OK, back again after a "job shock" (still OK, but let's just say events happened to others resulting in added responsibilities for me), so after a bit of reading, reaching out in my personal audio circle, and considering the posts, I'm beginning to form some impressions and begin the rebuilding, at least
in part..
Said "job shock" put the immediate MX151 out of reach, as I had planned to pick it up if purchasing, since I can't do a 15 hour drive to TX I have that off the table for now. If I was going to purchase, it seemed the right choice for that model, as it still had a smidge of warranty and had never seen a shop as well as a known seller, I figured if I kept it from being shipped, all the better. That's off the table, but would likely do similar (in person pick-up) if I did settle on a Mac of any stripe.
Drivers and crossovers will be replaced on the Klipsch, they are getting updates long "in the can", known moves that I'm actually carrying out (and have done on other similar Klipsch).
Now, some tip toe through the various responses.
On 2 Channel bypass:
This is a "wife" thing.
We have a separate 2 channel system (tubes, tweaked, love it). When we originally began setting this up years ago, we contemplated doing this:
I love my Mac 2 channel system. But for home theater I prefer a mid-range AVR from the likes of Marantz, Denon, Yamaha, etc. for multiple reasons.
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All this said, what I have is my 2 channel system and separate AVR which both use the same 'front' speakers, with the speaker usage selected by a speaker selector run in reverse to act as an amp selector. In my case I care a lot more about sound quality with my 2 channel rig than my HT rig. I am OK with "good enough" for TV and movies. I realize others might prioritize differently.
This really comes down to system operability for her. If I start running these kind of setups, things get dicey if I'm not here. If she decides to turn on the TV or CD, it's a simple matter if all run off of one pre. Start running pass throughs and switches like this and it becomes an issue on the operations side.
I already do this (sorta "run the system") for her on the tube system, and am trying to keep the HT more user friendly.
This is what's blurring the issue, because I really need all this in one "pre". I need the 2 channel that is "good enough", all in one, which is a big driver/tail wagging dog here. I keep getting led back to Mac, Classe, Theta because they do that "clear/smooth" thing really well, which is what I really need. Only way I can do them is to do older models (and Theta's not really in the convo here at all, priciest of all of them).
As soon as I go "mid line AVR" - especially an older one, it's downhill from there, because the "pass through" stuff doesn't really fly here. I don't necessarily state though that I couldn't find satisfaction with say and Integra unit slightly outdated, just for the audio end, just to try out.
Just today on one of the McIntosh facebook groups is the tale of a gentleman that has been round and round with his MX121. He's desperate for a solution and his entire audio system is down as a result of it being in transit to and from service centers. There are hundreds upon hundreds of such stories to be found. Buying one of these units is a monetary risk. And for what? So that you can spend 4x the money to purchase a dolled up outdated Marantz AVP with a slick glass front panel to match the rest of your gear? Bad idea. A friend of mine here owns an MX136 - the HDMI switching quit one day. It spent months at a service center before being returned to him as not repairable. It's a doorstop now. He offered to give it to me. I passed. No thanks.
Sorry McIntosh. You've just absolutely missed the ball here by not making things right with these customers.
This is what I'm trying to "get to the bottom of". Just how reliable ARE these?? I'm having trouble finding the "hundreds upon hundreds" and am trying to discern just what percentage of these pieces have this occur. I don't doubt you necessarily, but yet to understand that the naysayers in any internet opinion discussion tend to control the "volume" in terms of "loud". So they are "more heard". These days, it seems harder to find just what the issues are, and how prevalent. I certainly understand/can relate to the "computer" part of this, and am not surprised that after a certain point they cannot be repaired. My Krell blew after 20ish years, but that said, I'm not sure it owes anyone much after that.......
I'm not on Facebook so I don't have that "view". Do you have any links of this stuff, or is this just more from memory?
Here's an idea. Why not a 2.1 setup? I've done the 5.1 surround thing, reduced it to 3.1, and now it's 2.1. We're not big into movies, so for my use case, I don't see the need for all the extra stuff. Plus, I'd rather have a killer set of speakers for 2 channel rather than an okay set of surround speaker.
This past December, my 12 year old Onkyo AVR finally went out. It had been used for 5.1; however, over the last 8 years it was only in a 3.1 configuration. All that said, I don't currently feel like I'm missing out with the 20 year old Yamaha AVR that's filling the role now. So, the next time I overhaul the setup, it will be 2.1 with the TV doing the HDMI switching and the TV digital output feeding into a DAC.
5.1 seems to be the "decided setup", We looked into doing just what you did, in fact when this was conceived we considered it (even the PWK "mixed mono" trick). We couldn't quite get the Klipschorns in there (we would have just had no subs, but it's moot anyway), Belle Klipsch (pricey to just buy one, then get it matched up all the same, gave up after a few years of looking for matches), then found a series of Cornwalls (three sets total under $2500 acquisition price for all) and that just sealed the deal. All good speakers (no small speaker "compromises" and thus impeccable timbre matching) In a speaker that has been soooooo right in it's basics for so many years that I can't justify getting rid of them. In fact, given that Klipsch is selling new pairs for 6K, I know full well that the work I'm about to do on these will be worth every penny.
I'm not much of a movie buff anymore, but what's really swaying the decision to stay in 5.1 NOW is "broadcast". This is becoming standard online and has been standard for years on cable/sat.