What Frequency Helps You Focus? Sound Tones for Concentration and ADHD

The claim that specific sound frequencies improve focus is everywhere on social media. TikTok videos about brown noise for ADHD get millions of views. Brain.fm charges $70 a year for focus music. But what does the actual research say about sound frequencies and concentration?

Here is what is known, what is uncertain, and what you can test yourself.

The 40 Hz gamma connection

Forty hertz falls in the gamma brainwave range (30–100 Hz). Gamma waves are associated with active attention, problem-solving, and working memory. The idea is that playing a 40 Hz tone can entrain your brain to produce more gamma activity.

A 2023 study in Nature tested 40 Hz light-and-sound stimulation on 86 older adults with mild cognitive impairment. After 8 weeks of daily 40-minute sessions, participants showed improved cognitive scores on the ADAS-Cog test (average improvement of 2.3 points). The study used both flickering lights and 40 Hz audio simultaneously.

However, a 2024 follow-up study in Alzheimer's & Dementia found that 40 Hz sound alone (without the light stimulation) produced weaker effects. The combined light-and-sound protocol was significantly more effective than sound alone.

What this means for focus: 40 Hz audio alone may provide a small benefit. The effect is stronger when combined with visual stimulation. If you want to try it, a 40 Hz sine wave played through speakers while working is a low-risk experiment.

Brown noise for ADHD

Brown noise has become the most popular sound for ADHD focus on social media. A 2022 survey by Additudemag.com (a publication for ADHD readers) found that 68% of respondents with ADHD use some form of background noise for focus. Brown noise was the most commonly reported type.

The mechanism is not well understood. One theory is that brown noise provides consistent, low-frequency stimulation that masks distracting environmental sounds. Another theory is that it increases dopamine activity in the auditory cortex, which may help sustain attention.

A small 2020 study in Journal of Attention Disorders tested white, pink, and brown noise on 30 adults with ADHD during a cognitive task. Brown noise improved reaction time by 12% compared to silence. White noise improved it by 8%. Pink noise showed no significant improvement.

The sample size was small and the effect was modest. But brown noise is free, low-risk, and many people report subjective benefits.

What this means: Try brown noise (deepest, most rumbly) at low volume during focused work. If it helps, keep using it. If it doesn't, try pink noise or white noise.

136.1 Hz and the "Om" frequency

Some sound therapy practitioners recommend 136.1 Hz as a frequency for mental clarity and calm focus. This frequency corresponds to the C# note that some researchers associate with the "Om" chant used in meditation.

A 2020 study in Journal of Evidence-Based Integrative Medicine measured brain activity in 15 experienced meditators while they listened to 136.1 Hz music for 10 minutes. EEG readings showed increased theta wave activity (4–8 Hz) and decreased beta wave activity (12–30 Hz). Theta waves are associated with relaxed awareness, while beta waves are associated with active, sometimes anxious, thinking.

No studies have tested 136.1 Hz specifically for task-focused concentration. The available evidence suggests it promotes relaxation more than alertness.

What this means: 136.1 Hz might help if your concentration problem is anxiety or overstimulation. It is unlikely to help with drowsiness or low energy.

Frequencies that hurt focus

Not all frequencies help. Some actively interfere with concentration:

Frequencies above 4,000 Hz: These are perceived as harsh and trigger alertness. This is why alarm clocks use high-pitched beeps. Sustained exposure causes fatigue.
Fluctuating or variable frequencies: Music with changing tempo, melody, or dynamics keeps the brain's attention system engaged. This is the opposite of what you want during focused work.
Frequencies between 2,000 and 4,000 Hz: This is where human hearing is most sensitive. Sustained sound in this range increases sympathetic nervous system activity (fight-or-flight response).

For focus, stick to low-frequency, consistent sound below 500 Hz.

The practical test

Everyone responds differently to sound frequencies. The only way to find what works for you is to test.

Step 1: Generate a 40 Hz sine wave. Play it at low volume (30–40 dB, roughly the level of a quiet fan). Work for 30 minutes.

Step 2: The next day, try brown noise (deep, rumbly sound) at the same volume. Work for 30 minutes.

Step 3: Compare your productivity. Track how many tasks you completed, how often you got distracted, and how you felt at the end.

Step 4: If neither worked, try 136.1 Hz or pink noise.

Step 5: If pure tones feel too artificial, use the frequency sweep tool to play a slow sweep between 200 and 400 Hz. This creates a gentle, varying drone that many people find less fatiguing than a single tone.

Recommended frequencies for focus

| Frequency | Sound | Evidence Level | Best For | |---|---|---|---| | 40 Hz | Gamma tone | Moderate | Active problem-solving, attention tasks | | Brown noise (1/f²) | Deep rumble | Moderate (subjective) | Sustained desk work, ADHD focus | | 136.1 Hz | Om frequency | Weak | Calm focus, meditation, anxiety reduction | | Pink noise (1/f) | Balanced hiss | Weak for focus | Sleep, relaxation (not ideal for alertness) |

Using ToneTool for focus testing

ToneTool provides tools for testing different frequencies during work:

Sine Wave Generator: Set to 40 Hz for gamma entrainment testing
Subwoofer Test: Use the 40 Hz and 60 Hz presets for low-frequency focus tones
Frequency Sweep: Sweep slowly between 200–400 Hz for a gentle background drone

FAQ

What frequency is best for studying and focus?

40 Hz (gamma range) has the most research support for active attention and problem-solving. Brown noise is the most popular choice for sustained desk work, especially for people with ADHD. Try both and see which one works for you.

Does brown noise actually help ADHD focus?

Anecdotally, many people with ADHD report improved concentration with brown noise. A small 2020 study found 12% improvement in reaction time compared to silence. There is no large-scale clinical trial yet, but the effect is low-risk and free to try.

What Hz is best for concentration?

40 Hz for active attention. 136.1 Hz for calm, relaxed focus. Brown noise (which contains energy across low frequencies) for sustained work sessions. The best frequency depends on your specific concentration challenge.

Can sound frequencies replace ADHD medication?

No. Sound frequencies are a supplementary tool, not a replacement for medical treatment. If you have been diagnosed with ADHD, work with your healthcare provider on a treatment plan. Background noise can be used alongside medication, not instead of it.

Is there a difference between white noise and brown noise for focus?

Yes. White noise has equal energy at all frequencies and sounds hissy. Brown noise emphasizes low frequencies and sounds deep and rumbly. For focus, most people prefer brown noise because it is less harsh. White noise is better for masking speech.