By the middle 1970's it had become apparent that the dominant instrument of the era and thereafter would be the syntheisizer. This was for two reasons:
This class of instruemnt was found in just about every type of popular music from Jazz to Classic/Progressive Rock and even (ewww!) Disco and was used by even the dreaded Carpenters.
- The synthesizer had a wide range of sounds, both imitation of other types of instruments and unique to itself
- The term had been expanded to include instruments that one would not think of, such as string ensemble keyboards like the Solina IV and instruments like the Polymoog that processed output from organ-based tone generators through the synthesizer modules, notably filter and envelope generators