i’ve heard a p bass in the mix hundreds and hundreds of times, and i could always identify where it was; nestled right in-between the bass drum and the snare drum. a nice cozy little spot. but when jazz basses come foward, you know the bass is there... but where is it? if the bass wasn’t there you would immediately know, but still i don’t know where it is.
Listen to Rush on Moving Pictures.
This is when GL switched to a Jazz from his Ric.
I believe, maybe wrongly, that 'Red Barchetta' is the only track with the Ric and everything else is the Jazz.
On albums after this he used Wal and Steinberger, but starting on Counterparts he used the Jazz exclusively on albums.
Others here, more expert on Rush than I, would have more details.
You feel the bass. Others have explained it in sound frequency as in low Hz, but you also hear bass in midrange and depending on strings and pups even in treble. Just listen to a Ric with Rotosound swing 66 strings.
Rush without a Bass would be even more noticeable as being absent as the Bass is not only rhythmic, but also melodic.
Listen to music on a good sound system rather than earbuds and you'll know where the bass is.
For a P bass example, listen to Kansas' first 5 albums. Dave Hope plays a Precision with a pic and you can hear and feel the bass. For the longest time I thought he played a Jazz, but his pic playing style and EQ really come through.
Using round wound or flat wound strings really makes a difference too.
Roto swing 66 strings really ring out from bass to treble.