How well does it represent kick drums and electronic drums? Is it deep and realistic or slightly undercooked?
There's nothing "undercooked" about Isa's bass to my ears. I'm listening to "One" by Metallica right now with Isa and can feel the thud of the kick drum in my chest. The sub-bass does't necessarily grab your attention due to a subtle mid-bass emphasis but when you focus on it everything is there and it's got extension & texture for days. That said this is not an IEM one goes for if they're specifically looking for bass to be the star of the show-- it's not. IMHO the midrange/vocal presence & naturalness and overall tonal balance is the star of the show with Isa-- with the bass ultimately serving a supporting role, but doing it phenomenally imho. I've also got an Oriolus Reborn on hand and have been totally floored by how good the bass is, particularly the sub-bass in this case.