"Sound" is a form of energy. It exists whether or not someone can hear it. It doesn't require someone to be in the forest for the energy to be created, it's created regardless. If a deaf person was standing in the forest and the tree fell behind them but they couldn't hear it, would it still make a sound? Sort of. It would still give out energy that was in the form of sound waves which may or may not be heard by the human ear. But whether or not those sound waves are heard is irrelevant, they exist by virtue of the transmission of kinetic energy.

As for Locke. I'll put my hand up and admit I don't know much about his work. The reference you gave me was on Civil Government. I'm going to guess that Locke was arguing for what we might call representative democracy where a monarch isn't the sole arbiter of what we can and can't do, where we decide what we can and can't do.

I'll need a bit of help in working out Locke's idea of rights though. I do maintain that what we call "rights" are simply human customs and therefore invented by humans.