What does 'gain resonance' actually mean? How do you measure it? Is it a good thing?
The problem is resonance has two essentially different meanings in this context so we iften have different understandings of what we are discussing.
In physics:
"the reinforcement or prolongation of sound by reflection from a surface or by the synchronous vibration of a neighbouring object."
You measure it by applying different frequencies. E.g. play lots of notes and see which ones sustain longest. These will be the resonant frequencies.
The ideal for a bass is the same as a speaker cab - to not have any marked resonances that cause particular notes to be exaggerated, causing other notes to seem muted.
In music:
"the quality in a sound of being deep, full, and reverberating."
So yes we want that... but what does it actually mean for instruments? For an acoustic instrument it chiefly means a highly responsive sound board, (with no strong frequency resonances).
For an electric instrument it's really just about reasonable sustain (how much do you need?) and a lack of dead spots.
So to 'sound resonant' you want to minimise any 'resonants'.
😁