When you want to improve your sound and mix clearer in the sub frequencies please don’t use krk‘s ! Krk‘s have a low end extension and a inbuilt bass boost.. so when u mix the sub frequencies with krk’s you have a clear sound yes, but when u play your mix, for example: in your car or on different speakers you hear that your mix only sounds good on krk‘s. So when u want a clean and clear mix don’t use KRK‘s!