That’s a very subjective subject, so here’s my perspective on the subject.
What is it you are trying to play, the mandolin or the studio?
Good studio artistry can cover-up a lot of musical errors, and there is a place for that. But often it becomes the primary instrument rather than the back-up. When that happens you tend to get a piece that is over-produced, over compressed, too much reverb and an overall loss in the unique sound of the acoustic instrument.
A former English teacher of mine had a simple rule regarding the use of commas. “When in doubt, leave it out.”
The same applies to salting food when cooking.
It also applies to EQ & other seasonings for a properly prepared piece of music.
After all, there’s not much EQ on the mandolin when you are playing face-to-face with Sam Bush!
Thoughts in a random order: Almost always use an EQ to cut as opposed to boost frequencies as it is much less prone to fake sounding tones. To my ear, I like to clear space for vocals (or lead instruments) around 800 to 1k by reducing backing instruments in those frequencies. A mando is not a deep instrument, don’t try to make it sound like one. Use a high pass around 175hz to get rid of noises it shouldn’t make anyway. I think I would typically end up making a mild cut by ear somewhere about an octave up from that (maybe 400 or 500 ish). Then use a wide brush to adjust high frequency (2k+) and that would be a good starting point. Use your ears. Listen to your favorite recordings to compare to what you are getting. Like Banjoe suggested, play it like Sam Bush Here’s the fun part: try a bunch of different mics and positions… it makes a world of difference.
You wouldn’t want to be around when I am seasoning a brisket
I buy salt in bulk.
This is way over my head! except for the Brisket part ! MMMMMMMMMMMMMMM BBQ!