can you elaborate? I've always thought the er4s was more silky smooth, yet they graph identically to the er4sr. is it the impedance and other technicalities?
Yes, ER4S sounds ever smoother to my ears as well, with better sense of air and space no less. ER4SR on the other hand sounds a little more rigid and stiff, almost as if it is just slightly over-dampened. These are of course very subtle difference but it is to me the difference between being supreme vs. very good. I recalled I have the same (though much much worst) feeling regarding MC5, which technically has a very flat FR curve as well but it is nonetheless an overly dampened lifeless sound. I think the best description I can give on ER4S vs. ER4SR to me is alike a master pianist's rendition vs. that of a high precision self-playing piano.