Speakers are not physically buzzing.
There is a sort of interference/whine/nuisance coming from my speakers. I think it has to with alternator because it only does it when the car is running and the pitch of the whine fluctuates with the rpms. The louder the volume, the louder the whine.
My set up is in my sig, have a 12" Polk Audio DXi sub with an Alpine V-power amp and other crap. I have a recording of it which ill try to post later.
Edit: here hopefully this works. theres music for the first 8 seconds and then i rev it a little. Then I talk to myself lol