As of late I've been playing gospel music for a few churches. See photos from the Jazz Vespers Services of May 2010.
The majority of jazz songs have chord progressions that may be complicated, i.e. highly altered chords or sections that in and of themselves stray greatly from "normal" progressions. Contemporary Gospel has songs that may have complicated progressions and at least in the songs that the Detroit Gospel group, Sounds of Unity, will perform this May in Milan, Michigan at the Men's Conference, many different sections within the songs.
The use of the diminished and augmented chords is both common and frequent. The changing of the bass line and therefore, bass note against a repeating chord progression leads to very interesting and rich sounding chords.
Notice that the bass note being played against the chords change from sustaining the F under the F7 and Bbmin7 and the E under the Cmin7 in the first line to the bass being the Eb under the F7, the Db under the Bbmin7 in the second line? The transition going the next set of progressions is the D under the Bb chord, an Ebmin7 chord and the changing to an E under a C chord.
In the sequence above I initially wrote it down as:
I was playing around the 1st fret and I could hear the Bbsus chord; but when I listened again and noticed the G in the bass, I changed the notation from Bbsus/G to Gmin7#5.
If I were writing the changes out for a guitarist who might not be familiar with a minor7 raised 5th, I would leave it written as Bbsus/G. I know that there may be an outside chance that I could end up playing this as the only accompaniment behind the vocalist; I changed my chart to reflect the Gmin7#5. I feel that dropping that Bb just above the low G seemed to open the sound a little; instead of the 1 - m3 - 7 the voicing is 1 - 7 - m3.
I do wonder if the frequent substitution of bass notes stems from organist playing; it does make it challenging for a guitarist who usually plays R&B, jazz, standards, rock and pop music. Challenging, but instructional; explore contemporary gospel and get some different ideas!
Until the next time, take care.