"I like the sound of that" is a positive response to seeing something in a new way. If someone give you a new perspective, just say - I like the sound of that. It means, that rings true, or - that's how I want to see things... It doesn't usually get said if it is not a positive situation. Once in a while you might hear it if someone is being offered a bad deal. "I'll give you a punch in the gut if you pay a dollar." "I don't like the sound of that." Someone may say - I don't like the sound of that would be with music they hear and do not like. (of course)

In the same situation you might also say "that doesn't look too good" or "that doesn't feel right to me". Perhaps your friend suggests you do something dangerous. You do not think it will have a very happy outcome if you go ahead with the plan. You would say, "I don't like the sound of that".

When you don't like anything you hear.