404le is smooth and warm, they have very thick and weighty bass (than other stax, comparatively), resemble dynamic/planer, they almost sound as dark as lcd2 but far exceed it in every technical category. I still prefer L300LE with mod and tube re-amp and loki (so out of box 404le is a better headphone). l404le sound better for EDM and similarly tuned music.
Thank you very much for detailed answer, actually I am using an analog eq (loki, low shelf) with a tube pre amp to thicken the bass, I think I am hitting the limitation of the driver extension mentioned at 2. Ye I think I am looking for more dynamic bass. I agree with you in regard to planer exceptional bass. When I auditioned meze empyrean, it literately moved air, with multiple layers and layers of bass that overlap, feel like been hit by ocean waves from many directions(like literally), each bass note was still distinct from each other.