Of Form And Function

The use of different kinds of instruments has changed over time in the derivations of both rock and soul. However change has been much more limited in rock than in soul (and is even reflected in how frequently names for these genres are changed).

In rock and its sub-genres a band comprising vocals, electric guitars, electric bass, drum kit (with the occasional addition of the descendents of piano or organ) is almost mandatory. In contrast the kind of instruments utilized in soul and its sub-genres has changed markedly over time. In the 1960s a standard soul group may have consisted of electric organ, piano, electric guitar, electric bass, drum kit, tambourine, vocals, backing vocals, reeds and brass. By the 1990s more than half these instruments could be replaced in a soul recording by 'programming' (even if they were still a part of live shows).

The difference seems to be that for rock form is as important as function while in soul only function matters. So in a rock band particular instruments are necessary to produce the desired sound while in soul any instrumentation will do as long as the musical effect is right.

Another related difference is the status of musicians within rock and soul. In a rock band all members are supposedly as important as one another and recognized as contributing to the music. In soul the vocalists are of central importance however many instrumentalists they may have behind them. Hence solo performers and vocal groups are much more common in soul while rock is dominated by the 'guitar band' as the primary unit.