Original Message

Slight misunderstanding, i completely agree that the first doorbell camera you hear a massive over speed that goes away as large amount of pitch is pulled in at the bottom and rpm returns to 100 percent as he flies overhead. Both engines operating at full power  

I was referring to the second camera that caught the impact. You can hear as blade contact I'm guessing a tree while aircraft is out of frame the rpm is decaying. Then as it appears in frame and other blade impacts begin it is decaying further and based on how hard it hit despite the flare and I'm sure an armful of collective I think the rpm was low at the bottom. When it rolls over you can hear the engines or at least one engine running but certainly is screaming along. Granted this from a junky doorb camera microphone. 

sorry for not clearly referring to the two different videos.