Looking to get my first set of headphones. Any suggestions? Like to keep it under $500 since I don’t really know if it will be my thing. I was thinking of a used pair of Koss esp9’s.
Yes, sound quality will be negatively impacted by using Bluetooth. If you need the wireless functionality, then it's certainly the way to go. If the cord isn't a big deal, then you're better off keeping it.
I have Sennheiser RS185 wireless headphones for tv/movies and for music during my too rare workouts. They sound surprisingly good for wireless. To my ears, their sound signature is very much like the HD6XX.