Have you visited an audiologist? This is a must for any one into the high end. A full 'spectrum' hearing test is a must, not the standard test that generally stops at 8K. With a test you will know what your hearing curve is all about and can 'see' where your hearing may be adding bias to your listening choices. Use the visit to get a good pair of ear molds made for listening with your portable player.
Lastly, have you had a doctor check your ear wax? Yes, it will make a difference in what you hear. I have a doctor check twice a year and it make a big difference.
Lastly, have you had a doctor check your ear wax? Yes, it will make a difference in what you hear. I have a doctor check twice a year and it make a big difference.