GMA Callisto VS. Merlin TSM

"Such good sound in such modest settings - to me, it felt that the speaker had removed the speaker-room equation"
It has been minimized via physics. One of the great things about GMA speakers is that they sound good with most any amplifier. I agree with Bombaywalla, at least LISTEN to the Callisto in your room. It will take a few days to get used to the time/phase coherence of the product (after all, you've spent a lifetime hearing non time/phase aligned speakers) but once you do, you'll likely never go back to high order speakers again. I never dreamed that the crossover was screwing up so much in speakers I had previously owned and listened to. Minbean you should read the design concepts pages on the GMA website. VERY informative even if your NOT buying GMA speakers, you'll learn plenty about design. Might help you in your future purchases. Good luck.

"REMARKS : It is extremely transparent/sensitive and very picky for recording. I am going to try different phono stages and cables to make it more forgiving for some situations I have to play lower-fi recordings"
Minbeam, those words you wrote struck a nerve. The ability to play and enjoy ANY recording is one of the primary advantages of time/phase aligned speakers. I no longer have un-listenable or un-enjoyable recordings in my collection since purchasing the GMA speakers.

The ability to play and enjoy ANY recording is one of the primary advantages of time/phase aligned speakers. I no longer have un-listenable or un-enjoyable recordings in my collection since purchasing the GMA speakers.

Exactly.

"The ability to play and enjoy ANY recording"
Some of my speakers have that talent and I somewhat enjoy their ability like that however I indeed need speakers to "show as is". As a developer and maker of amplifiers, I have longed speakers like TSM that can tell every difference and change of elements without veiling.
I do not have to enjoy every recording only because it is music and music shoul be enjoyable any how. I do critically enjoy recordings with real musicianship and engineering excellence.
Please don't get me wrong. "FORGIVING" way of an operation may be needed when faults of recording have to be masked and not to trigger my critical senses while I choose to be in a nostalgia or I am with guests wanting some particulr music off my standards.
Most of my favorite recordings are the ones with both real musicianship and engineering excellence, and therefore I am really benefitted by TSM-MM to show every genuine quality of the art and engineering. The more I dig out those recordings the more I learn and enjoy - TSM-MM enables me that! I would not swap my top 10 favorite records for 10000 ordinary records!
I believe that GMA's are also excellent speakers and will do try them sometime but it will not be from the belief that they can make every music enjoyable.

Many of recordings were optimized/compromised for the era's popular player like console stereo, lo-fi home stereo, boom box or even headphone stereo, and for the era's popular listeners' preferences. Those recordings have "faults" to be played by a true hi-fi system and, when played by a true hi-fi set up, often shows problems prohibiting listeners from enjoyable listening.