This is probably simple for most of you guys. Thing is i build a baseline in Logic in 16th notes and then put a kick to send its output to sidechain the bass. Thing is if i want to introduce the baseline after the kick is going the first note isnt ducked by the sidechain making it sound weird. Is this a sequence thing or side chain thing to make it work on first bass-note? The kick hits simultaneously as the first note btw...

Do you understand how compression works?

Ignoring the previous post, it's probably a glitch in your DAW. I use an older version of Cubase (still on SX2 believe it or not... ) and it does exactly that - but only sometimes. Previous versions of Cubase used to do it too. I find that often the first note in any midi sequence won't fire if it's at 0.0.0 and I start from stopped - sometimes it does it even when looping. It's easily fixed for when you're rendering by inserting a gap at the start - 1 bar will do (or less if you're prepared to fiddle about with part bars).
Or another way is to insert a midi delay on the whole project (I assume Logic can do that - I'd be surprised if it can't). Just a few ticks will do it. It may still miss out the first note for ducking when you're looping round, but it doesn't matter as long as you insert a gap for rendering. Another wayu I found was to simply move the first kick forward by one single tick - it stops the missed note and you really can't hear a difference in timing that small. And you only have to do it on the very first note.

It certainly sounds similar to my Cubase issue. It's a bit of a pain when it happens and you're looping sections for mixing and it keeps missing the first note, but I just got used to it and it doesn't bother me now. I never figured out why it doesn't always do it. It doesn't seem to do it if I drop in and out for recording either - just when starting from 0.0.0 - weird.

Oh, and you should probably check that midi priorities are set for note on being highest priority. I'd have thought nowadays that should be a standard default, but it may be that your Logic is set up to have priority for all kinds of other crap - midi note on should always be top priority.