Yamaha DX7: The FM Piano Sound of the ’80s

Everyone knows the bell-like, cool FM piano sound, often enhanced with effects and found in nearly every digital piano. This sound was modeled after the legendary Fender Rhodes but has a much brighter, more artificial character. The origins of all its countless variations can be traced back to the Yamaha DX7.

However, a closer look reveals that other Yamaha instruments of the time also used FM synthesis to generate their sounds, just like the DX7. Before the DX7 made FM sounds widely accessible, the vintage electric pianos GS1 and GS2 had already played a key role in popularizing the FM piano sound.

The FM Revolution

Loved and hated in equal measure, the FM piano sound in its myriad of variations simply refuses to die. In the 1980s and 1990s, it defined the sound of countless productions and became the signature of producers like David Foster. He worked with artists such as Celine Dion, Seal, Earth, Wind & Fire, Madonna, Michael Jackson, Barbra Streisand, and Whitney Houston (I Will Always Love You).

The FM Tines piano VST by Gospel Musicians is well worth exploring, as it offers an extensive collection of FM piano sounds. The included sound samples provide just a small glimpse of the many electric piano variations available.

As one of the first affordable digital synthesizers, the introduction of the Yamaha DX7 in 1983 ushered in a new era of synthesis. With its distinctive, elegantly minimalist design, it became one of the best-selling synthesizers in history and spelled the end for many of its analog competitors.

FM Piano Sound: Exceptionally Versatile

For keyboard players in the early 1980s who couldn’t afford the prohibitively expensive samplers of the time, the DX7 offered a practical solution. It provided access to a wide range of sounds, including organ, piano, strings, brass, various synth and FX tones, as well as percussive instruments like mallets and tubular bells.

The FM sounds delivered an unprecedented level of dynamic range and clarity—one of the key reasons behind the DX7’s massive success. It also was a perfect match for the sonic aesthetic of the era: In the ’80s, high frequencies were all the rage. What might sound harsh by today’s standards was highly sought after back then. Producers often struggled with treble loss in the studio, making devices like the SPL Vitalizer indispensable tools for sound processing.

Resourceful programmers continued to create new piano, brass, and string sounds that, at the time, seemed almost impossible to achieve on a synthesizer. A true cult following developed around the DX presets designed to emulate pianos. While many of these sounds may seem cheesy from today’s perspective, the FM piano presets have endured because of their distinctive character. They have long since become classics, earning their place alongside vintage electric pianos like the Fender Rhodes, Wurlitzer, and Yamaha CP-70/80.

The sheer variety of sounds also brought challenges in terms of storage. The DX7 could hold a maximum of 32 presets, with RAM cartridges available as plug-in expansion modules to increase its capacity.

Yamaha’s FM Model Diversity

Yamaha didn’t limit FM synthesis to the DX7—several other models featured it as well. Moreover, Yamaha later licensed the 4-operator version of FM technology (see below) to other manufacturers, further expanding its influence.

In addition to the desktop module version of the TX7, Yamaha introduced a rack-mountable expander. These units could accommodate up to eight TF1 plug-in modules, each containing a complete DX7 sound engine. The TX expanders were available in three configurations: TX216 (2 modules), TX416 (4 modules), and TX816 (8 modules). And the simultaneous stacking of eight FM voices, still an impressive feat today, really makes an impact.

FM Continues to Evolve

The DX7’s successor, the DX7IID, featured an improved audio converter, resulting in an even cleaner sound than the original. With a built-in floppy disk drive for convenient sound storage, the DX7IIFD was a definite upgrade.

The DX7s was the more affordable version of the DX7IID, while the TX802 served as its rack-mounted counterpart. Yamaha continued to incorporate FM synthesis in later models, including the SY77 and SY99.

Mini FM Synthesizers in the Past…

…And in Modern Times

To make FM synthesis available to an even wider audience, Yamaha developed an (affordable) streamlined 4-operator version. Used in synthesizers like the Yamaha DX21 and the iconic DX100, it was a true mini-key synth that was already available back then.

Yamaha also licensed its 4-operator FM chip to other manufacturers, allowing them to develop their own FM-based instruments. This led to synths with distinct sound aesthetics and user interfaces, such as the Korg DS-8 and Korg 707. The Italian manufacturer Elka, best known for the Elka Synthex, incorporated FM synthesis into home and combo organs throughout the ’80s and ’90s and even developed its own dedicated FM synthesizer series, the EK.

What Is FM Synthesis?

FM synthesis was developed in 1967 by Dr. John Chowning at Stanford University in California. Recognizing its potential, Yamaha quickly acquired the patent from Stanford. The first prototype was called the Programmable Algorithm Music Synthesizer.

In 1981, Yamaha introduced the GS1 and GS2, followed a year later by the more compact and affordable CE20 and CE25 FM instruments. However, the 1983 release of the DX7 was a game changer in the synthesizer world: Unlike its preset-based predecessors, it offered full programmability.

Each voice of the DX7’s 16-voice polyphonic digital tone generator uses six sine oscillators (or “operators”). These modulate each other, with 32 different interconnections or algorithms available. Depending on the selected algorithm, some operators act as carrier frequencies (carriers) and others as their modulators.

Very different sound spectra, consisting of complex waveforms, result from the frequency ratio of the carrier and the modulator.

The level over time, e.g., shaped by an envelope, then creates a sound that often resembles the sound response of acoustic instruments. This ability was also the reason for the huge success of FM synthesis back in the day. Using this principle, it was possible to create complex sounds that always had an organic-acoustic feel to them, even when they sounded ultra-electronic.

The same applies to the FM piano sound: While unmistakably electronic, it responds as dynamically as an acoustic piano. A well-known example is Ulla Meinecke’s Die Tänzerin, played and composed by music producer Edo Zanki. This iconic sound has inspired countless variations, many of them excellent—but the original remains unmatched. Interestingly, the song was reportedly not recorded with a DX7, but with one of Yamaha’s earlier FM electric pianos, the GS1 or GS2.

Current FM Synths

FM synthesis remains a powerful tool for creating a wide range of sounds. One of the most affordable hardware options today is the ultra-compact Korg Volca FM 2, which features a 6-voice DX7 sound engine and full compatibility with DX7 presets. The latter can be imported via the Dexed software (see below).

Korg also offers the Opsix, which features an advanced FM engine. Incidentally, you can also create FM pianos using the freeware Dexed or the powerful FM8 software synthesizer from Native Instruments. Arturia’s DX-7V is another excellent software recreation of the legendary synthesizer.

Of course, Yamaha also continues to use FM synthesis. Both the MODX and Montage workstation series feature a powerful, state-of-the-art FM engine with up to 8 operators. Meanwhile, the compact Yamaha Reface DX is a portable FM synth that packs a surprising punch.

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