Helm
Helm is a free software synthesizer for making electronic music on a computer.
What Helm is
Helm is a free software synthesizer for making electronic music on a computer. It runs as a standalone app or as a plugin in LV2, VST, VST3, or AU formats, with GNU/Linux, macOS, and Windows versions available in 32-bit and 64-bit editions. Its sound tools include dual oscillators with cross modulation, unison, a sub oscillator, filters, modulation, a step sequencer, an arpeggiator, and audio effects. MIDI Learn lets you assign a MIDI control to a knob or slider. The maker describes Helm as DRM-free software that users can study, change, and redistribute in original or modified form. Its FAQ says the person who plays a sound created with Helm holds its copyright. Listed requirements include Windows 7 or later, macOS 10.7 or later, Ubuntu Trusty 14.04 or later, and Debian Jessie or later. The project is described as a beta release with outstanding bugs. The maker asks people reporting bugs to provide details such as their operating system and whether they use the plugin or standalone version.
Good
- Free to use, with no DRM.
- Available as a standalone app and several plugin formats.
- Includes oscillators, filters, sequencing, and audio effects.
- MIDI Learn maps controls to knobs or sliders.
- Created sounds belong to the person who played them.
Watch out
- The project is described as beta with outstanding bugs.
- Listed system requirements start at Windows 7 and macOS 10.7.
Who it suits
Helm suits people making electronic music who want a free synthesizer with standalone and plugin options. It may also appeal to users who value software they can study, modify, and redistribute.
Verdict
Helm offers a broad set of synthesis and modulation tools at no required cost. The beta status and outstanding bugs are worth considering before choosing it.
Plans and prices
From Helm's own pricing page, checked 15 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Pay what you want | — | Standalone or plugin download · no DRM · pay nothing permitted · Optional contribution; page displays $5 input and $10, $25, $50 and $100 amounts |
The facts
Each one read from Helm's own pages, with the date it was checked.
What it does
- Build requirements
- The source build instructions require platform build tools; AAX builds need the AAX SDK and macOS AU builds need Apple's CoreAudio SDK.checked 15 Oct 2026
- Created sounds
- The FAQ says sounds created with Helm belong to the person who played them, who holds their copyright.checked 4 Oct 2026
- Documentation depth
- The official manual is a 32-page v0.9.0 PDF covering synthesis modules, modulation, patch browsing, audio settings and performance controls.checked 15 Oct 2026
- Effects
- Built-in effects are formant filtering, stutter, distortion, delay and reverb.checked 15 Oct 2026
- Filters
- Helm provides blendable 12 dB and 24 dB low-, band- and high-pass filters plus low-, band- and high-shelf filters.checked 15 Oct 2026
- Known limitations
- The GitHub project description says the release is in beta and has outstanding bugs.checked 4 Oct 2026
- Licence
- The source repository identifies Helm as GPL-3.0 licensed open-source software.checked 15 Oct 2026
- License and DRM
- The maker describes Helm as free software that can be run without DRM, studied, changed and redistributed in original or modified form.checked 4 Oct 2026
- Limit: learning curve and interface
- Equipboard reviews mention a steep learning curve, while another reviewer calls the interface visually cluttered or unattractive.checked 15 Oct 2026
- Limit: maintenance
- GitHub shows the official repository was archived and made read-only on February 8, 2025.checked 15 Oct 2026
- Limit: premium feature gap
- Data Broth says newer free instruments such as Vital and Surge offer substantially more capability, while AudioTechnology's summary says Helm lacks some premium-level polish.checked 15 Oct 2026
- Limit: sound character
- Data Broth describes Helm as mainly digital and harsh, with limited usefulness for analog-style sounds.checked 15 Oct 2026
- Limit: stability
- The project README warns that the release is beta and has outstanding bugs.checked 15 Oct 2026
- Limit: Unity availability
- Unity marks the Audio Helm asset deprecated, unavailable for purchase and unsupported by its publisher.checked 15 Oct 2026
- MIDI control
- The manual explains how to map a MIDI control to a knob or slider using MIDI Learn.checked 4 Oct 2026
- MIDI learn
- The manual describes right-click MIDI Learn for assigning a hardware MIDI control to a knob or slider.checked 15 Oct 2026
- Modulation
- Modulation sources include two monophonic LFOs, one polyphonic LFO, three envelopes, keyboard controls, random values and polyphonic aftertouch.checked 15 Oct 2026
- Notable news
- Matt Tytel announced the rebranding from Twytch to Helm on May 8, 2015.checked 15 Oct 2026
- Oscillators
- The synthesizer has two oscillators with cross modulation and up to 15 unison oscillators per oscillator.checked 15 Oct 2026
- Plugin formats
- The official site distributes Helm as standalone software and LV2, VST, VST3 and AU plugins.checked 15 Oct 2026
- Polyphony
- Helm supports 32 simultaneous voices.checked 15 Oct 2026
Where it runs
- Limit: high-resolution Windows GUI
- A KVR reviewer reports that Helm's interface becomes unusable on Windows 11 with UHD monitors, although hosted-plugin use still worked.checked 15 Oct 2026
The company
- Maker identity
- The official Helm manual identifies Matt Tytel as the developer.checked 15 Oct 2026
- Maker location
- Matt Tytel describes himself as a software synthesizer developer in the Boston area.checked 15 Oct 2026
Alternatives to Helm
- 1
DefleMask
Free planAndroidiOSLinuxmacOS8.1$6.99 one-time - 2
Vital
Free planOpen sourceLinuxmacOSSelf-hostedWindows8.0From $5 a month - 3
SynthMaster 3
Free planiOSmacOSWindows7.7$99 one-time - 4
Dexed
Free planOpen sourceiOSLinuxmacOSWindows7.6Free plan - 5
Cardinal
Free planOpen sourceWebAPILinuxmacOS7.5Free plan - 6
Surge XT
Free planOpen sourceLinuxmacOSWindows7.2Free plan