranger that comes anywhere to a full range experience, although I have not heard any properly set up. (With FR speakers proper speaker placement & amp matching is beyond vital.) Improper FR speaker set up: shrill and annoying sound. Proper set up: listened to Beethoven IX on them right after listening to Bethoven IX with live orchestra, and the FR gave a better experience than the live one. Just a thought... FR can sound great. Also, I heard the best timpani on these FRs. ;). They are not brutes, don;t expect titanic crashing the iceberg and peeling your plaster to strike massive egos. Think base that has 3D definition, kettle drum that you literally can see in your room, with the skin vibrating and the waves washing over you and stopping your heart for a second - not from brute speed, not the sound-trying-to-rape-your-room, but the intense speed that defies what we expect from recorded sound. FR drivers can do more in the base department, because the ultra high sensitivity gives them the dynamic / speed edge. (Need I add: 95dB and higher sensitivity FR...)
Bruce Edgar had a FR speaker made with Lowther 6PMA, maybe you can find one around... (he made very few though.) That's an outstanding FR!!!! Practically no Lowther shout, yet all of the Lowther speed and best low extension of any FR I heard.
