If it is heard by others it doesn't matter in that case, your intent was to play them for yourself. If you went out though into a park and gathered a lot of people together to do say a dance off or whatever else, then technically it isn't for your own enjoyment anymore it is playing for the public and you would be in infringement. Here is an example though where you wouldn't be in infringement and could monetize though. Say you were making a video of someone in your house of them dancing. And in the background they had music playing, then you aren't in violation because the music was captured incidental to what your intent was. Same thing if you went to a public (free) concert and you were doing a video of your friends acting the fool and you captured the music in the background, it isn't an infringement. Music copyright law is really not cut and dry as you might think it is. I have learned about the nuances over many years of working with a non profit and doing video for them. I still don't know everything there is to know about it, but I do know more than the average person because I have been directly involved with some productions.