If the pedal tone is the root note of the “I” chord, it is called a tonic pedal point (e.g. in the key of C, the C note). Tonic pedal point progressions are created by making the root note of the “I” chord the bass note of each chord in a progression by using various chord substitutions including inversions, embellishments, and chord quality changes.
The resulting chord symbols are so called “slash” chords. The chord before the slash is what the guitarist or keyboarder would play. The letter after the slash is the note the bassist plays.
More on slash chords on this blog, here!
Here’s a simple 1-4-5-Progression in C major with a tonic pedal point:
Here’s an analysis of how each triad reacts to the C bass pedal:
To play a more interesting bass pedal you can spice up the basslines with octaves or fit in some chord tones in the second half of the bar:
Here some more ideas for the same progression in slower tempo:
The previous examples only used diatonic chords of the corresponding key. But the bass pedal point also works with non-diatonic chords: