For me the bass level of Zero Blue is just fine (on Qudelix-5K) and bass extension is disappointing. On my laptop they are seriously bassy, I presume this is because of laptop's headphone jack impedance. If Zero Blue have too much bass to your years then I'd expect you to find that Zero:2 have even more bass - these IEMs rumble! And this is exactly how bass should be, as far as I'm concerned. :-D Then, again, we all listen at different levels - I usually don't listen too loud, may be that's why I think they don't have too much bass? I've never tried Red or these first Zero from this thread - and it sounds like I should not.