in case anyone is interested :)
a reply from westone's rep
Thanks for your email. The UM Pro 50 is the universal option for the ES50. They will be the same 5 driver design, just a different configuration for a universal application. The W50 is designed to reproduce frequencies of pre recorded music, not live sound like the ES50/UM Pro 50. Please let us know if you have any further questions. Thanks!
interesting but cryptic. what do they mean by not designed to reproduce live sound? my experiences gong to concert is bad booming bass, sometimes harsh highs. are they saying the UM pro 50 takes all of that away?