EqualAPO Equalizer Overview
Equalizer APO is a free, open-source system-wide parametric equalizer for Windows that applies equalization and other audio processing to your entire system output (or specific devices). Implemented as an Audio Processing Object that hooks into the Windows audio pipeline, it can adjust frequency response with unlimited filters, apply effects, and even do convolution (for room correction or headphone correction with impulse responses), all configured through text-based or graphical configuration. It is lightweight and runs with very low latency. It is popular with audio enthusiasts who want precise control over their sound, often paired with the graphical Peace interface. The complete installer means EqualAPO Equalizer sets up without fetching anything online during installation. The link on this page goes to Sourceforge's official EqualAPO Equalizer download.