Being on dial-up, a "movie of a noise" is just an impossible concept for me, but there is no "normal enclosure vibration". I do have to disassemble my SVS every 6 months or so to tighten up whatever came loose recently, but there should be no noise coming from your sub other than what is on your media. You can get port "turbulence" and noise from overdriven woofers, but EP500s are probably less prone to those artifacts than pretty much any sub on the market.
Keep at it.
Someone with a faster internet connection please listen to the noise and comment
