Equalizer APO - A system-wide equalizer for Windows 7 / 8 / 8.1 / 10 with channel remapping/copying capabilities
PulseEffects - Limiter, compressor, reverberation, stereo equalizer and auto volume effects for Pulseaudio...
DFX Audio Enhancer - Formerly known as DFX Audio Enhancer, FxSound Enhancer instantly boosts the sound quality of the music on your PC.
JamesDSP for Linux - An audio effect processor for PipeWire and PulseAudio clients.
FxSound - Clearer Sound for Your PC. The new FxSound boosts your sound quality, volume, clarity and bass.
Equalizer Pie - Equalizer Pie is a free audio manipulation application for OS X.