I have a similar room shape as you, with large openings to one side. I’m smiling as I read you comments on your upstairs system, yup that missing mid bass you refer to is something I’ve heard often and I find takes away from a system being able to put a grin on your face. I call that HT focused sound, not that they all do that but too much boom and sizzle, not enough in the middle.
I also for the first time had enough to consider buying some great speakers for my only music/HT system, and started with the center channel. My goal was clear, full mid bass and great off center sound, so that means getting away from MTM to a proper 3 way. With a centered tweeter and midrange, woofers to the side now you can sit l/r of center and not be getting a different sound than right in the middle.
Why did I start with the center? Well I wanted a front soundstage that would be a matching LCR setup, and to be honest realizing that few centers were proper 3ways, narrowed down the options considerably. I then setup a Tidal playlist of select tracks me and the wife are familiar with to start listening.
We were lucky to hear the F208 and C208 center which is a proper 3 way design. Nice looking cabinet, but there was no life. I know from seeing the measurements and tests that it should be great, but it failed the put a smile on your face test for both of us. I even repeated a visit to try again, even with the speakers in another room and still the same result.
Then the KEF R700 and R600C, with their concentric drivers. I’ve always been interested in what kind of pinpoint imaging you could get from a concentric design, and the center should be even better as the TM is one with flanking woofers. This was another sat up that went back and forth to, but short version is that the trade offs of a recessed tweeter radiating from within a mid are noticeable and the clarity for us was just not there.
Tried a number of the Focal series, alas they don’t make proper 3 way center, but wanted to hear what the 9XX models had to offer having had listened to them in a 2.0 setup, we both liked the sound and again returned to hear them more than once, but while pleasing they again lacked the last bit, fun. When it came to looking for center to match, the CC 900 was so bad even the dealer apologized after it was played, I think the look of disappointment was pretty apparent on my face.
At that point what do we try now, so started to look at speakers at higher price brackets and oddly some were more colored, or left saying wow that’s all you get (sound wise) for 2x and 3x the money? Keeping this short(er) the only contender up there was the Monitor Audio PL300 II. They offer a matching PLC350 II center, and I’ll say that the 300’s filled the fun to listen box but there was some harshness in the upper midrange that was evident only one a couple of our test tracks, oh then there was the price, even with discounts these were getting way above where we started, but they did get closer to our goal, a technically competent speaker can exist that can also be fun to listen to.
In the back of my mind there was also Ascend, kept hearing great things about them for years, spoke with both Dina and Dave and was impressed with their passion. Nice cabinets, wide choice of finishes, well engineered drivers and the RAAL tweeters. after spending hundreds of hours listening, reading and comparing it was time to try ordering the Sierra Towers and Horizon center all either RAAL tweeters. I’m not going to give you first impressions but rather I’ll say this, I don’t read about speakers anymore
If I was stranded on a desert island or stuck at home (oh ya like now...) and only had one set of speakers to live with these tick all the boxes. Fun, toe tapping, great imaging, excellent dialogue with full midbass, even on the center.
The Horizon RAAL center is so good, I never need to turn up the sound to hear lines in movies anymore, the width of the sound from it easily covers the width of the room. And it puts out great midbass, deep make vocals sound rich without being boomy.
The Sierra RAAL Towers are great at imaging, sitting at my usual off center chair listening to music, I have had to get up on numerous occasions to confirm that the center is not playing the vocals, that’s crazy! It really is that convincing that I get up to double check I don’t have it playing accidentally via upmixing in my pre-pro, but it’s not playing at all when I put my ear to it. The midbass of these also not boomy at all, there are no gaps in the frequency range (I’m looking at you Paradigm F95), there is no harshness in the mids or highs. The RAAL tweeters really do have fast, detailed but never harsh done just right sound.
I will end that the true test is what happens when I came home late from a long day working yesterday, the wife had the stereo cranked listening to her carefully built playlists while doing dishes with a smile on her face, perfect! That says it all, she really does enjoy them as much as I do.
Summary is buy a system that makes you smile, uses well engineered parts and is put together by people passionate about enjoying music. Even after the new gear honeymoon, the Ascends have remained as satisfying as they were the day they arrived some 2 years ago. The value proposition is also there, the full LCR setup with RAAL, premium finishes (we have satin espresso and they look great) and shipping still leaves you with $1300 that would be better put to use for sound treatments vs paying for marketing departments. They are also an easy load to drive, so your Yamaha would work very well with them too.
Enjoy your journey whatever you decide!