Answer:
The music was played at an natural frequency of the drums
Explanation:
The natural frequency of a body is the frequency when we notice that the system oscillates without any driving or damping force. This is also referred to as the normal mode of vibration because all parts of the system move sinusoidally at the same frequency.
So, when music is played at the natural frequency of the drums, the drums tends to vibrate without any driving force. We can now say that the drums are 'playing themselves'.
