I suspect the OP needs to adjust the Bass-Midi not a RT Audio Bass. If that is the case, then the same menu shown above will work, but you need to click on "Edit Midi" to raise the Bass an octave.
Let us know which it is? We tend to keep score on who guess correct. grin


BIAB – 2025, Reaper (current), i7-12700F Processor, 32GB DDR4-3200MHz RAM, Motu Audio Express 6x6 - My SoundCloud (Tip: No need to create a SC account to hear music - just hit ESC ).