Free Audio Effect Plugins

A surprisingly complete free effects toolbox in 2024-26 — many of these are better than their paid equivalents. Pair with synths-free-oss for a fully free production rig. For format compatibility see audio-plugin-formats.

Free effect bundles (start here)

• ★ MeldaProduction MFreeFXBundle — closed source freeware; 40+ plugins (EQ, comp, dynamics, reverb, distortion, utilities). Cross-platform VST3 / AU / CLAP. The single most-downloaded free bundle.
• ★ Calf Plugins — GPL LV2 / LADSPA plugin suite; Linux. Reverb, comp, EQ, vocoder, sidechain — the default effects pack on Linux audio rigs.
• ★ x42 plugins (Robin Gareus) — GPL LV2 / VST. Mixers, meters, EQs aimed at pro broadcast / Linux audio. Includes EBU R128 loudness meter.
• ★ ChowDSP plugins — BSD / GPL; cross-platform VST3 / AU / CLAP / LV2. Tape, distortion, chorus, modulators. The new-wave OSS effect pack of 2024-26.
• Tokyo Dawn Labs (TDR) — free + paid lineup; free plugins are excellent (Nova, Kotelnikov, Proximity, SlickEQ).
• Voxengo Free — free closed-source set: SPAN, Marvel GEQ, TubeAmp, OldSkoolVerb.
• Klanghelm — free closed-source: IVGI saturation, DC1A compressor, MJUC jr. compressor.
• Airwindows — MIT-licensed; ★ 400+ plugins by Chris Johnson, all free, all named after silly things; surprisingly great sound.

EQ

• ★ TDR Nova — free dynamic EQ; the best free dynamic EQ.
• MEqualizer (Melda) — free parametric.
• Voxengo Marvel GEQ — free 16-band graphic EQ.
• TDR SlickEQ — free vintage-style.
• x42 fil4 — free LV2 / VST parametric EQ for Linux.

Compression

• ★ TDR Kotelnikov — free mastering bus compressor.
• Klanghelm DC1A — free general-purpose compressor; punchy.
• Klanghelm MJUC jr. — free vari-mu emulation.
• Pressure (Airwindows) — small, character-y.
• MCompressor (Melda) — free flexible compressor.

Reverb

• ★ Valhalla Supermassive — free closed-source; massive cinematic reverbs / delays. Cross-platform. Iconic sound.
• Old Skool Verb (Voxengo) — free clean reverb.
• DragonflyReverb — GPL cross-platform; multiple algorithms (Room, Hall, Plate, Early Reflections). Native CLAP support.
• x42 zita-rev1 — Linux LV2 port of Fons Adriaensen's Zita reverb.
• MConvolutionEZ (Melda) — free convolution / IR loader.
• TAL-Reverb-4 — free closed.

Saturation / character / distortion

• ★ Klanghelm IVGI — free saturator; iconic warmth.
• CHOW Tape Model — free tape saturation.
• BlackBox HG-2 trial / free taste — analog summing.
• Airwindows Console family — virtual analog summing.
• ChowDSP BYOD — see neural-amp-modeling; free pedalboard.

Modulation / FX

• MFlanger / MChorusMB / MPhaser (Melda) — free modulators.
• TAL-Chorus-LX — free Juno chorus emulation.
• ChowDSP Chow Phaser / Chow Flanger — free, cross-platform.
• Airwindows Tremolo / Vibrato — small character plugins.

Mastering / metering / analysis

• ★ Voxengo SPAN — free spectrum analyzer; the de-facto free metering plugin.
• ★ Youlean Loudness Meter 2 — free closed-source LUFS / EBU R128 meter; broadcast-grade. Pro version paid.
• TT Dynamic Range Meter — free DR meter.
• iZotope Insight 2 — paid; broadcast-standard metering suite.
• MLoudnessAnalyzer (Melda) — free LUFS / true peak.

Mid/side / stereo / utilities

• MUtility (Melda) — free routing / M-S / phase / gain.
• bx_solo (Brainworx) — free M/S monitoring.
• Voxengo Stereo Touch — free stereo widening.
• Airwindows MoNoam / Mono — mono utilities.

Restoration / cleanup

• See vocal-stem-separation and podcast-voice-tools for audio repair / noise reduction.
• Voxengo Redunoise — paid.
• Audacity Noise Reduction — built into Audacity.

Pick this if…

• One bundle to start: MeldaProduction MFreeFXBundle.
• Free reverb that punches above its price: Valhalla Supermassive.
• Free dynamic EQ: TDR Nova.
• Free mastering compressor: TDR Kotelnikov.
• Free spectrum analyzer: Voxengo SPAN.
• Free loudness meter: Youlean Loudness Meter 2.
• Linux LV2 effects: Calf + x42 + ChowDSP.
• Tape / character / saturation: ChowDSP CHOW Tape Model + Klanghelm IVGI.