@blackiridium re: "So the ATC and Proac models wouldn't be loud enough?"
Those pesky Laws of Physics again. If you review the calculations I made, you need a speaker with a peak output capability of around 114dB. The other wise great ProAc D2R is rated at 88.5 dB sensitivity and 100-150W power handling. OK, 100W is 20 dBW, 150 about 21.5 dBW. So 88.5 plus 21.5 = 110 dB peak output. At the estimated listening position of 4M you lose 12dB of level due to the Inverse Square law. 110-12 = 98dB Peak level. allowing the 12dB Average to peak level, leaves us at 86dB max listening level before the system will sound strained.
The also otherwise great ATC is described on the ATC website "The SCM20PSL is ATC’s flagship 2-way stand-mount loudspeaker and is the ideal choice in modestly sized rooms, but where performance cannot be compromised." It is rated at a peak out put of 108dB per pair from 80-20Khz, and -6dB (peak 102dB) from 55Hz so their numbers are even lower than mine. and your assessment regarding being light in the bass is correct.
The point here is this: a 6" bookshelf simply can't move enough air for realistic playback levels of practically any music type in a room of your size. An 8" woofer will give about 3dB more output, and the JBLs are engineered for maybe 3dB more output than most.