I cant believe people are moaning about people moaning about the collar. The point is we did not like this change to the style of the game. Its not that i wasn't able to complete the dlc it just was not fun because its the opposite of what i like about the game. Its way to restrictive and canned for my tastes.
It's a simple puzzle, just stop and look around. I had no problem and it shouldn't even be close to a problem until you get inside the casino seeing as all speakers outside of it are destructible and easy to find. There are markings on the wall with words like "boom" and an arrow pointing directly to the speaker. Once inside the casino, it just becomes a simple game of: hear collar go off, step back, run in and look around for speaker, go back, make a plan to avoid it (minus the ???), profit!