I've mixed on headphones for so long. Now I've finally got some great new to me JBL LSR308 monitors. I'm going to get a bigger desk and/or some stands as it's uncomfortable and a mess in there now. So far I've listened to some favs on YT and some forum member songs on Soundcloud etc. The sound of these speakers and depth of the sweet spot is amazing. Other than the slightest vibration I can feel in the wood they're sitting on because I haven't put any isolation under the speakers yet I'm amazed how great they sound already.

The only thing I've really noticed so far is my headphones sound just a little bit brighter on all those same songs. How do I know which is telling my ears the truth? How do I know if I should change the bass and treble switches on the back or leave them at center (flat)? I know these may be dumb questions but I don't know so I'm asking.

I'd like any pointers and tips you may have on making the transition from mixing on headphones to real monitors. I really want my mixes to be better and get to the next level so any helpful advice you can give me on this transition is appreciated very much. Thank you.