While I don’t have the OPN S (I only have the original OPN), I believe the OpenSound Booster is equivalent to turning the Directionality Setting in the OpenSound Navigator from the normal “Open Automatic” value to the “Full Directional” value. This favors the sound in the front over the sounds on the side and behind you. It probably also set the Noise Reduction values to max and the Transition Help to High as well. But the biggest difference is the Directionality Setting to “Full Directional”.
Many owners of the OPN S reported that they found very little difference when they chose the OpenSound Booster. Well, while I don’t have the OpenSound Booster because I don’t have the OPNN S, when I switch my OpenSound Navigator Directionality Setting to “Full Directional”, I found very little difference myself. The focus in the front is still there, but the abatement of sounds on the sides and behind me is not very strong, hence little difference.
I would attribute your hearing better in a event tonight more to having maximized on the Noise Reduction value than due to the Full Directional value setting. Hey, but every little bit helps. I would also attribute your hearing better tonight in that complex environment to your brain hearing being more and more adapted to the “open” paradigm and being less overwhelmed and being able to mentally focus on which speech you want to hear better and being able to tune your brain out to what you don’t want to hear. But of course you’d want the Noise Reduction to be set to max values to help give the speech in front more clarity for you. This way, despite still hearing all the sounds, you can single out and focus on the clarified speech in front better.