Here’s an example of a riff-oriented approach (reprised from The Art of Groove, Level 2).

Audio Example 1

 

Speaking of Level 2, notice the use of the meat & potatoes groove intervals? To my ear, the bass line strongly implies minor pentatonic (despite the absence of a b3). However, it would also function equally well under a dominant 7 vamp.

A more bombastic, driving 8th note approach might sound like this...

Audio Example 2

 

Audio Example 2 (Drums)

 
 

Note the use of a pick, and a loose phrasing that conveys a sense that the “wheels are just about to come off”. This type of bass line emotes to a much greater extent if flawless execution takes a back seat to really saying something. The groove in this example is played on top of the beat. You’ll also notice the use of slides to the upper register, another idiom in this type of rock feel.

IDIOMS

RHYTHMIC:

Usually based around an 8th note subdivision feel.

Phrasing varies, but generally on top of the beat for driving, up-tempo tunes and laying back for slower tunes/ballads.

HARMONIC:

Usually fairly diatonic, but not a lot of “pretty” chords (Maj 7, etc.). Normally wouldn’t find a lot of chromaticism. Current rock frequently incorporates tension by substituting “2" chords (e.g., D2, F2, etc., comprising the root, 2nd and 5th only) for major chords. Consequently, 9th‘s can be a good choice when embellishing. Heavier or edgier rock commonly injects b9's and b5's for tension, as well. However, most mainstream examples employ fairly inside, diatonic harmony.

SONIC:

Rock tone generally has some drive/edge. Dig in and move air, but also ensure that fret buzz doesn't get out of hand (particularly if the engineer will be copiously compressing your signal). Low mids (around 250 hz) can give clarity and focus. For extra bite, boost some of the upper mids (around 800 hz). Experiment with those frequencies, as the acoustics in the venue are a big variable. Tube overdrive (whether actual or simulated) can add some nice edge, but be appropriate for the context.

GENERAL:

The Rock genre is fundamentally about energy, edge and attitude. When playing a rock groove, try not to be overly clean with your technique - that can sometimes diminish from the rawness and attitude. Sliding into notes in the upper register (usually on the lower strings) is a common phrasing idiom in a driving rock feel and sounds huge in the proper context. A riff-oriented approach can be effective in this genre, perhaps to a greater extent than in most other styles.