Frequency is how many times a sound wave vibrates per second, measured in hertz (Hz). Concert pitch puts the A above middle C at 440 Hz, the international standard. Some musicians prefer A = 432 Hz; it is about 32 cents (a third of a half step) lower. Neither is proven better; it is a matter of taste. This studio lets you switch and hear the difference.

These tones were popularized in the late twentieth century and are widely shared online with claims about healing. There is no strong scientific evidence for those claims. Here they are treated as musical colors: the table shows the nearest note and how far off it is, so you can hear how each tone sits against the music.

Play a slightly different tone in each ear (for example 200 Hz left and 210 Hz right) and your brain perceives a gentle 10 Hz beat. They only work with headphones. Research is mixed: some studies report small reductions in anxiety, others find little effect. Use them as a relaxation aid, not a treatment.

• Delta, 0.5 to 4 Hz: deep sleep.
• Theta, 4 to 8 Hz: drowsy, meditative states.
• Alpha, 8 to 13 Hz: relaxed but awake.
• Beta, 13 to 30 Hz: alert, focused.
• Gamma, above 30 Hz: high-level processing.

Beat settings in the signal stack are named for these bands.

Isochronic tones pulse one tone on and off at a steady rate and work without headphones. Rain and ocean layers are filtered noise that masks distractions; many people find steady natural sound calming, and it can help cover mild ringing in the ears.

Slow tempos near 60 to 70 beats per minute, predictable harmony, soft attacks and moderate volume are the most reliable musical ingredients for relaxation. Pair them with slow breathing. Speed up for focus or a workout; slow down for rack time.

• Extended chords: 9ths, 11ths and 13ths add color tones above the basic triad.
• Rootless voicings: the keys leave the root to the bass, so chords float.
• Voice leading: each chord moves to the nearest notes of the next one, so the harmony glides.
• The lift: raising the key a half or whole step for the final hook, a classic gospel move.
• Runs: quick pentatonic fills at the end of a phrase.

Tinnitus and hearing loss are among the most common service-connected conditions for veterans. Keep volume moderate (a common guide is no more than 60% volume for 60 minutes at a time), take breaks, and lower the signal layers if they feel sharp.