Sound is where there is one who interpret it as sound. No one, no sound!
When we look, we see what we tend to see. When we listen, we hear what we expect to hear. When we turn off our presumptions, we do not see and hear anything, anymore. Everything looks the same. This is the unity. The only thing that can make this turn-off happen, is death. Then, we look, but we do not see anything ... we listen, but we do not hear ... because ... we are unified ...