I think Feri's comments about clipping would be correct if limited to subwoofers. The higher order distortion would not be fed to the non-sub drivers, band limited so to speak, and would therefore probably do no harm. The sub could fail if fed too loud a signal, especially if its below the tuned frequency of the sub or if it overheats from a signal too loud for too long a time.
Feri seems to be saying that clipping is never a problem and can never cause any damage to ANY speakers. At least that is how I read this:
"Keith my friend, clipping of a sinusoidal signal means it's being transformed into a square wave. Feed this into a speaker and the speaker will play it. It will sound distorted, but the speaker does not care, it just plays what is fed into it. Feed a speaker with a distorted signal or a pure signal makes no difference for the speaker. You can't distroy a speaker with a clipped signal because the peak-to-peak voltage does not change. A speaker can only be destroyed by mechanical or thermal overload. A clipped signal will cause neither of these two cases."
FWIW, I believe he is entirely wrong that a clipped signal cannot cause thermal overload in the voice coil and thus destroy it. At his behest, I googled the subject and the first page of hits confirmed my viewpoint. (My bolding)