Yes! Undergraduate work is about basic skills + learning skills + finding your interests. Just do some research into some graduate programs in acoustics, and find out what the undergraduate requirements are. I believe you probably have covered them if you've majored in music + math/physics, but you will want to make sure, in case there is an additional one or two classes you should take. It's GREAT to have an interest and follow it... your drive toward specific goals will be a great motivation. Good luck!