Context: I use these inears for my live band, i'm a guitarist but i like to hear everything clearly.
At first i ordered a pair of SD-2's, and i concluded i liked everything about them: the fit, the clarity, the isolation, except for one thing: a severe lack in low end, they sounded very thin.
So logically i ordered the SD-3 instead, hoping to get the same but with more low end. Unfortunately, the SD-3 lacks clarity, it has a very muddy and muddled midrange, transients feel dull, and the low end energy sits mainly in a bit of a muddy low mid place instead of where you'd want it to sit to feel a bit of kick energy. Everything sounds really balled up in the mids and small.
I really could not get myself to like how these sounded unfortunately.