First Watt with KEF LS50s

dbphd I would consider an integrated if that add any value for you even more than otherwise if a Class D integrated. I have Bel Canto c5i and have heard others like Rogue Sphinx and Pharoah and am pretty convinced separates no longer offer the same advantages they used to over integrated amps in terms of noise levels and distortion. The c5i integrated gives up nothing to the Bel Canto ref1000m amps I run in my main larger system in this regard. The next amp I get for that may well be a Class D based integrated amp as well something along the line of Rogue Pharoah or whatver the latest and greatest may be when that time comes.

Budget?

If an integrated what other features might be of interest? That’s a big factor there. Some I find of interest are built in DAC, phono, headphone amp and even Bluetooth.

Budget?

Also please remind if you tried the HAlo amp with this setup and if so what was the issue there? I would think that to be a very suitable amp in your case.

Though I am less familiar with it the Proceed would appear to be quite suitable on paper as well. I’d be interested to hear how that works out.

If not satisfied with either of these, then I think Class D is a very good alternative to try.

CRossing over at 80hz still leaves a fair amount of bass up to the low power amp and inefficient speakers. I’d predict sound with less impact or thinner than might be possible otherwise. If you check the audio frequency chart you’ll see upper bass comes into play quite significantly with most musical instruments. You could still well get into clipping sooner rather than later meaning distortion and/or rolled off dynamics at higher volumes. A smaller room would be best suited.

Bottom line is it may be "suitable" but less likely to be optimal.

Whereas two powered subs, ls50s and a high power and current amp would probably perform optimally in a larger room. Class D amps would be a great option to consider.

With no subs. ls 50s are better suited to smaller to modest sized rooms.

First watt is best for high efficiency speakers which kef Ls 50 is not. Crossing over high at 80hz will help a lot.  Could be suitable but probably still not optimal.   Use of subs will make for better results in larger room for sure. 

If the powered subs are doing the work below 80 hz my guess is it would be suitable.