Bob, for bookshelves and no sub I'd suggest the M22s. The bass extension is actually slightly lower than the M3s and I found that it was adequate for most music(not pipe organ)without a sub. Before I got my EP500 and had a much less impressive sub with the M22s, I'd often listen to music without the sub and got good in-room response to about 50Hz and much weaker, but still usable response to about 40Hz.

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Enjoy the music, not the equipment.