Incredible Audiophile Imaging -- at a Concert!

I was just at a music festival in the mountains near the border of Portugal and Spain. One of the shows was the duo of Maria João (vocalist -- either an acquired tasted or too weird, depending on your preferences) and Mário Laginha (an excellent pianist). The concert was outdoors in the ruins of the ancient Roman city of Ammaia. The sound system consisted of two line arrays, nothing more. But it was incredibly well mic'ed. A pic with the techs setting up is attached. We were seated very close to the sound boards.

About two songs into the concert, I realized that Laginha's piano was mic'ed so that an image of the keyboard, in incredible detail, was mapped from the left line array to the right. Closing my eyes, I could "see" this entire 70 foot wide keyboard image, to a level of detail that any musician who knows keys and scales could easily reconstruct exactly what Laginha was playing. It was absolutely amazing! I had never heard sound with that level of clarity, detail, and imaging in a concert before. The purpose-built San Francisco Jazz Center probably comes close in my experience, but a somewhat distant second place to this simple line array system.

I'm sure this effect was helped by there being no walls or ceiling to create any reflections. And I'm sure being right next to the sound engineers contributed. Did the altitude or cold temperatures matter? Regardless, it made Laginha's playing that much more enjoyable. It was such a treat compared to concerts held at stadium venues, or even large clubs, where the sound often sucks.

I read up on line arrays at https://www.soundonsound.com/techniques/line-arrays-explained to get a better appreciation.

Wondering if any other 'goners have experienced something like this at a concert. If so, what was the venue? What do you think contributed to the stellar imaging?