If you’ve listened to any 80s song ever, you have definitely heard the sound of the Yamaha DX-7. The DX-7 was the first digital synthesizer made accessible and affordable for a wider audience. It was also the first mass-produced FM-synthesizer ever. Til the end of the 1980s, it had become fully ubiquitous, since it could be heard on almost every pop-song of the decade. 

What made it so interesting, were its capabilities to realistically emulate acoustic bell-, string-, organ- or flute-sounds, as well as membranes and metallic plates or beams. In a musical dominion of subtractive synthesis, this instrument opened up a whole new world and sound aesthetic. The DX-7 is 16 voice polyphonic, has (and needs) no filters, holds 32 presets and supports MIDI. Its very complex algorithm-programming (sound design) and the limited (and quickly overused) set of stock presets opened up an entire market for sound designers deep diving into the instrument, making and selling presets.
Some of its most famous users, amongst hundreds of others, were Whitney Houston, Michael Jackson, A-ha, Madonna, Europe, and Stevie Wonder.