Disturbed song making a reference to the noise and impact resulting from dropping plates of weight from a barbell, comparing their music and attitude to the heavy drop of plates, much like a rap group might say "this how we do, son."
"Disturbed in the house, we're droppin' plates
"'Cause when you hear this shit, you'll get to steppin'
Gonna fight the war, and use my music as a weapon!"
"Droppin' Plates" refers to records, when used by the recording industry. Droppin' a plate means either throwing a record down on a turntable or taunting with gold records. "Dub plates" are commonly used by DJ's as a one-off copy for their own use. Though mostly used in Reggae, Hip-Hop or Dance Hall music, they're used in virtually any genre.
In summary, it means throwing down records.
"Wew Here we go again, get up
A little somethin' for your earhole, get up
baring a part of my soul again, get up
Disturbed in the house, were droppin' plates"
"Gonna fight the war
And use my music as a weapon"
-Disturbed - Droppin' Plates.
To come down on someone heavily in the metaphorical sense(verbally,emotionally etc.).
Well here I come, I'm droppin' plates on your a** Disturbed - Droppin' Plates