If you landed on this article looking for a mythical "NVIDIA High Definition Audio Equalizer" tab in your settings, let this be your closure:

Best for advanced users and streamers. It acts as a virtual mixer, allowing you to route NVIDIA audio through various EQ bands and compression settings before it goes to your hardware.

This is widely considered the gold standard for Windows users. It is a powerful, low-latency parametric equalizer that can be applied specifically to the NVIDIA High Definition Audio device. The Peace Extension provides a user-friendly interface with presets and sliders.