Sorry if what I say here is really obvious, but it’s not clear from you question how much you know / don’t know …
More obvious: my hihats go down to the 35hz range. Can be sorted with a hpf but not really good sounding afterwards…
What am i doing wrong.??
Nearly all sounds have some low frequency content, especially percussive sounds.
Obviously each channel is summed at the master bus and that includes all the low frequencies which haven’t been removed. It’s the build up of these low frequencies (and high …) that causes muddiness in the overall mix.
There is not much you can do about this except use a filter or EQ to remove the frequencies you don’t want / need from each channel. The more you cut, the clearer your mix will be - within reason. Remove to much and the over all mix won’t sound very “full”.
For hi-hats and similar percussion I would typically start with a low shelf EQ at 1000 Hz and move up from there - really depends on the sound I want.
Some articles that you might find useful:
http://www.homestudiocorner.com/linear-phase-vs-regular-eq/
Peace,
Andy.