smaller speakers for critical listening?

You certainly are not going to get much bass from small speakers.  Only way to live with them would be to add a pair of REL S2 SHO subwoofers.  However, add the REL's to a nice pair of towers and you will enjoy music a lot better.  I certainly wouldn't even consider small speakers if you want to hear bass.

@larry5729 My 20" tall Salk SS 6M's are listed as 35hz and I gotta tell you, they really get down there. Front ported, larger than average monitor -- when I add the sub, well, it helps, but not nearly so much that I feel I really really need a sub.

The new Sonus Faber Electa Amator 3's should be on your short list.

@ verdant audio, fantastic post and you have the great ability to take the reader to a place of understanding. 

@northman --

I know that may be a ridiculous question; of course one can sit down with Radio Shack speakers and engage in serious listening, and of course the experience is subjective for all of us. I’m actually asking for subjective responses here. If your goal is a system for critical listening, do you think smaller speakers can do the trick or do you need the bigger soundstage and depth that can come with floor-standing, planar, or electrostatic speakers?

Interesting question. In some vital respects I’d go so far to say that a smaller, typically stand-mounted 2-way speaker (a single full-range driver per channel as a singular point source with no cross-over would, in principle, be a better example) is a reference that I hold my current set-up against. As a friend of mine pointed out to me not long ago after listening to a pair of (the original) Snell J speakers driven by a Sugden A48 integrated amp and a streaming source, he’d found that listening experience to be telling of what had originally formed the basis of his endeavor into audio reproduction, and to which I agree; the simple, coherent and inherently musical presentation afforded by these components was spellbinding, and an instant reminder what it was and still is, at its core, all about. Any smaller 2-way speaker wouldn’t do as in this case the old Snell’s had a beguiling ability to capture the listener with said qualities, but it goes to show that added complexity - a common and often necessary "component" with bigger speakers - has its price and that, by and large, working with more cross-over points, point sources and different drivers is in a sense an act of damage control. Maybe that’s why my friend’s current main speakers are still a 2-way design, albeit scaled up in size as a different design and augmented with a pair of subs - as is the case with my own set-up. Scaling up a smaller 2-way design in keeping it 2-way isn’t without its challenges, but once we go there size in itself as well as the different design choices dictated here comes in handy as a primary physical factor that’s indispensable for anything approaching authenticity in reproduction. One could, as has been recommended by poster @atmasphere augment smaller, again, typically 2-way speakers with subs (less than 4 of them would also do, and if not they needn’t be Swarm per se - just to dodge the business affiliation at play here), and it would be a viable way to maintain the qualities of simplicity of smaller speakers while seeing an uptick in scale and possibly other areas. Myself though I like to keep the smaller and simpler design untarnished to act as a reference in that regard, and instead take the leap into scaling up the whole of the package. Where I would venture into more than 2 cross-over points in the main speakers is with the Synergy horn speaker design invented and patented by Tom Danley of Danley Sound Labs, which effectively (and successfully) emulates a single point source per channel in merging the response of several drivers mounted at the backsides and center of a shared horn flare. A brilliant design, really.