Has anyone noticed this? I can hear it on the last bit of "Royals" by Lorde. It manifests as a rattle. Besides the warped sound, I fear it may damage the subwoofer long term. However, I know little of such things.
New speakers need to be "broken-in" before being able to respond to all frequencies accurately, this is done by playing a "pink noise" track repeatedly at around 50-75% volume preferably when you are not in the car