Comments please on: NAD M23 vs c298 vs. other newer Class D

My final main speakers were designed, built, tested, and tweaked using this family room as my final test bed.

That’s a key point. You *built* your speakers for that room. That’s a kind of "treatment" in my opinion, though I am not sure how you built it for the room other than back and forth trial and error. That's a good method but it helps to also have information about nodes, reflections, etc. by measuring. But if you haven’t measured and it sounds good to you, that’s important. Could it sound better? Quite likely, but if that can't happen, well it's best to find a practical life-balance. It's not "audiophile-ideal" but it is "life-ideal."

For me, getting into the audiophile hobby has meant playing around with tubes, gear, cables, isolation platforms to see what changes they make. But I get extra confidence in playing around with those minor changes knowing that the largest factor, the room, is dialed in. I’d compare it to tasting different wines -- I prefer to judge the differences between a merlot and a cabernet without having a strong breath mint in my mouth at the same time. I can tell some differences between the wines with a breath mint in my mouth, but I would prefer not to make distinctions with additional distractors in the comparison.

@hilde45 ... I’d compare it to tasting different wines -- I prefer to judge the differences between a merlot and a cabernet without having a strong breath mint in my mouth at the same time. I can tell some differences between the wines with a breath mint in my mouth, but I would prefer not to make distinctions with additional distractors in the comparison.

What measuring equipment are you using to measure the taste of the wine?  

Tongue and Taste = Ears and Hearing, LOL. :) 

@decooney LOL. Yes, the simpler the analogy, the more perfect the correspondence! Actually, I like to compare gear while running an electric train set in the background! After all, I'm still using ears and hearing, so what's the difference? ;-)

The listening "differences" and preferences can vary greatly - is what I've concluded. @hilde45 the real truth I follow now is that I don't trust anyone else's ears or their measurements any more. None of that makes a hill of beans difference to me any more.    

We have a local NorCal AES group who still gets together once in a while, and I don't go any more like I did a decade ago. More than once I concluded listening in groups of 5 or more audio heads, people all have different preferences.  

Measured rooms, non-measured rooms, whatever the case have heard more sophisticated systems set up by others I really did not like very much, at all, and other simple systems with modest setups that sounded really good to me.  

We have a local dealer in business more than 56 years now. Had a small 10w integrated tube amp set up with simple 2-way speakers, simple CD player. Sounded absolutely beautiful, engaging. One of his lower cost systems on display that was nowhere near the level of sophistication of systems 5x the cost sitting next to it. Nothing special about the room or damping or anything like that.  Nailed it.

Thought to myself, maybe really good system matching matters most and it's not always about how much we spend or finding the perfect room for things.  

Getting back on track, @hilde45 given your different speakers and room testing, it would be fun to try the NAD M23. Reading up on it indicates a quiet noise floor and possessing a nice neutral sound and presentation. I'd like to hear one as well some day.