We have combined cycles and Rankine cycles with reheat, so there is ongoing innovation in the energy conversion field. Heat engines are also just limited to the Carnot efficiency. We hit finishing returns quite quickly.

Fuel cells, however can achieve higher efficiencies, but operate on a different principle.

Better decide quick because the discount is about to expire in a couple days. $80 is the regular price.

Paul measured them with the included foam tips, which should tame the upper treble a bit.

Paul Wasabii's first impressions are that it's competitive with the other planars, despite only being $40. Smokes everything in the $40 range in technicalities.

Here's another set of first impressions: https://youtu.be/6YAY2Am_LI8

I think they are referring to flathead earphones, which are called "earbuds" in enthusiast communities.

I'm assuming you're using "earbuds" to refer to any earphone? I would change the wording to "earphone" to remove confusion.

I highly doubt the EDX are neutral. Definitely less so than the Aria, at least.