I hope your thread gets some helpful input. Like you, I have considering going with smaller speakers and have looked at the speakers you mentioned. I have some older B&W's on stands for LR speakers and between the speakers, the tv, and some furniture that wall seems somewhat crowded.
I have read some good reviews on the Orbs and Anthony Gallo's, but I haven't been able to listen to a pair. I saw some small Jamo's (sp?) at a MHT store, but was unable to listen to them. I assume the Cambridge speakers you are considering are in the Minx line?
Orb's tag-line is, " Small speakers for smart people. " That in itself would make me stay away from that manufacturer since it is so Bose-like. LOL
Denon AVR X7200WA, Emotiva XPR-5, Emotiva XPA-7, Sony XBR 75" 850C, Oppo BDP-103D, Roku 4.
DefTech BP7000SC (L/R), CLR3000 (C), SM55 (FH), UIW BPZ/A (SB), UIW 75 (TM).
JBL L7 (Sur), EoSone RSR 350 (RH).
PC 2.1 setup. Emotiva Stealth 6, SVS SB2000 sub, Emotiva DC-1 DAC.
We have a thread you may want to browse at your leisure:
I haven't heard the other two, the Jamo's mentioned above aren't worth listening too if it's the spherical speakers he's thinking of. Perpendicular on that thread I believe had the orbs and could tell you what to expect there and how they compare and contrast with the Minx. Otherwise as far as the Minx go, the Min21's are a very nice speaker. Very good clarity and dispersion which produce a sweet area instead of a sweet spot for listening. They are a very musical speaker because of the detail they provide without being harsh or analytical sounding. The dispersion with the clarity and detail that goes with it shines when it comes to dialogue. However, the increasing/decreasing volume has a lot to do with the sound mixing for movies and some tv shows.
The Minx are far better than the RC-Micro's. You aren't missing any low end compared to the Micro's 150hz and the quality of sound is so much better with the Minx.
How small does it need to be? You are always giving up some performance with small speakers, smaller drivers just don't have the output, dynamics, sensitivity or low frequency extension of a larger speaker. You will benefit from a two-way speaker as compared to one full range driver. Here are some small speakers but might be too large.
Genelec G One or G Two
There are many small 3-4" woofer with a tweeter designs or for a little smaller a coaxial design like Tannoy or Kef. Going smaller than this is a big compromise.