Audiosense T800
I've never heard music with such transparency and detail. It is as if you can "see" very clearly everything that is happening in the music.
And one thing that impressed me was also the weight of the instruments. I could feel the husky rustle of the saxophone, the weight of a graver note on the piano, the drumbeat's physicality.
Unfortunately I have basically the KZ as10, zs10, zs7, zs6, as parameter for in ear comparison. But I have some over ear references like the hd600, he560, hd58x, AKG N90q, Superlux hd681, Pro Port ...
I know it's not ideal to compare an ear with over ear, but in relation to those over ears I mentioned, it's the first time I hear so many details and textures.
This was what most struck me initially.