Alternatives to SynthMaster One

Cardinal

Cardinal suits musicians who want a free modular synth as a standalone app or conventional audio plugin, with a large bundled module set.

Dexed may suit synth users seeking a DX7-oriented plugin or standalone instrument, as well as DX7 owners managing SysEx programs.

Helm suits computer-based electronic music makers who want a free synthesizer in standalone or plugin form.

SynthMaster 3 suits musicians looking for a modular synthesizer with multiple synthesis methods, editors, and DAW routing.

Vital

Vital suits sound designers and musicians seeking a wavetable synth with extensive modulation, MPE, or microtonal tuning support.

Aalto suits musicians and sound designers seeking modular patching, per-voice sequencing, and expressive oscillator and filter controls in a plug-in.

Surge XT

Surge XT suits sound designers and music makers looking for a synthesizer plugin, including those who need MPE or microtuning support.

Repro suits music makers who use host software and want two modeled synthesizers in one plug-in.

ABYSS 2 suits musicians and sound designers working in compatible macOS or Windows DAWs.

VCV Rack

Rack suits people who want to build modular synthesizer patches for learning, performance, or composition, with optional hardware and DAW integration.

Sonic Pi suits people making music with code, from learners in computing or music lessons to professional musicians and DJs.

It suits electronic-music producers using a compatible plugin host on Windows or macOS.

Synth1 suits computer music producers using a DAW with VSTi or AU support.