Oberheim

Tom Oberheim's polysynths — fat, lush, unmistakable

Tom Oberheim built synthesizers for people who wanted their chords to sound like the sky opening up. Where Moog gave you the fattest bass and Sequential gave you precision, Oberheim gave you width, warmth, and a harmonic richness so dense it felt three-dimensional. The OB-X, OB-Xa, and OB-8 defined the sound of polyphonic analog synthesis at its most lush and expansive.

History

Tom Oberheim was a UCLA computer science graduate who fell into the music industry almost by accident. In the late 1960s, he started building ring modulators and phase shifters — effects units used by musicians in the burgeoning Los Angeles studio scene. His first synthesizer, the Oberheim SEM (Synthesizer Expander Module), was a single-voice analog synth module released in 1974 that could be stacked — two, four, or eight voices — to create polyphonic systems. These multi-voice SEM setups, particularly the Four Voice and Eight Voice, established Oberheim's sonic identity: warm, wide, and harmonically complex.

The SEM's filter was the foundation of the Oberheim sound. Unlike Moog's 24dB ladder filter or ARP's biting 12dB design, the SEM used a state-variable filter that could operate in lowpass, highpass, bandpass, and notch modes. This filter had a smoother, less aggressive resonance character that lent Oberheim instruments a distinctive warmth and width. When you stacked multiple SEMs together, the slight tuning differences between individual analog circuits created a natural chorus effect — a shimmering, cloud-like quality that became the Oberheim signature.

The OB-X, released in 1979, was Oberheim's first fully integrated polysynth (rather than a stack of individual modules). It offered up to eight voices with two oscillators each, and its sound was immediately recognizable — fatter and wider than the Prophet-5, which was its primary competitor. The OB-X became a staple of late 1970s and early 1980s rock and pop. The opening chord of Van Halen's "Jump" is an OB-Xa (the OB-X's refined successor), possibly the single most famous synthesizer moment in rock music.

The OB-Xa (1980) improved on the OB-X with better tuning stability, split and layer modes, and a redesigned voice architecture. The OB-8 (1983) added MIDI and further refined the design. Together, the OB series dominated the polysynth market of the early 1980s, competing fiercely with Sequential's Prophet-5 and later the Prophet-600 and T8. Prince was a devoted Oberheim user — the OB-Xa and OB-8 are all over Purple Rain and 1999, and their lush, expansive character was a perfect match for his maximalist production style.

The Matrix-12, released in 1985, was Oberheim's most ambitious instrument — a 12-voice polysynth with an extraordinarily flexible modulation matrix that allowed any source to modulate any destination. It was the most powerful analog synthesizer ever produced in terms of programming depth, but its complexity and high price limited its commercial success. Oberheim's financial troubles led to the company's sale to Gibson in 1985, and Tom Oberheim left the company he'd founded.

Tom eventually returned to building synthesizers under his own name, and the Oberheim legacy has been kept alive through various revivals and reissues. But the golden age — those five years from 1979 to 1984 when OB synths were the sound of ambition and luxury in pop music — remains one of the great chapters in synthesizer history.

Notable Instruments

OB-Xa

The OB-Xa is the Oberheim polysynth in its most refined form. Every improvement over the OB-X — better tuning stability, split keyboard capability, an additional filter mode — sharpened what was already a magnificent instrument. The OB-Xa's sound is unmistakable: thick, warm, and impossibly wide. Its pads hang in the air like clouds. Its brass sounds cut with a rich, brassy authority. Its bass is round and full without the aggressive low-end weight of a Moog.

Eddie Van Halen's synthesizer riff on "Jump" put the OB-Xa in the ears of every rock fan on Earth. But the instrument's real depth was in its pad and string work — those shimmering, evolving chords that filled the middle and upper frequencies of 1980s pop and rock productions. Prince's "1999" is drenched in OB-Xa. Rush used it on Signals and Grace Under Pressure. Queen's "Radio Ga Ga" features its rich pad sounds. The OB-Xa defined what "lush" meant in synth terms.

OB-X

The OB-X was rawer and more unpredictable than the OB-Xa — and many players preferred it for exactly those reasons. Its CEM-based voice cards had a wilder, less controlled character, and the instrument's tuning could drift in ways that added organic movement to sustained chords. Gary Numan used the OB-X extensively on Telekon and Dance, and its slightly unstable, atmospheric quality was a perfect match for his cold, futuristic aesthetic. Styx, Queen, and Talking Heads all featured the OB-X prominently, and its thick, meaty unison mode was one of the most powerful lead sounds available in the early 1980s.

Matrix-12

The Matrix-12 is the holy grail of analog polysynths for serious programmers. Its modulation matrix — with 27 sources and 47 destinations, freely assignable in any combination — offered a level of programming depth that no other analog polysynth has ever matched. Each of its 12 voices was independently programmable, the filters could morph between modes, and the two-oscillator-per-voice architecture could be coaxed into timbres ranging from conventional analog warmth to bizarre, almost digital-sounding complexity.

The Matrix-12 was the synth that synthesists dreamed about owning. Vince Clarke called it his favorite instrument. It appeared on recordings by Tangerine Dream, Jean-Michel Jarre, and Harold Faltermeyer. Its combination of massive analog sound and unprecedented programmability made it, in many ways, the ultimate expression of what analog synthesis could achieve. Only around 2,300 were ever produced, and they remain among the most valuable and sought-after vintage synthesizers in the world.

All Models in Archive (5)

Analog Synthesizers

• Matrix-12 - 1985-1988
• OB-8 - 1983-1985
• OB-X - 1979-1981
• OB-Xa - 1981-1984

Drum Machines

• DMX - 1981-1984