Sounds like hype: there's scant evidence the 'binaural beats' illusion relaxes your brain

Specific frequencies are thought to be involved in specific cognitive tasks.

• During deep sleep, the predominant brain activity occurs with frequencies between 1 and 4 Hertz (delta waves.) Delta waves are associated with learning and motivation.
• Theta waves (4-7Hz) are linked to memory and emotional regulation.

Brain entrainment - where brain cells fire at the same frequency - is a real effect that happens in response to particular rhythmic frequencies perceived by our senses. A deep-pitched musical tone can cause your brain cells to start firing at the same frequency.

• The authors played binaural or monaural (normal) beats to 16 participants, and recorded their brain activity with EEG.
• They found both beats can entrain the brain to their particular frequency, but participants described no significant effect on their mood changes.
• However, binaural beats can generate "cross-frequency connectivity," where the brain coordinates its activity across different types of brain waves.
• It's then possible that binaural beats can be beneficial to some types of cognition, including memory recall.
• An analysis of 35 studies demonstrated a modest effect on attention, memory, anxiety, and pain perception. However, these were not tested in the current study.