I don't think you should pretend to like something you detest. It seems that after you told them you didn't like the music the groove of the conversation stopped. Usually when I find that I hit a wall conversation wise I smile and jump into story mode. You could of told them a story of how you enjoy talking to people who have different music tastes than you , and talk about a friend of yours who listens to other music and it's interesting to hear his point of view on things. Or you could of talked about how people have different tastes concerning food and how some things that look weird might taste good. So the underlying message is that you like to talk to different people and explore life. 

 Sometimes your story can be completely unrelated or have just a tinny connection to the previous topic of conversation. Most girls enjoy when guys tell stories because it takes the pressure off of them and they get to be entertained. As you are telling a story make sure you get all of their attention by projecting your voice and making eye contact or slightly touching the ones who start getting distracted. If there is a point in your story where you describe your feelings you can pause and say "you know" or "you ever felt like that" or anything similar while you nod, and they instinctively agree with you.

The only problem with preppy dingy girls is that they might think you are too smart or too intellectual for them. A way to prevent this is through self-deprecation. You don't want to be seen as a know it all so mention sometimes that you wish you knew more about something or lack understanding of a certain area. 

Next time you find yourself in a situation where conversation is dying down just jump into a story and hopefully the groove will pick up and you can isolate and escalate.