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Mopho X4 Analog Keyboard Synthesizer - Image 1

Mopho X4 Analog Keyboard Synthesizer

KeyboardAnalogPolyphonic

Dave Smith Instruments took the raw, single-voice Mopho monosynth and multiplied its analog heart by four, creating a compact powerhouse that delivers true paraphonic polyphony without losing that signature gritty edge.

At its core, it packs four voices with two voltage-controlled oscillators plus beefy subs per voice, routed through switchable 4-pole or 2-pole lowpass filters that sweep from subby depths to sizzling highs. Three snappy envelopes and four LFOs feed a deep mod matrix, while onboard delay, distortion, a 16-step sequencer, and arpeggiator keep things lively—all controllable via a knob-heavy front panel with instant access to key parameters, a crisp black-and-white display, and a 44-key velocity-sensitive keyboard featuring polyphonic aftertouch and fast action spanning over seven octaves with transposition. MIDI in/out/thru over USB and DIN, plus pedal inputs, make it a solid controller too; it's built tough at 25.2 by 11.1 by 3.6 inches and 13.5 pounds, with mono audio in, stereo outs, and headphones.

Players love its thick, aggressive tones for bass, leads, and pads with a modern DSI bite—thicker subs and unison detune modes turn heads, and the sequencer sparks ideas fast. The layout takes a session to master, but once dialed in, it's a hands-on joy that punches above its size in the analog poly world.

Released

2013

Status

Discontinued

Synthesizer
Format
Keyboard
Type
Subtractive
Internal Battery
No
Voice
A/D
Analog
Polyphony
Polyphonic
Oscillators
2
Oscillator Type
VCO (Voltage Controlled)
Voices
4
Filter
24dB/oct (4-pole), Lowpass, 12dB/oct (2-pole)
Envelopes
3
LFO
4
Effects
No
Expression
Aftertouch
Polyphonic
Velocity
Yes
MPE
No
Additional
44-key keyboard, 4-voice paraphonic, 16-step sequencer
Software
-
I/O
Audio In
mono
Audio Out
2x 1/4" unbalanced
Headphone
1x 1/4" TRS stereo
MIDI
In, Thru, Out
MIDI Type
USB, DIN (5-pin)
Ports
Sustain Pedal, Expression Pedal
Wi-Fi
No
Workflow
Arpeggiator
Yes
Sequencer
Yes
Mod Matrix
Yes
Memory
Yes
Measurements
Dimensions
25.2" L x 11.1" W x 3.6" H
Weight
13.5 lbs
Last updated Feb 25, 2026