Speakers lose volume over time......

Anyone noticed this?

I have a set of Logitech Z-5500 digital speakers (505W RMS 5.1 surround and a huge 10" sub)
http://www.logitech.com/index.cfm/sp...s/224&cl=gb,en

Anyway, in my opinion the volume these kick out has deteriorated over time. Does anyone else notice this with their systems? And why does it do it?

i have the same speakers, and haven't noticed this

i think you're just used to them, or your subwoofer is on it's way out