In reply to:
Please allow me to assert that speaker drivers are motors by virtue of the fact that they convert electricity into motion. Therefore, they generate heat from friction and will wear.
I will allow you to make that assertion. Will you now allow me to counter it?
(BTW, I've only got 5¢, but you can keep the change.
)
Speaker drivers are motors, yes, but the heat produced by their motion comes not from friction (except for miniscule amounts), but from the current flowing through the voice coils. No part of a speaker driver experiences contact friction (i.e. two surfaces sliding against each other). What little friction there is comes from the relative motion of microscopic molecule chains as the cone, surround, and spider flexes.
Try this experiment (only in your head if you want to). Take an average sheet of printer paper. It's pretty flimsy, right? Now grab it lengthwise, keeping it relatively taut. Now flap the sheet of paper up and down rapidly, being careful not to tear it How long do you think it will take until the paper begins to exhibit signs of wear?
