Interesting comment, but I think your experience of "exaggerated 3D" is easily explainable since you mentioned your benchmark is a "live concert". The Bacch doesn't seek to recreate a live concert....unless that's what was intended in the recording. Most recordings are studio based and not the prototype concert or live event that you are using as a benchmark.You are talking about the audible effects of using the BACCH program to process stereo playback as heard from the listening seat. See the detailed TAS review and discussion of how BACCH works here. That device uses a pair of small microphones which you place in your ear canals to set up the system by measuring the sound impinging on your two ears at the listening position and "correcting" what the speakers sound like to compensate for a number of effects related to headshadowing and the fact that stereo imaging is not "real" but "virtual" in the sense that the brain operates on what your two ears hear to create phantom virtual images from the two separate sources (two speakers) generating the sound rather than the single "real" source we hear in nature.
The goal of BACCH is not so much to create a flat frequency response than to create a more (MUCH more) three dimensional sound field. From the demos I've heard of it so far (at the 2022 AXPONA event), the system goes far beyond what I hear at a live event in creating three-dimensionality. If normal stereo soundstaging is not three dimensional enough, BACCH sounds surreal in a laughable fun-house way. Others seem to disagree (see the linked review), but I think they are just fascinated with the rather obviously exaggerated stereo effects BACCH produces compared to what one hears in a concert hall. Interesting and fascinating perhaps, but hardly realistic. And BACCH effects are hardly new to the audio scene. Ralph Glasgal's Audiophonics, the Carver Sonic Hologram, and TacT's XTC system are all eariler attempts. Yes, BACCH removes the "phasey" tugging at your ears that prior systems tend to produce, but it also further exaggerates the stereo effect far beyond what is natural.
Having measured the frequency response of my audio systems when the Carver Sonic Holgram and the TacT XTC were employed, I know that such systems drastically alter the measured response one gets from a measuring microphone positioned between where your ears would be in the listening position, especially when measuring both channel outputs at once. The idea of such systems is not to produce flatter frequency response, but to alter the way our brain perceives the soundfield sound generated by two separate loudspeaker sources. Frequency response manipulation is part of the processing involved in that effort.
I think you will find (at least I do) that setting up the Sanders 10e speakers as I have to eliminate room reflections to a great extent, you will hear much more three-dimensional stereo than with most other speakers. You can improve the stereo effect with all speakers using acoustical room treatment, but you get further with the Sanders since, other than the back wave, it is so very directional in the first place. What I hear in terms of soundstaging is quite natural sounding to me, much moreso than what I've heard from any of these systems, including BACCH. That's my current opinion, obviously, subject to alteration on further experience with BACCH at the coming AXPONA.
The Bacch is giving you a more accurate representation of the spatial cues based on the mics to the instruments. If the mic is hung from the ceiling and a standing bass is being played below it, you likely won't think the location you hear of the bass represents a "live event" presentation...but it's more ACCURATE...Elvis Presley "Fever" is a perfect example of that with the Bacch...we have pics of the recording studio to confirm the orientation of instruments and mics.
There's no technology YET that will place you in the soundfield wherever YOU want, but as I showed in a recent video...it's coming. However, it will require HRTF measurements and certain recording mics.... which gets back to your experience. What specific recording(s) did you listen to where the soundfield is "exaggerated"?
One thing that the Bacch will expose is poor spacing in cardioid mic placement, such that it's possible you'll find some recording flaws more evident... although it's rare. It shouldn't exaggerate anything and, if fact, few people get high enough XTC to make it perfect, so "exaggeration" is a term that would only apply if you have a flawed benchmark and don't want a more accurate representation of what was recorded.
How do I know with 100% certainty that the Bacch isn't exaggerating 3D (assuming you took measurements correctly and your room is treated to let you hear your speakers and not the room)? All you have to do is bring up a YouTube video of a binaural recording. You can literally watch how it was recorded as it is being played back. You can't get any greater proof than that...or can you?
You can go one step further. You can use the mics on the Bacch to make recordings yourself. Record yourself snapping your fingers around your head at various distances and then play it back on your system with the Bacch filter. You'll see that it's far more accurate than without the Bacch, but if anything it's still falls short of 100% 3D, so your claim of "exaggeration" will be tempered by reality if you try these things. As good as the Bacch is, almost nobody would say it gets the recording 100% equal to the spatial aspects of snapping your fingers live near your head. It again will be FAR better than without using Bacch, but nobody would claim it's exaggerated after doing that test.
Nevertheless, even if you STILL believe that the 3D effect is exaggerated, there's another solution built into the program. There is a slider where you can dial back the crosstalk cancellation from 100% to whatever percentage you feel meets your benchmark of a live event. You can literally do this on each song to your taste...this gives you a slam dunk advantage over any system WITHOUT Bacch. Plus, you can also bypass the effect totally on certain recordings if you want.
If anything, the 3D effect will only get greater over time as more binaural recordings become standard and people pivot to better speakers and rooms. Thus, it's important to understand that it's only revealing spatial ques in the recording itself. If you think it's too exaggerated and you don't like a fly buzzing around your ear like with Grantchester Meadows, I would take it up with the recording artist that mastered it different from YOUR preferred benchmark of a live event. It's now much closer to where the recording intended with Bacch, and the experiments I outlined should prove that unequivocally to you if you get a chance.
BTW, Edgar uses the Sanders in his home, so the variable of "type of speaker" is also taken out of the equation. That's a nice speaker you own and I can see why you like it without Bacch, but you may need to revisit your exposure and accurately calibrate your benchmarks to realize what you are hearing isn't artificially exaggerated unless that's what the recording reveals.