It's stops after one hour playing & starts 2 hours later

I am a DJ so I know speakers. It sounds like you are pushing it too hard and its protection feature kicks in to prevent you from blowing the circuit or the amp in the speaker. When you are playing music next time, see if the red clipping light is staying on constantly. If it pulses every once in a while it is okay, but if its staying on then you are pushing the speaker too hard and it is killing it.

Try getting a second speaker to lesson the load on one and not have to push it as hard, if that is your issue.