The core Schumann resonance frequency, such as 7.83 Hz, is an extremely low-frequency electromagnetic field—below the range of human hearing. Its influence is subtle and cumulative, working through environmental modulation rather than audible sound.Therefore, the device itself is designed to operate quietly or silently when emitting the pure frequency. If you use the included headphones, you will be able to hear the associated audio output. To help you get the most out of the device, we recommend placing it near your resting area. It maybe have positive changes over time, such as improved sleep quality or a greater sense of relaxation, rather than immediate noticeable effects