I have the Gen. Leather Beyer pads on 3 different pairs of Beyers and find the statement that you find them uncomfortable on that other brand RP21 to be inexplicable according to my experience with them. Perhaps there is something about the RP21 that precludes them from being comfortable with any earpad. I haven't tried those headphones, so can only pose that supposition as a reasonable explanation.
.........anyhow, I can suggest the following from having many years of leatherwork experience. First step (as many others have mentioned) is to simply mash them together while on the headphones. If you want to do more If you feel the need to go further - do the same thing, but to help things along.....simply dampen (damp, not wet) the surface before mashing them together. Remember, these are a very supple, glove-weight leather that can be ruined with overly aggressive treatment. A preparation that can be recommended instead of water and would be good for a semi-annual application would be "Leather New" - this is a liquid saddle soap that dries to a mild sheen. There is no waxy build up with this product, and little chance of overdoing it as could happen with some products (remember you are dealing with a light supple leather).
......or.........maybe you shouldn't do anything with them and simply put the orig. earpads back onto the RP21, and sell the Beyer earpads to one of the many people who seek to use them instead of their velours.
