By way of introduction, I'm the guy who sent Dave the email (about my recently completed 1801F's) referencing Jack Nicholson's line, "You can't handle the truth!" from the movie A Few Good Men.
I'd like to share a slightly different point of view. It's more philosophical than technical, so stop reading now if you can't tolerate that sort of thing. It's also really long...
Dave, you didn't state outright that high resolution equates to high quality, but that seems to be the implication. If I'm wrong about that, much of what I'm about to say is probably off the mark.
If I follow you, you seem to make three points. (1) High-quality recordings of symphony orchestras require a high-resolution (high-quality) speaker. (2) Pop recordings (presumably, even high-quality ones) don't really require a quality speaker. (3) Further, you can't enjoy mediocre-quality pop recordings, or 70's rock, on a high-quality speaker like the 1801.
It's hard to argue your first point. There is a lot going on (lots of detail) on when an orchestra plays, and it does take a quality stereo system to reproduce all of it. Interestingly, though, the thing I notice when I hear an orchestra or jazz band play live is not the amount of detail present, but the amazing dynamics, and the wall of sound produced. Orchestras/bands can go from very quiet to very loud in a heartbeat, very effortlessly. They go from a "whisper to a scream" as opposed to a typical rock band's "bellow to a roar."
I start to part company with you on the second point. There's a huge spectrum of music between a full-blown orchestra and a small pop group. I contend that any well-recorded music, complex or simple, high detail or low, is worthy of high-quality reproduction. For example, I think Mary Black's or Loreena McKennitt's voice, or Patty Larkin's guitar is just as worthy as Yo-Yo Ma's cello or the London Symphony Orchestra. Sure, there's not as much detail in one of these artists' pop/folk recordings, but there's plenty of "micro" detail, if that makes any sense. The same is true of a solo piano or chamber music recording. The ensemble is small--is there enough detail there to warrant a high-quality speaker? (I don't listen to chamber music, but I think the answer is yes.)
To use a visual analogy, the photographer at the portrait studio doesn't stow his good camera and pull out an old Kodak Instamatic to take a single model's photo because there's too little detail to capture in just one person to warrant the use of the good camera. (I realize this analogy is poor because the model, being a real live person, has almost infinite detail. But, still, one model presents less detail to capture than a group shot.)
But it's really the third point of view that I find difficult to understand. I've read similar comments from other owners of 1801s and other highly-regarded speakers. Comments like, "My new system is so great that most of my recordings sound like junk!" always make me cringe a bit. I think the system is there to serve the music (the majority of it, and not just the best-recorded, top 1% material), not vice-versa, and that no audio component should cause one to stop listening to recordings they like.
Here's where I'll use another visual analogy (hopefully a better one). Suppose you have two photos. Let's make them 8x10's, which means they can potentially show a lot of detail. One of them is a perfect photo (of what, it doesn't particularly matter). The other is sort of grainy, slightly out-of-focus, and it's of something you treasure deeply (your first car, your wife, your favorite childhood toy, your speakers

, etc.) You can enjoy both photos, even though the second is of mediocre (or worse) quality.
Now let's say you want to scan those photos to preserve a copy, or to post on a web site, or to send to your sister. You go out and buy the highest-quality scanner and imaging software you can afford. You scan both photos. The scan of the perfect photo still looks great, and of course you can still enjoy it. The other scan looks like the photo. It's still grainy, and it easily exposes all the original's flaws. But it doesn't highlight them unduly, either. You knew those flaws were always there, and you can still enjoy looking at the scanned image. It still means something to you. You don't cover your eyes and run screaming from the room. You don't banish that image to your old computer with the crummy monitor.
To return to music, if a new audio component makes me avoid my good-but-not-great recordings, maybe it's telling me the truth, but not the whole truth. Maybe it's emphasizing the bad things while neglecting the good things. I think most of us have known someone like that, someone who always "tells it like it is" and criticizes everyone and everything within sight. Technically, they may be right, but they're generally not the kind of people you want to hang around with.
To be clear, I'm not saying or implying that my 1801F's are the musical equivalent of that type of person. To my ears, they sound really good (with many types of music) at low levels, but too forward at louder levels. That characteristic may be inherent to the speakers, or it may be the result of my Creek integrated amp running out of steam, contruction errors, unoptimized port length, poor room acoustics, or something else.
I think maybe I just don't like the sound of an truly flat speaker (or even one that's 2 dB down on the top end--I used the 8/12.5 resistor option). Maybe I don't crave detail as much as many audiophiles. I want to hear the details, but I don't need them thrust in my face.
I do think I am going to be happy with my 1801F's in the long term, but I think I may have to do something to pad the treble down even more. I think that will balance the sound on most of my recordings, while preserving the clarity I hear from the midrange down. Granted, the sound may not be as accurate, and maybe I'll have to turn in my audiophile credentials, but that's OK. I'd rather optimize my system for the typical case, rather than for the best case. That's the beauty of DIY, isn't it?
I think a speaker can be great (and be considered high-resolution) without being ruthlessly revealing. Such a speaker can sound great with great recordings of all types of music (not just large-scale classical music), good with good recordings, and bad with bad recordings. But it doesn't have to be something that sounds great with 5% of my collection, and terrible with the other 95%. I'm hopeful that, with more tweaking, my 1801F's can be such a speaker (for me, in my room, with my equipment). So, I guess I'd reply to Jack, "Yes, I can handle the truth. Just back up a little, and stop shouting at me."
Ron