Spatial Audio M4 Turbo S. Is its design competitive with other baffleless speakers?

@lowrider57 Yes, that’s me.Thanks for the shout out to my blog, and @sunnyjim,  I hope the information there is useful to you. The blog has both my original review of the M4 and my subsequent review of the M3 after trading up. I love both of them and think they are great. I will also say that with the right amplification – I am moving out toward solid-state, myself – the image beautifully and throw a gargantuan, immersive soundstage, if you’re into that sort of thing (which I am)!Hope this helps. 

Haven't heard of them.

Their concentric driver looks identical to the one used in my Emerald Physics KC IIs (AA/USAudiomart), which I am selling only because I am moving up in their line to 3.0s. Mine have a WireWorld XO upgrade ($4500)

As I read further into the review, I agree with the additional complexity of DSP: the KC11s are passive, and do not require \ biamping (but you can if you desire).

FYI, I find speakers, especially baffless ones, sound best with zero toe in

Clayton designed Emerald Physics and then started Spacial Audio. 
I was oh so close to buying the Spacial's, but they're too large for my room.

My buddy has a pair of KC IIs in a small apartment and they sound great They're barely 42" tall from the bottom of their bases, without iso devices, which I highly recommend. Having owned Magnepan 3.5Rs and Accoustat 2 + 2s , the KCIIs are a super bargain