Having had experience of noisy neighbours a few times, if I were you, I'd first go and say hello and introduce yourself as the new person downstairs. Then having hopefully made an amicable intro you can mention how badly the sound travels through the floor and ask if they could turn the volume down, invite them down to hear it for themselves if necessary. Try to do this when you are not in the middle of being wound up by the noise so you're in as neutral a frame of mind as possible. If the friendly request is then ignored, you'll at least know where you stand and it's time to keep the noise record and pursue through more official channels.