My first few minutes with these were a huge disappointment... They sounded worse than free earphones that come with MP3 players. Only after I switched to the included foam tips my mind was blown. I must've had them inserted wrong originally as when I re-seated them with the foam tips all sense of muddiness was gone. Instruments and vocals suddenly sprang to life, they were center-stage. Sound stage isn't excessively large, I would say "just outside of my head". I recommend vocal trance or anything with bright synths, as the T4 will make them shine like never before. If you like Hardstyle, dubstep, anything extremely bass focused, I recommend looking into the KBEAR KS2 instead, as that is the only other pair of IEMS that I carry with these T4s. The cable is pretty terrible, I immediately swapped them for a silver braided NICEHCK cable. They're hard, feel cheap, and are annoying to use because they keep their curly shape far too long after being packed tight in the case.
It's as expected, just perfect.