I have been through this and have the exact same issue as the poster with upper mids and highs. If you measured it, you would find the upper mids are also a problem.
Wire will change things a little, and new CD player or dac may change or improve things a little. Do yourself a huge favor and call Steve at Empirical Audio. He has the solution to your issue that is pure sonic heaven for those of us with upper mids and highs sensitivity. I can't go to most live concerts anymore unless the venue has great sound.
I use his Offramp and Bnc cable on my dac/computer combo and they took my digital to a completely different level. I so enjoy all my music again. The problem is most likely jitter and the noise and glare associated with it.
You must try his product and see for yourself. They are not cheap, but they will transform your digital front end.