Isochronic Tones feature short bursts of alternating sine waves and silence. The following MP3 files. 136.1 Hz & 18.5 Hz sine wave, can be downloaded for free.
The two Isochronic Tone files have different frequencies: one uses 18.5 Hz (Audio and Visual Entrainment) and the other 136.1 Hz. Both use a .05 second interval. Sine wave for .05 seconds followed by .05 seconds of silence, repeated.
Download free isochronic tones
Each MP3 file is 10 minutes long and mono. You can listen to them with or without headphones. They aren’t the prettiest sounding files I’ve ever made but headphones are probably more effective. I must confess I don’t use them myself and therefore have no experience with them. No claims are made.