A number of the frequencies outlined can be found from the BetterSleep app to mix with other sounds or content. The A4 at 440 Hz is highlighted to the chart. For more geeking out, you might have an interest With this interactive comparison of equal temperament vs just intonation https://codyrhwnb.blog2freedom.com/32065580/detailed-notes-on-fréquence-396-hz-bienfaits