I sometimes noticed a definate "tinnitus effect" when listening to my system. Aside from the fact that I am getting older, I believe this ocassional experience of high frequency ringing may manifest from the superior playback ability of high-end equipment, thus perhaps revealing mastering errors. For example, I have the new B&W 802D's that, with the diamond tweeters, register way beyond "normal" human hearing in the high frequency range... and I have an excellent Wadia CD player also. I especially notice this with certain jazz piano music, especially when accompanied by delicate brushed cymbals, i.e.,in jazz trios. It almost sounds like a cell phone is quietly ringing in another room. This phemomena does not happen on all my CD's but only on some which leads me to my above opinion concerning mastering issues.