The Oberheim DX brought digitally recorded drum sounds together with a sequencer designed for composing, editing and performing complete rhythm arrangements. Released in 1983, it provided a more affordable alternative to the Oberheim DMX.
At the centre of the Oberheim DX are recordings of real percussion instruments stored in memory chips. These sounds are triggered from dedicated front-panel buttons and organised into six voice groups: bass drum, snare, hi-hat, toms, cymbals and percussion. Each group offers three variations, giving 18 available sounds or playing variations. Only one variation within each voice group can sound at a time.
The factory bass drum and snare each provide three volume levels. The hi-hat offers closed, accented and open sounds, while the tom section provides three pitches. The cymbal group combines two ride cymbal levels with a crash, and the percussion group contains a shaker, an accented shaker and handclaps. These separate buttons allow changes in emphasis and instrumentation to be recorded directly into a rhythm.
Each voice has a rear-panel tuning control covering half an octave above or below its nominal pitch. Tuning applies to the voice group, allowing the drum kit to be adjusted without changing the programmed rhythm. The sound chips can also be replaced to change the instrument’s sound selection. Alternative chips offered different bass drums, snares, toms, hi-hats, percussion and effects, extending the available palette beyond the factory set.
The front-panel mixer provides a level fader for each of the six voices, alongside separate metronome and master volume controls. Stereo and mono mixed outputs carry the combined rhythm, while individual voice outputs allow the six groups to be routed separately to an external mixer. The voice and master faders control the mixed outputs without affecting the individual outputs, allowing separate treatment of the drum channels.
The Oberheim DX offers two recording methods. In real-time mode, a sequence loops while the player enters drum parts from the front-panel buttons. Existing notes remain in place as further parts are added, so a rhythm can be built over successive passes. Recording and erasing are separate operations, allowing an established pattern to be developed without automatically replacing earlier work.
Step recording allows notes and rests to be entered at individual positions. The step size follows the selected quantisation value, and several drum voices can be entered at the same position. Individual drum notes can also be removed in step mode, providing a way to correct a pattern without replaying an entire part.
Quantisation corrects incoming notes to the selected rhythmic division. It operates during recording, so different parts within the same sequence can be entered using different quantisation settings. The metronome subdivision is independent of the quantisation value, allowing the audible guide and recording resolution to be set separately. At the finest setting, timing resolution reaches 1/192 of a note.
Swing changes the relative timing of subdivisions to produce a shuffle rhythm. Like quantisation, it is applied during recording. The Oberheim DX also supports flam entry at its finer timing settings, adding a second note immediately after the initial hit. A selectable four-click count-in provides a lead-in before recording begins.
Editing facilities include erasing a selected drum throughout a sequence, removing notes as the sequence plays and deleting individual events in step mode. Recording can also be punched out into playback and resumed from the beginning of the sequence, allowing a pattern to be auditioned between recording passes.
The Oberheim DX stores up to 100 sequences and 50 songs. Sequences hold the actual drum performances, while songs contain ordered lists of sequences. This allows repeated sections to be reused within an arrangement without duplicating their note data.
Sequences within a song can have their own tempo, length and time signature. The tempo range extends from 25 to 250 beats per minute, and time signatures can contain between one and 99 beats per bar. These facilities allow arrangements to move between sections with different rhythmic structures.
The available recording duration depends on tempo and note density. Memory holds approximately 2,200 events, with each event capable of containing up to six simultaneous notes. Battery-backed memory retains programmed material when the power is switched off, while a rear-panel memory protection switch prevents changes to stored programmes. Tape storage provides a means of saving and reloading rhythm data.
External clock inputs and outputs allow the Oberheim DX to exchange timing signals with compatible equipment. Clock resolution can be set to 24, 48 or 96 pulses per quarter note. Tape synchronisation allows programmed rhythms to follow a synchronisation signal recorded on tape.
The programmable metronome output can also provide clock pulses for external equipment. It can follow regular note divisions or be programmed to respond to selected drum events, allowing devices such as arpeggiators to follow an uneven rhythmic pattern.
An external trigger input can be assigned to a drum sound and operated from a compatible inverted trigger or footswitch. Separate footswitch connections provide start/stop control and advancement to the next sequence or song.
MIDI-equipped versions of the Oberheim DX provide MIDI input and output for playing drum sounds from keyboards, MIDI drum pads and other controllers. MIDI note assignments are programmable, and incoming notes can be recorded into sequences. MIDI also supports timing, song changes and programme transfer on these versions.
Features
- Digitally recorded drum and percussion sounds stored in replaceable memory chips.
- Six independent voice groups with 18 sound variations.
- Factory bass drum, snare, hi-hat, tom, cymbal, shaker and handclap sounds.
- Individual voice tuning covering half an octave above or below nominal pitch.
- Six voice level faders, metronome level control and master volume control.
- Stereo and mono mixed outputs plus individual outputs for each voice.
- Real-time recording with successive overdubs and single-step programming.
- Selectable recording quantisation, swing and flam entry.
- Independent metronome subdivision and optional four-click recording count-in.
- Storage for 100 sequences and 50 songs.
- Programmable tempo, sequence length and time signature.
- Battery-backed memory, memory protection and tape programme storage.
- External clock input and output with selectable pulse resolution.
- Tape synchronisation and programmable metronome pulse output.
- Assignable external drum trigger and footswitch control.
- MIDI note control, synchronisation, song changes and programme transfer on MIDI-equipped versions.
