Watch the Black Dress online guitar lesson by Andrew Ford from 30 Rock Bass Grooves for Beginners You MUST Know
This is a groove based on the Hollies song "Long Cool Woman". The bass in this groove has a sort of two beat feel, like each bar is divided into two sections, giving it this strolling quality. It's not pushing or driving the steady quarter or eighth notes, it's a whole different groove. It's mainly centered around half notes until Bar 4 where it again sets up the beginning as it comes back around. We start on E minor for the 1st two bars, and the half notes alternate between the root E, and go down to the 5 (B) - same fret, just one string lower.
In Bar 3, we have two chords, G for two beats and A for two beats, using the roots for each. Then, in Bar 4, we begin with a half note over the root, E, then a pattern that turns us back around by using eighth notes using the 5 (B) for the two eighth notes and for the last two eighth notes we use D, that b7 we've talked about, and then a half step, chromatic note that leads back to E. So, the change in rhythm and note choices gives us the variety we need to indicate something new is about to happen.