Eventually you will need to upgrade the source. This is were some of the harshness is coming from. A BVaudio SR 10 sound refiner will help. These do work and keep the op amps in the cd player from being over worked. The speakers are also part of the harshness as well. Not sure of your musical taste.But if you really want to hear your gear go with a crossover less speaker. You will be surprised at what resistors ,caps ..etc can do to the music!!
Good Luck!
Good Luck!