Single driver speakers. Are they worth considering ?


I don't mean electrostatic. How close to a full range speaker can you come with single driver ?
inna
Currently running Fostex Fe208ESigma in free air with a NAD D3020 and sub. Also running Audio Nirvana 8" alnicos in free air, with a class D icepower ASX125 and sub. I listen at around 58-60db. Krall, Jones, Fagen, Lofgren, Davis, Clapton and similar music. Sold a Primare I30 to finance most of the above pieces. Best decision so far on my personal music journey. Cheers, gotta love this hobby
It’s all about where you’re willing to compromise. I have a diy 6.5-inch ported bookshelf speaker that I think sounds great — for what it is. The mid-range is just very sweet and the highs are good. But I added a subwoofer soon after. Looking at my speaker measurement w/o the sub, I’ve got a nice 100Hz to about 8 kHz spectrum. That used drivers costing $100 each, so not cheap-o but not fancy either, with neodymium magnet and a cast basket, so good construction. And I tuned them pretty carefully with acoustic stuffing and port size. Put on girl-with-a-guitar music, or “unplugged” Clapton or Nils Lofgren, or moderate-level jazz or combo, or chamber music or piano solo, and they do great, a real pure sound. And think about it — that’s a lot of great music! It’s probably about the time domain and point source and other stuff I’m not competent to address. Ask Atmasphere. And they were 95 dB sensitivity for the 15-watt class A amps, so a good team. But not as a do-it-all speaker, I’d say.
Feel the most famous single driver speakers would be the Bose 901. Yes they had multiple drivers but all to form a single driver in basic delivery. What was the quote “ no highs no lows must be Bose”. I did and still have a pair. Need an amp that had a power supply that could double as an arc welder to drive them properly. Sansui 9090 Them run through a eq to shape the sound by bending the wave form to an extreme level. Yes set up right and playing loud to an over served crowd they sounded good. Set up with a quality system in a listing room you keep struggling to try and hear what is in the music you know is there but you can’t hear it. I have never heard ZU speakers but they do have a good reputation and following——
I have an 8 watt 300B system (Wavelength Duetto), and single driver Stein Music SP 1.1 speakers.  I have very much enjoyed the Steins for going on five years (a record for me).  I cycled through many traditional speakers prior to them, and even during this period have scratched the itch to buy and try Devore 3XL, 0/93, Daedalus, and Audio Note AN/J. 

I do of course notice less bass response as well as a loss of some treble.  That is why I thought I might be able to improve upon them.  And for a week or so every one of those trials convinced me that I made a good choice.  Then, I put the Steins back into the system and very quickly decided that the Stein's presentation is more organic, realistic etc.  The immediacy of single driver speakers is very addicting.  For me they give me a "band is in the room" vibe better than the other designs I've tried.  Holger Stein is known for effective, natural and physics-based tweaks and his SP 1.1 design considerably tames any downsides to the design. Your mileage and ears may vary.

I just recently found a set of Musical Affairs speakers with natural wood cabinets and PHY Sag drivers, and am looking forward to my 2nd pair of single drivers!