Speakers for First Watt SIT-1 amp

Both Zu and Spatial make high efficiency high impedance speakers. I have a horn-loaded single driver speaker system as well and have heard a couple of mid-line Zu speakers and in both cases, almost regardless of the pairing amps - tube, SS, low or high watt, they all sound somewhat congested at higher volumes playing complex orchestral music content, As much as they excel in imaging while playing more intimate musical genres, they don't seem to be suited for rock and/or western orchestral classical music. Just my experience.

That's just the type of music I'm having issues with.  Has anyone heard single-driver speakers that don't sound congested with busy music?

Hello ggking,
You have created a very interesting thread and I will add that you have what is considered a unique and well regarded amplifier. You have received some very thoughtful posts from Audiogon members who are quite respected on this forum.

For all the positive attributes of a single driver speaker they have a few acknowledged shortcomings (as do any speaker niche). Playing complex or "busy" music and particularly at higher volumes is one of them. David_ten mentioned the Cube Nenuphar a new speaker from Poland. It was given a stellar review by Srajan Ebaen of 6 Moons. com. I find this very relevant given his extensive experience with single driver speakers (including the expensive Voxativ from Germany).The Nenuphar seems to have reached a new level of performance in this genre.

Another option is the Coherent Audio speaker (Toronto Canada). This is a 2 way design with a very simple crossover, 95db with an 8 ohm impedance load that is reportedly very flat. Based on owner word of mouth and professional reviewer show reports it sounds fabulous driven with low power amplifiers. I suspect it could be terrific with your S.I.T.-1 mono blocks.

BTW in the 6 Moons review Ebaen found the Cube Nenuphar to sound superb paired with the S.I,T.-1 and S.I,T.-3 amplifiers. He gave a slight preference to the S.I.T.-1.
Good luck ,
Charles

Id vote for a Voxativ ...perhaps supplemented with  a REL sub.  They have a FIT model now with a 5" driver ... perfect for mid size rooms.  $5700 with the AF2.6 driver. 
FYI, I owned a FirstWatt F7 and my Voxativ sounded lifeless with it.  I almost opted to try the SIT3 but the reviews were meh.

ggking7, I can comment on my own experience with single driver speakers vs multiple. I listened to Lowther in fideleo cabinets for about 17 years exclusively. They are wonderful speakers. Great imaging, very dynamic etc. I have to tell you I don't miss them after trying the Tekton open baffle speakers. Again, it's not that the Lowther's were by any means bad, but the Tekton's took the system up a couple notches in regard to just about everything. The place the Lowthers better them by a small margin, is width of the sound stage. The Tekton however give me more detail (without anything close to analytical), speed, stage depth, & instrument presence.