The Perfect Speakers for Jeff Rowland Concerto Int

I have no idea! I have not heard the Concerto, sorry if I gave that impression, I owned both the Concentra I and the II models. Best to go demo the set up or better yet see, if your dealer will set it up on a Friday for you to audition over the weekend in your own home. They did that for me!
Good luck!

For your reference, Avalon , Wilson w/p , and PMC could be very suitable for Jeff Rowland Concerto Int

What's Jeff Rowland say?

On the Rowland site, they say they will not recommend associated equipment, but you can always ask!

I am using the Concerto with JMLab 1027 Be's and it is a very nice combination, using Ayre CD player and audioquest cables (cheetah and volcano). I get the idea that cables might be pretty important with this amp, because the sound is noticeably brighter when I have my power meter connected, which hooks up with 3 feet of wire. Not a lot brighter, but I can tell the difference. By the way I auditioned the Ayre K5 and V5 (the current "e" version preamp & amp) with the Ayre interconnects & the Rowland was considerably better.

Not at all thin or bright - beautifully balanced in my system. If anything, it seems like almost every recording is listenable, no matter how badly recorded. That bothers some people, but it is better than being too "honest".

I have been using the Concerto Int. amp for about 9 months now. The Concerto is the most musical amp I have owned. Using with the Ayre C5xe, SF Cremona Auditors and REL B3 with PS Audio P500 pwr plant and UPC200 pre-conditioner. The speaker cables and interconnect are Cardas Golden Cross while the PC are all Cardas Golden Reference. The Concerto is extremely efficient and can run off the P500 with ease. This is the most musically satisfying system I have heard to date. Has the right combination of warmth, dynamics, detail, timing, sound stage, imaging.....on and on and on.. I've been smitten.