Summarry...:
This is only one sound I tried to play... I don't know if I have the syntax wrong, but I went directly to the legacy.json to try and find the right directory...

What I expected to happen was...:
the proper sound would play
What actually happened was...:
no sound played at all

Steps to Reproduce:
1. Type in "/playsound ambient.cave.cave @p"
2. Tell me if I'm going crazy...

Note:
The version number isn't available to choose.
It actually is 1.6.1+