First is the source, the bass itself. Most players imagine their sound in a vacuum. Unfortunately what sounds good solo in their bedroom has little in common with what is needed at the concert hall. When bands practice there is seldom enough thought given to how the instruments blend, who will fit in where in the sound spectrum. Guitarist thrill with extended bass in their sound, while bassists think that every sibilant nuance of their new strings must be broadcast to the masses.
Drummers rightfully cover the spectrum from bass drum to high hat.
The result is that no one is heard correctly, a volume race ensues in the practice room and on stage. We could start by taking our cues from the electric bass pioneers of the 50s and 60s who, with modest equipment were able to propel their music in a most effective and memorable way, often using short scale basses or hollow bodies and flat wound strings of prehistoric vintage that they played with felt picks. Few of us today would stand for dead strings but we should consider that much of a new string's sound is high frequency clutter. On stage most of those highs will be masked by the guitar, cymbals and other high frequency sources. Trying to poke through the mix by boosting mids and highs won't clear up the bass part since the upper content is mostly finger noise, sympathetic ringing from adjacent strings and buzz or hiss.