Sample+synth-2. f m-3. additive-in the early 1980s sampling became a reality, but memory was expensive. roland quickly saw that new sounds would be possible if they could put a few cycles of sample at the front end of a sound and then do the sustain portion with subtractive synthesis. the roland d10 used this method successfully, they called their system linear arithmetic (l a).
yamaha went in a different direction, they hired a young computer genius called john chowning who pioneered frequency modulation synthesis. unfortunately this method resulted in great percussion and bell sounds, but poor string and brass. their fm synth (the dx7) was also really hard to program, so after an initial flurry fm was quietly replaced by other methods.
additive synthesis was a very attractive idea, unlike subtractive you could build the sound from the ground up by specifying partials (harmonics) of any relationship to the fundamental and at any amplitude. but this too was hard to program and ruinously expensive. wavetable synthesis was cheaper and easier to control and yielded similar results. vocoding is very old technology.
