So here's how to kill that grating 2khz peak in your ear.
I deduced (induced) that it was caused be the middle dome of the driver breaking up, and the rest of the higher treble was made by various breakup modes in the 'cone' part. I put a "7/16 (11mm) diameter piece of tape over the center hole (my sr-60i have the cloth still) in hopes of getting some phasing action to cancel the frequency somewhat.
I experimented with different tapes. Don't use any tape (duct, gaffer, masking) with white adhesive, it will eventually turn to white powder or cement. Use tapes with clear adhesive. I found regular matte 'invisible' office tape to be a good proof of concept if you want to try it, but a little bright, still. Good 3M vinyl electrical tape was a bit too dull, with weird highs. The best, which sounds great is 'Scotch Decorate and Repair tape', which of course is no longer made. It's just cheap vinyl tape though, very thin, like you'd find at the dollar store.
edit: Sticking the tape on the inside of the pad works just as well, but put your various test tapes over the hole first, because you'll be pulling them off, and putting them back on, and pulling them off again. The foam might deteriorate.
edit2: actually, that works better.
I have SR-60i's with s cush.
I hope this helps you love your Grado's, I love mine.
Edited by tansand - 7/17/16 at 9:13am