so i bought my sennheiser hd598se's about two years ago and i LOVE them. i use it for gaming, i listen to music on them, and more. however, im kind of wondering what else sennheiser has to offer that I would like. please note im cheap, I don't have an amp or a dac, and I listen to music from apple music on my phone. should I even upgrade? I don't consider myself an audiophile but I do like good quality music.