So, when my friends and I all gathered together to play the beta last Summer, we noticed this amazing echo-like enhancement whenever our fire team entered a tunnel, cave, or hallway. We all thought this was such a great little addition to modern gaming that many companies have seem to look over. We had even noticed in the Refinery that there was a sign on the wall that had a player wearing a headset, almost telling us that we should wear our headsets to experience the sound quality in all its glory. Once the game released my friends and I were all saddened to find that we no longer had that sweet environmental echoing. I wasn't sure if this was intentional or just a bug that Bungie wasn't aware of. Please look into this. It was such an amazing feature.