Frequencies, sound waves & your brain

Frequency is measured in hertz (Hz), the number of vibrations each second. A low drum note has a low frequency. A whistle has a high one.

Loudness is measured in decibels (dB). Sounds at or below 70 dB are unlikely to harm hearing. Long or repeated time at 85 dB or more can cause hearing loss.

Music switches on brain areas for hearing, emotion, memory and movement at the same time. That is why the right sound can calm you or lift you.

A 2019 review of 22 studies found a medium overall effect of binaural beats on memory, attention, anxiety and pain. Listening before a task seemed to work better than only during it.

An earlier review found that lower anxiety was the most consistent result across studies.

Reviewers describe most results as limited or contradictory, and many effects as weak and short-lived. Results seem to depend on the tones used, how long people listen, their age and their attention.

Apps often say beats will push your brain into a “theta” or “alpha” state. A 2023 review of 14 brain-wave studies found 5 supported that idea, 8 contradicted it, and 1 was mixed.

• Keep the volume low. Loudness, not the beat, is the risk
• Notice how you actually feel, not what the label promises
• Stop if you feel dizzy, uneasy or get a headache
• Compare with calm music or silence. Use whatever works best

Most modern music is tuned so the note A is 440 Hz. Some people prefer music retuned to 432 Hz, which sounds very slightly lower.

In one pilot study, 12 people with spinal cord injuries listened to their favorite music tuned each way. Sleep scores improved with 432 Hz but not with 440 Hz. Stress didn’t change much with either. The authors said bigger, better studies are needed.

Claims that one tone repairs DNA, heals organs or raises your “vibration” are not backed by good-quality studies in people. A pure tone at any frequency is still just a sound.

Health experts warn that personal stories are often presented as evidence. Stories can be sincere and still not prove that something works.

Most “frequency” tracks are slow, soft and soothing, and people often listen while resting. Calm music and relaxation can lower stress on their own, whatever the tuning.

White noise contains all the frequencies people can hear in equal amounts. It sounds like static from an untuned radio or a fan.

Pink noise has stronger low frequencies, so it sounds deeper than white noise. Think of rain or a waterfall.

Brown noise cuts the high frequencies even more than pink noise. It sounds grainier or rougher, like ocean waves crashing.

Brown noise is popular online, but it has the least research of the three.

A 2021 review of 38 studies looked at steady noise and sleep. Some studies found it helped, others found it disturbed sleep. The quality of the evidence was very low, and the authors said more research is needed before noise is promoted as a sleep aid.

Pink noise has shown some promise for deeper sleep in older adults, but mostly in lab studies where researchers timed the sound during the night.

• Put it across the room, not next to your head
• Keep it no louder than a quiet background conversation
• Turn it on just before bed
• Use a timer so it plays while you fall asleep, not all night

A sleep doctor warns that white noise may interrupt important stages of sleep, and that it can affect hearing if it’s too loud. More research is needed on the best volume and length for pink and brown noise.

Some studies in children found white noise may slow heart and breathing rates. Young ears are delicate, so keep any machine low and well away from where a child sleeps.

A 2024 review pooled 13 studies of children and young adults with ADHD or attention problems. White or pink noise gave a small but real benefit on attention tasks in the lab.

In the same review, people without attention problems did slightly worse with white or pink noise. So noise isn’t a one-size-fits-all focus trick.

1. Pick one task you do often, like reading or homework
2. Do it some days with soft noise and some days in quiet
3. Rate your focus each time from 0 to 10
4. Keep the setup that works for you

Tabletop or phone sound generators are often used to help with relaxation or sleep. Wearable ones fit in the ear like hearing aids and can give relief through the day.

Cognitive behavioral therapy (CBT) helps you notice upsetting thoughts about tinnitus and change how you respond, so it has less impact on your life.

If your ears ring after loud noise, or sounds seem muffled, get your hearing checked. An audiologist or your clinical provider can help.

• “Cures,” “heals,” “repairs DNA” or “detox”
• “Ancient secret” or “what doctors don’t want you to know”
• Brain-wave claims with no studies linked
• Lots of reviews and stories, but no research
• Pressure to buy a premium track or device

• Says “may help you relax,” not “will fix you”
• Links to real studies and admits their limits
• Encourages safe volume and breaks
• Says it works alongside care, not instead of it

• Who made this claim, and do they sell the product?
• Was it tested in people, or only in theory?
• How many people, and was there a comparison group?
• Did anyone else get the same result?