Right so I just tested my Elear with this song and compared it to 4 other headphones I currently have with me: HD800S, K7XX, Atticus and LCD-3.
There is indeed something going on design-wise when it comes to sub bass handling by there Elear (and therefore Elex) drivers. When the sub hits at around 3:26, at normal to loud volume, I'm not hearing anything but smooth sub on the Elear. However turn it up a few notches and I start hearing faint pops and a crackle or two. I then tried the same thing with the other headphones. Each handled it slightly different ly in terms of the "smoothness" of the sub bass, with the Atticus/LCD-3 being by far the best, followed by the HD800 and K7XX, but not one "clipped" or crackled or popped, even when the volume dial was way past the 12PM mark which, if the rest of the song were to come on at that point, would render me deaf.
So yes, the Elear, in this case, is designed to audibly let you know when it's clipping in the sub bass region, but consider this: The Elear is easily the most sensitive of my headphones. It's also the most dynamic. At 9 o'clock and high gain on my R2R-11 this song is just about as loud as I'd care to listen to it. All the others have to be turned up past 10 for the same level. The "clipping" on the Elear starts around 10.30, which would be about 11.30/12 on the other headphones, and again, painful volume. So practically speaking, I should never hit the clipping point, especially since most songs don't make such prodigious use of sub bass. Also, FWIW, the Elear renders this track better than any of my other headphones, matched only by the LCD-3, which costs twice as much.
I've also had a listen to the "Whiskey" track (not my cup of tea, excuse the pun), but the "clipping" starts at volumes well beyond those I'd care to listen to this song at, and at the same levels, even though headphones like the HD800S don't clip, they're so sibilant I'd rather have the clipping.
Now, I know all of the above was done on an Elear and not an Elex. Whether or not the design tolerances are different for the Elex than the Elear, I'm not sure. You'd have to ask Focal. Which is why it would be interesting to put Elex pads on an Elear and see if it clips more easily, possibly because you're turning it up louder than you would the more dynamic and punchy Elear to get the same effect.