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Dave Smith Instruments Mopho x4 44-Key 4-Voice Polyphonic Synthesizer

Dave Smith Instruments Mopho x4 44-Key 4-Voice Polyphonic Synthesizer

$655.00 Price Tier: Standard

3 Critic Reviews

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Page last updated Jul 02, 2026

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5.0 (8)

$655.00 6 available Used

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Average Price: $655

Standard/Professional

$500

$1501+

Price Tier

In the Synthesizers category, Dave Smith Instruments Mopho x4 44-Key 4-Voice Polyphonic Synthesizer is priced in the Standard/Professional range. This is quality gear at a fair price point, suitable for beginners, hobbyists, and pros alike.

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Description

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Unleash your sonic creativity with the Dave Smith Instruments Mopho x4, a 44-Key 4-Voice Polyphonic Synthesizer that merges classic analog warmth with modern versatility. Designed by renowned synth pioneer Dave Smith, this compact powerhouse delivers a rich analog signal path, providing musicians with the depth and dynamism needed for immersive soundscapes. Whether you're crafting colossal bass lines, intricate sequences, or ethereal pads, the Mopho x4's robust features ensure your musical vision comes to life.

With 44 semi-weighted keys offering aftertouch, the Mopho x4 invites expressive performances that respond to every nuance. Each voice is equipped with two analog oscillators and two sub-octave generators, all passing through genuine Curtis lowpass filters, allowing for a broad spectrum of tonal possibilities. The onboard relatchable arpeggiator and 16 x 4 step sequencer fuel your creativity, while the expansive modulation options, boasting 20 sources and nearly 50 destinations, open up avenues for sonic exploration.

For those seeking even greater depth, the Mopho x4 is expandable via its Poly Chain port, seamlessly integrating with other Dave Smith instruments to create a polyphonic colossus. Whether in the studio or on stage, this synthesizer stands ready to elevate your music with its blend of classic analog sound and modern ingenuity.

Key Features:

44 semi-weighted keys with aftertouch for expressive playing
4 voices, each with 2 analog oscillators and 2 sub-octave generators
Genuine 2/4-pole-selectable Curtis lowpass filters
Extensive modulation options with 20 sources and nearly 50 destinations
Relatchable arpeggiator and 16 x 4 step sequencer
Expandable polyphony via Poly Chain port
USB 2.0 for MIDI communication with computers
Designed and manufactured in San Francisco, USA

Product specs

Brand	Dave Smith Instruments
Model	Mopho x4 44-Key 4-Voice Polyphonic Synthesizer
Year	2013 - 2018
Made In	United States
Categories	Analog Synths, Keyboard Synths
Analog / Digital	Analog
Key Size	Full Size
Keyboard Action	Semi-Weighted
MIDI I/O	MIDI Input, MIDI Output, MIDI Through, USB MIDI
Number of Keys	44 Keys
Polyphony	4 Voices

FAQs

Is the Dave Smith Mopho x4 suitable for live performances?: Yes, the Mopho x4 is well-suited for live performances thanks to its 44 full-size semi-weighted keys and robust analog sound engine, providing a versatile and expressive playing experience.
How does the polyphony of the Mopho x4 affect its sound capabilities?: The Mopho x4 offers 4-voice polyphony, allowing you to play four notes simultaneously, which is ideal for creating rich, layered sounds and complex chord progressions.
What kind of sound engine does the Mopho x4 use?: The Mopho x4 uses an analog sound engine, delivering warm, organic tones that are characteristic of classic synthesizers, perfect for a wide range of musical styles.
Can the Mopho x4 be integrated with a computer-based setup?: Yes, the Mopho x4 can be easily integrated with a computer setup via USB MIDI, allowing for seamless connectivity with DAWs and other MIDI-compatible software.
What are the key features of the Mopho x4's keyboard?: The Mopho x4 features a 44-key semi-weighted keyboard, providing a responsive and expressive playing experience suitable for both studio and live environments.

Videos

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Sequential

Mopho x4 Demo- Dave Smith Instruments

Sequential

DSI Mopho x4 Demo with Peter Dyer

Sequential

Mopho X4 Demo

JRR Shop

DSI Mopho X4 (user presets)

Hadron Orchestra

Dave Smith Instruments Mopho x4 – 1 Hour Synth Exploration | Sound Demo

Mr. Card Synths

Reviews

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PROS

Rich, full sound that exceeds many virtual analog counterparts
Durable, solid build quality; feels like a living instrument
Highly portable, great for touring musicians
Extensive modulation capabilities with 4 LFOs and a comprehensive modulation matrix
Easy access to controls with minimal menu diving
Seamless polychaining, perfect for expanding sound capabilities
Versatile in producing leads, bass, and stab sounds
Knobs allow for on-the-fly tweaking during performances
Distinct sound with atmospheric potential, especially with external effects
Great value for an analog poly synth

CONS

Onboard sequencer is cumbersome and lacks a latch button
No built-in effects, requiring external solutions for enhancement
Workflow requires some practice to become intuitive

Owner Insights

We analyzed real musician discussions from forums and Reddit to find what players love, question, and tweak about Dave Smith Instruments Mopho x4 44-Key 4-Voice Polyphonic Synthesizer.

Features and functionality

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The Mopho X4's modulation options include 4 LFOs, velocity and aftertouch sensitivity, a sequencer, and an extra envelope for enhanced sound design capabilities.
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The Mopho X4's interface may not be intuitive for beginners, as some users find the panel layout challenging for programming compared to other synths.
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The Mopho X4 includes CV input, which can be utilized with an expression pedal for additional modulation control, a feature appreciated by hands-on players.
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Each of the Mopho X4's oscillators offers a wide range of ten octaves, with dedicated suboscillators at -1 and -2 octaves for each voice, enhancing its bass capabilities.
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User experience

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Some users report jumpy encoders affecting filter values, which can be addressed with firmware updates or professional repair, with Sequential's support being praised for affordability.
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Comparisons

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The Mopho X4's 4-note polyphony with dual oscillators and sub oscillators can produce a thick sound, but lacks the flexibility and power of the 8-voice Rev2.
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The Mopho X4 is described as having a harsher, more metallic sound compared to the Moog Sub Phatty, which is noted for its warm, smooth tones.
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The filter placement on the Mopho X4’s panel is unconventional, located at the bottom right, which some users find counterintuitive compared to traditional synth layouts.
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Some users find the Mopho X4’s interface less intuitive compared to the Novation Bass Station, noting the use of a single set of envelope knobs for multiple functions as a compromise.
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Use cases and applications

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The Mopho X4 is favored for its compact size, making it suitable for mobile setups and easy transportation for gigs.
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Owners suggest the Mopho X4 is better suited for sound design and production, offering more features like an internal sequencer, aux envelope, and arpeggiator.
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The Mopho X4 can be polychained with a Tetra to expand its polyphony, making it a flexible option for future growth.
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Build quality

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The Mopho X4 is noted for solid build quality and a reliable keybed, providing a satisfying tactile experience.
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Some users find the Mopho X4 easier to program than the Moog Sub Phatty, as all functions are visible on the display without hidden features.
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The Mopho X4 features wood and metal construction, contributing to its significant weight, which some users find adds to its robust and premium feel.
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Critic Reviews

Dave Smith Instruments Mopho X4

soundonsound.com

The Dave Smith Instruments Mopho x4 impresses with its compact yet powerful design, offering four polyphonic voices in a portable package. Its robust construction and quality sound are standout features, with a rich library of factory sounds and user memories. The synthesizer's layout feels counterintuitive, and the lack of sequencer latch is a minor drawback. However, its versatility and the option to expand with a Tetra make it a solid choice for synth enthusiasts. While not the cheapest option, its quality and performance justify the price. A modern classic in the making.

positive

Full Review

Dave Smith Instruments Mopho X4 review | MusicRadar

musicradar.com

The Dave Smith Instruments Mopho x4 strikes a harmonious chord with its solid build, potent sound, and attractive price point under £1,000. Musicians will appreciate its compact form, sequencer, arpeggiator, and robust modulation section. However, it lacks multi-timbrality and an audio input, which might deter those seeking versatility. Its 44-note semi-weighted keyboard is praised for its high-quality feel, and the synth's sound is described as bright and punchy, thanks to features like sub oscillators and a feedback circuit. This synth is a brilliant choice for those looking for a well-rounded four-voice polyphonic experience without breaking the bank.

positive

Full Review

Review: Dave Smith Instruments Mopho x4 | Juno Daily

juno.co.uk

The Dave Smith Instruments Mopho x4 stands strong as a versatile, polyphonic analogue synth. Its four-voice polyphony and robust sound engine, featuring digitally controlled oscillators with sub oscillators, offer rich and varied tones. The Curtis low-pass filter and a well-designed modulation section make it a sound designer's dream. While its sturdy build and classic design are commendable, the feel of the knobs and buttons leaves something to be desired. The interface is intuitive but patch navigation can be clunky, with some sound bleed issues. Despite these minor setbacks, the Mopho x4's portability, comprehensive connectivity, and performance-ready features make it a solid choice for those seeking a modern yet classic analogue synth experience.

positive

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