OSL Side Effects



Mid/Side processing and stereo widening

OSL Side Effects is a versatile audio plugin that allows the stereo field to be manipulated in both subtle and creative ways.

It separates a stereo signal into Mid and Side channels which can be independently equalised, compressed, saturated, boosted, attenuated and panned using an intuitive processing chain. This makes it possible to alter the width of a mix in ways that would be impossible using conventional stereo processing techniques.


  • 4 band Mid/Side EQ with interactive graph
  • FFT spectrum analyser
  • Mid/Side compressor with transfer curve graph
  • Gain reduction meters
  • Tape-style saturation
  • Mid/Side stereo panning
  • Input and output gain controls
  • Stereo visualiser (goniometer)
  • Phase meter
  • Mid/Side and Left/Right output meters
  • Left/Right mode
  • Oversampling up to 16x
  • Preset system including 17 factory presets
  • All parameters can be automated from the host DAW
  • Light on CPU


Try OSL Side Effects for free. Until the plugin is registered it will output a short silence every 45 seconds.


v1.1.3 – 2023-06-05

  • Fixed: Memory leak.

v1.1.2 – 2020-12-01

  • Added: macOS 11 (Big Sur) and mac Silicon M1 compatibility.

v1.1.1 – 2020-09-18

  • Changed: Gain and pan rotary knobs are now bi-directional.
  • Fixed: “%L” suffix is correctly recognised when manually entering pan knobs values.

v1.1.0 – 2020-09-16

  • Added: Left/Right mode.
  • Changed: Channel linking state is remembered when GUI loses/gains focus.
  • Changed: Restored brighter tab button colours.
  • Fixed: Bypassed channels no longer output audio while the opposite channel is soloed.

v1.0.1 – 2020-07-13

  • Changed: Support ADSRsounds.com license key format.

v1.0.0 – 2020-06-19

  • Initial release.



Windows 8–11
Plugin formats: 64-bit VST3

OS X 10.11–macOS 13
Plugin formats: 64-bit VST3/AU (Arm64/M1 native)

VST3 logoAudio Units logo

VST3 is a registered trademark of Steinberg, LLC. AU and Audio Units are registered trademarks of Apple Computers, Inc.


“A perfect starting point in your stereo field mangling adventures.”

Synth Anatomy

“A channel strip plugin that lets you apply each of its processes independently to the mid and side components of your stereo signals (or just the left and right, if you prefer), with plenty of metering and visualisations.”

Computer Music magazine, December 2020