You could have chased her down and said, "Hi, I'm Aaron. I'm really sorry about the sound system. They said they'd have it fixed and I did all I could to make it sound ok. I just wanted to apologize in case it caused you any problems. You gave a great presentation out there." Then she would be like, "Oh, I didn't even know there was a problem. You must have done a great job! My name is ______, I was just about to get some lunch, would you like to join me?"
Then after some conversation she asks what the problem was with the sound system and then you confess that there was no problem, that you just wanted to meet her.