Hi, just bought a Shure 535, to finally replaced my antique E4C. I mainly use IEM with my A&K Junior. The issue I have is the 535 is much louder than E4C, and the sound is really bright and harsh. I know maybe break-in some time may help, but really surprised the latest Shure sound when it compares to the ancient IEM from Shure. I mainly listen to acoustic music, classical and Jazz.. I checked 535 impedence is 35Ohm, while E4C is 29Ohm, I compared my other headphones such as HD580, 600, HD25-1 II... the loudness and impedence numbers are matching. However this 535 is weird. I bought mine directly from Amazon I know many from eBay are fake. The main difference from 535 to my aged E4C: treble more delicate sparkles from E4C, the cymbals are more airy too. the mid bass, 535 has more weight, but the mid frequency E4C is fuller. lower bass, 535 has more weight but E4C has more details. I hope I'm wrong with 535, maybe I need to replace cables or run-in can make big difference ??