The 7.1 buttons on HyperX headsets are used to enable 7.1 surround sound. This feature allows you to hear sounds from all around you, giving you a more immersive gaming experience. To use this feature, you need to connect the headset to a computer with a sound card with 7.1 surround sound support. You can then enable the 7.1 surround sound feature in the software that came with your sound card.