First, you're going to have to define what poor sound means to you. Modding your closed back headphones to add more speakers isn't going to make them sound better, but probably worse.
The best way to get better sound is to replace your headphones with better headphones, or to use a better source when playing music. Even better headphones aren't going to improve the quality of music if you're playing lossy Mp3s.
Trump's loyalty/humiliation test