Power cord to add ease and tame treble.

Did you try the Cardas Golden Reference speaker cable? I ask because in my experiences the Cardas seems to be quite smooth. The Ridge Street, although quit revealing, was a bit thin, leading towards listener fatigue, IMHO. I should mention that my Ridge Street experiences were with the interconnects, I haven't tried the speaker cables.

As far as a power cord to smooth the treble, try a Shunyata Cobra/Viper/Python, at least on your Ayre cd player. If you're looking to spend less, try a Cardas Golden Reference power cord.

TG Audio 688 on the CDP plus some good isolation under it.

Try harmonix studio master.

If you really think about power cord, I suggest you just get the shielded version like the CVH DIY cable for digital source.

Sounds more like an AC issue. What do you have the system plugged into and how is the AC delivered to you system? I will be experimenting with some AC noise products that come off my fuse box prior to the AC coming to my dedicated AC lines and Porter outlets. At my friends home, fixing the AC took away the harshness in his system. Don't buy a power cord until you have fix the AC. There have been several posts about this subject and excellent comments from Sean, Psychicanimal and Lak. Look up their posts on this subject. I was chasing the same issues you were but this makes more sense before you spend money in another direction.

Happy Listening.