The general consensus seems to be that the Sundara Closed is found wanting.
As Custom Cans has done some measurements and reviews comparisons, how do people feel about the foam mod they introduced to help with this on their YouTube?
Can anyone who performed the mod shed some of their thoughts?
Very different headphones; HD 559 are open-backed. You’re going to get different sounds, and it’s all preference. You will also see people prefer one or the other.