In the 1980s every piece of audio equipment had to have a graphic equalizer. It must’ve been the law or something. Modern Macs offer a graphic equalizer in certain apps, but not systemwide – or not until now, that is.
eqMac is a free app that provides a systemwide graphic equalizer that affects audio playback in all apps that output sound, regardless of what they are.
Once installed it adds an icon to the menu bar that you click to adjust the traditional sliders up and down. The pencil icon can be clicked to write the current settings as a new default, for quick selection later.
And that’s about all there is to say about what is a very simple but useful app. If you find there are any audio glitches while using it, hit the reset icon to the left of the sliders. To uninstall it, use the special uninstaller supplied within the installation DMG file.