"Equalizer presets" refer to pre-set configurations or settings on an audio device that adjust the balance of different frequency ranges in the sound to achieve a desired sound quality or effect. Full definition
The phone doesn't support high - resolution audio like the Axon 7, but with wired headphones you do get a built - in audio tuner that provides fine balance controls with equalizer presets for different genres of music and enhancements for certain headphones like the OnePlus Bullets or JBL E1 +. (pcmag.com)
Clicking the dial opens up the menu system, which lets you adjust audio settings like game / voice chat mix, choose equalizer presets (or make your own custom EQ setting with a five - band equalizer), toggle simulated surround sound, or change the source between PC (USB - only), PS4 (USB for voice chat, optical for game audio), and anything connected to the transmitter through the 3.5 mm input. (pcmag.com)
Equalizer presets offer Rock, Pop, and Jazz, among others, while sound field settings add a bit of echo, an unusual effect for a car system. (cnet.com)