Realizing a Figured Bass
First, re-read the chapters on figured bass at the end of the first book:
6D Figured Bass Chord Progressions
Armed with this information, you can now realize a figured bass by determining how to voice chords into the treble clef, as if you were performing the figured bass at the keyboard. The concept of realizing a figured bass is this: write into the treble clef that basic chords that an experienced figured bass player would know how to improvise at sight, given just the bassline and the figures.
Here is a bassline with figures, followed by a simple realization. Notice that the chords are all voiced with three notes, and that care is taken NOT to move root position triads in parallel motion, which result in parallel fifths that are not used in this style. In general, you will voice a lot of chords with the third on the bottom or on the top. If the third is in the bass (that is, if the chord is in first inversion), it is OK to leave it out of the right hand if it makes for smoother voice leading.
In this example, the eighth notes on the 'and' of beat two in measures 3 and 7 are just passing notes and do not require a harmonization. Here is how this would be realized. Study the figures and make you are clear why the treble clefs note are chosen.
Finally, here is a realization of the complete first recitative from Bach's St. John Passion, which we listened to in class. Open this PDF to compare the original score with the realization. A straight (off the Sibelius file) playback of the audio is below the example. Listen to it, to match what you see with what you should hear.
NEXT: 2C Comparing Figured Bass notation and Jazz Charts