Great post...thanks for sharing. I had a similar experience recently and was thinking about how to share the revelation. I believe you've described it pretty well. Up until about two weeks ago I was feeding my Lampi Baltic 3 DAC from my iMac using Qobuz and ROON. Connected via AQ coffee USB. Using my iMac with quad processors, SSD (no fan), ROON enabled (upsampling on), solely purposed as my streamer. connected to my basic AT&T router via CAT 8..and listening to the music coming from my system...I'd pretty much convinced myself that it was probably as good as it was going to get. And I mean that in a very good way...to my ears there was nothing really lacking. My personal test is 'do I want to hear just one more song' after doing 2+ hours of critical listening. And does the music just make me sit back and smile. And I did. And it did.
I'm not sure exactly what prompted me to pick up the phone one afternoon and make a call to my dealer to discuss streamers. I guess it was partially reading other posts on AG...as well as some personal experience having thought 'this is as good as it can get' a few times previously and having been pleasantly surprised otherwise.
First thing I told my advisor was that I wasn't sure exactly what problem I was trying to solve and that I was going into this somewhat skeptical having yet to read anything I could understand as to how moving a bit-perfect stream of 1's and 0's from one place to another was going to improve my SQ. We discussed streamers in general and long story short he said he believed there was noticeable improvement to be gained by getting a dedicated streamer...and based on where I was at with my system it was a logical next step. So I said...ok let's give it a try...but don't send me something that will be just slightly different/better. Also, I'm ready to take the leap but I'm not ready to leap $20k into it...so something that fits well within my system/budget and also gives me a real taste of what a streamer can do.
After a long discussion where I told him yes, I'm willing to give up ROON, and yes, I'm not intimidated by having to learn a new app....we had it narrowed down to either the N10 or the N200. I chose the N200...primarily I guess because it had very strong reviews and was the latest/greatest from Aurender at that price point.
Which brings me back to your post. The improvement I heard was not subtle. After listening to the N200 in my system for a couple days the question I had in my mind was not 'should I send it back because it's not worth the money'. The question I had...and to some extent still have...is whether I should have bought the N20. Wow. I thought my soundstage was very good before...with the N200 it exploded. I thought I was hearing detail that was reserved for only the highest resolution systems...with the N200 it's like taking my first step into hifi all over again. Every single song sounds fresh and different. New details...nuances...dynamics. Just wow. The honeymoon is back on.
I still don't understand the math...but I trust my ears. I also had a buddy come over who tends to lean further towards 'bits are bits' and he was shocked. He said he could hear the difference immediately and that it sounded less like I'd done a tweek to my existing system and more like I'd changed systems.
What we discussed afterwards was 'how is it possible that audiophiles are still split on whether a dedicated streamer provides better performance than a re-purposed computer?' I mean it's so obvious. Does it mean that the people that are arguing it doesn't matter either haven't heard one...or can't hear well...or have a bottleneck somewhere in their systems that mask the improvement? Possibly in some cases...but also I suspect that like everything else in this hobby there are so many moving parts that even though I got a great result it's not guaranteed everyone will see the same..or appreciate it in the same way.
In any case I wanted to share my experience and perhaps encourage others that are considering moving to a dedicated streamer. YMMV but IMHO it was one of the best upgrades I've ever done.