I have been messing around with exciters. AS we get older those highs aren't quite as high anymore. I notice the mistakes - aside from horrible source tone or excessive scoops and boosts is: Really detailing the low end and top. The Low end takes a bit of experience, but with drum samples, keyboards and idiot=proof bass recording we are left with the top end.
I have tries exciters. Even boosting 20k on things that don't even go to 20k. First, never boost frequencies that aren't even there. Never cut anything you don't want to lose. Now the top end...the very top end.
This is a cool EQ. Forget all of the other EQ possibilities and view this simply as a 28k "kiss to the top of your tone".
Set it to "mastering mode" with 'keep gain" so your level doesn't increase - there is a trim know next to it if you need make-up gain. Mastering Mode made the increments less drastic, for fine tuning. The High dial lets you select 5 extra settings for that knob. Choose 40k. Take any stereo mix you are familiar with and boost 3db Do this for a song you loved on CD but are stuck with a compressed mp3 and watch it get CPR and spring back to life.
Perhaps 3bd is too much for you, but it will show you the difference. Clearly. Now Exciters are great for clearing up muddy upper mids, like a bunch of guitar tracks. However, guitar goes maybe to 16k? Now the effects will go to 20k, so this will clean that up. It helps on anything that goes to 20l, Overheads, full bandwidth effects. keyboards, etc. And of course your stereo buss. I toss this in right before the compresses so i can press the top into the mix. That is just me. I am a mastering engineer, so i am gong to compress last.
I would say for any pass you might record where attention over 16l might need a little kiss, add a db of this. Try it on your stereo bussing, and especially on your stereo buss out. Use the "top down method" - set your buss plugins first, then tweak your channels as everything will go through this buss anyway so have it on.
Just do this. If you don't like it, hit bypass, but now you have a choice. Its completely free, no ads or email needed. So really, if you don't get this you only have yourself to blame.