Equalizer APO (Audio Processing Object) is widely considered the most powerful audio tool available for Windows. However, its interface—a blank text file—intimidates many users. The "plugins" you refer to are not standalone installable files in the traditional VST sense (though VSTs are possible), but rather that sit on top of Equalizer APO to extend its functionality.
: While not a plugin itself, it provides thousands of pre-made EQ profiles for specific headphone models that can be imported directly into Equalizer APO. VST Plugin Support equalizer apo plugins
Equalizer APO supports plugins, which allow you to add advanced professional audio effects to your entire system's output. AutoEQ Project : While not a plugin itself,
If you are building a high-end audio processing chain on Windows, your "plugin stack" will look like this: equalizer apo plugins