It's great that you are meditating and starting to have some clairsentient experiences! Meditation works differently for everyone. It's OK to listen to calm music, or even buy a CD or DVD of guided meditations where someone talks and takes you on a journey, and you listen to that. Om chants are good, when you either chant or repeat a mantra in your mind, it's purpose is to block you from thinking of everyday things and let your mind wander to see if there are any messages out there from the Universe, or people that may have passed. I like to smell a scented candle, and often see colors in my meditations. I like it to be quiet, and repeat the mantra in my head. But quiet music or anything gentle which helps or soothes you are fine. Best wishes and I hope you continue! It's exciting that your abilities are increasing.
You can also burn sage to get rid of negative energies around you before you meditate, or hold a crystal that has qualities you need.