Burn in Capacitor phenomena

Hello,

I just wanted to post about something I've just experienced with burning capacitors and a theory on a contributing reason to why they may sound different with time on them.

I made a capacitor burn in rig that play's music through the capacitors for burn in. During startup of this rig I noticed as the electric pulses of music pass through the capacitors they vibrate. That is you can hear the capacitors playing music. Over time I've noticed the volume or vibrational amplitude seems to have gotten slightly smaller. I am just throwing this out there, but my hypothesis is; that as electricity passes through, there is heating and swelling of the parts, the parts then undergo greater pressures and a greater sense of malleability and stickyness for a lack of a better word. These parts begin to Stick together and oils or plastics begin to settle into imperfections in the surface of the foils, ie: the parts meld causing a less ressonant (or perhaps a coupled resonance allowing the capacitor to resonate as a whole) sum of parts.

Why else would the capacitor become percievably less quieter? Other than a drop in frequency or less resonant.
perhaps because it's burning out, haha, I hope not.

Anyway I notice a difference in capacitor sound quality with time, and typically it sounds better as a less resonant capacitor probably would.

Thoughts?