Adrian, there's no clear cut answer because so much depends on the speakers you use, the room, type of music...however, there is a general consideration.
When talking about any EQ function, it's mainly about selecting the correct frequency for that particular instrument. For example, are you trying to enhance the sound of a piccolo or in your case a bass instrument? Bass instruments commonly produce frequencies in the 40 Hz to 400 Hz range. That’s not a complete analysis, but it’s a start. I suggest you select a few EQ channels (EQ 1 and EQ 2) and set EQ 1 to 60 Hz, EQ 2 to 80 Hz, and then boost both by 3 dB. Leave the Quotients at 0.1 for now. Test the new sound with a few styles or registrations and see how it sounds. Again, depending on your speakers, you’ll need to do some trial and error stuff. That’s a start.
Perhaps another member can add some thoughts?