β-Modulated Brown Noise
Quiet your surroundings, hold your attention.
I created this tool after spending time with patients and students who struggle to concentrate in noisy or unpredictable environments. It generates scientifically informed background noise — specifically, brown noise with optional beta-frequency amplitude modulation — directly in your browser. Nothing is streamed, stored, or sent anywhere. No data is collected. It works on any device with a modern browser and costs nothing to use.
Use cases
The evidence base is most consistent for tasks involving reading, verbal working memory, and sustained attention — the kind of work that revision and study typically involve. Below is a practical guide to when this tool is likely to help and when it may not.
- Exam revision and note-taking
- Reading dense material
- Writing and editing
- Sustained desk work in noisy environments
- Pre-task priming (settling in before starting)
- Blocking out open-plan office chatter
- Novel or highly demanding cognitive tasks
- Creative tasks requiring free association
- Tasks fully consuming working memory
- If you find any background sound distracting
- Listening tasks (try headphones and zero volume from surroundings)
Getting started
This tool is not meant to be listened to actively. Within a minute or two of starting it, it should fade into the background and stop registering consciously. If it remains noticeable, that is almost always a sign the volume is too high.
The noise masking works best when the sound field is consistent and close. Over-ear headphones are ideal; earbuds work well too. Using speakers mixes the noise with the room environment and loses much of the masking benefit.
The noise will feel present and slightly prominent at first. Your auditory cortex habituates quickly. Give it a full minute before deciding it is too loud — it will recede on its own.
You want just enough noise to make surrounding conversations indistinct. That is the point at which it is working. Going louder provides no additional benefit and the research suggests it starts to impair performance above a certain threshold.
The modulation rate (16 Hz) and depth (9%) are set at values that reflect current research and are intentionally subtle. You should barely be able to tell the noise has any oscillation to it. If you want pure brown noise without entrainment, set the depth to zero.
The noise colour slider is new. Most people will find brown (the default) or slightly darker most comfortable for extended sessions. Lighter colours (pink, red) can feel more stimulating but also more noticeable — some people find them easier to tune out, others find them distracting. Experiment briefly at the start of a session, then leave it alone.
Why noise helps
Auditory masking
The most straightforward mechanism is masking. Background conversations and unpredictable sounds are particularly disruptive to sustained attention because the auditory system has a reflexive orienting response to novel sounds — something evolutionarily useful but not helpful when you are trying to hold a complex idea in working memory. Broadband noise raises the auditory threshold so that lower-level irregular sounds become inaudible, removing the trigger for the orienting response.3,4
The masking benefit is strongest for unpredictable environmental sounds — speech fragments, doors, passing vehicles. It is not a silence substitute; quiet environments without unpredictable sounds are typically better still. The tool is designed for situations where quiet is not available.
Noise colour and spectrum
Different noise colours have different spectral energy distributions. White noise has equal energy at all frequencies. Pink noise (−3 dB per octave) has more energy in the bass, matching the roughly logarithmic sensitivity of the auditory system — many people find it less harsh than white. Brown or red noise (−6 dB per octave) rolls off more steeply, giving a deeper, warmer rumble that many people find easiest to habituate to over long periods. At the dark extreme, black noise (−9 dB per octave) concentrates energy in the very low frequencies, more felt than heard — some find it calming, others find it unsettling.2
The research on which colour is best for cognition does not show a clear winner. A 2024 study found both white and pink noise helpful for children with attention difficulties, without a significant difference between them.2 The choice is largely personal preference. Brown noise is the default here because it is the colour most people spontaneously describe as comfortable for long sessions.
Beta entrainment
The optional modulation component is based on research into neural entrainment. The amplitude of the noise is modulated at a rate in the beta frequency band (12–20 Hz). The hypothesis — supported by some experimental evidence — is that periodic auditory stimulation can bias the brain toward oscillatory patterns at the same frequency, and that beta-band activity is associated with sustained, focused attention states.1
A 2024 study found that rapid amplitude modulation in music improved performance on attention tasks in listeners with attentional difficulties, with effects linked to increased beta-band neural entrainment.1 This tool applies a similar modulation to broadband noise rather than music, which is an extrapolation from the original design but a reasonable one.
The modulation depth is set to 9% by default — at the edge of conscious perception. This is intentional. The aim is to provide a regular periodic signal without the modulation becoming a foreground rhythm that competes with the task.
When it is useful
The evidence base is most consistent for tasks involving reading, verbal working memory, and sustained attention — the kind of work that revision and study typically involve. Effects on creative tasks are more variable. Some research suggests music with lyrics impairs verbal tasks even at low volumes, and that background sound of any kind can hinder highly demanding or novel tasks that fully consume working memory.5,6,7
Revision is a particularly good fit. It is overwhelmingly a sustained-attention task: staying with the material, resisting distraction, returning attention when it wanders. The masking component helps with the environmental side of that; the entrainment component may help with the attentional side. Neither claim is extravagant.
There is also some evidence for benefit during pre-task priming — putting this on while you settle at your desk and organise yourself before beginning work. The transition into focused work is itself a cognitive task that benefits from low distraction.
What we do not know
This tool is a synthesis of current published research applied to a practical design, not a validated therapy. The brown noise masking component and the beta amplitude modulation component have each been studied in separate research programmes. Their combination in this exact form has not been tested in a controlled trial, and we cannot claim the combined effect is greater than either component alone, or that it produces any specific outcome for any specific person.
The research on noise and cognition consistently shows that effects vary considerably between individuals. Some people find any background sound distracting regardless of its properties. If this tool makes concentration harder rather than easier, that is genuinely useful information about how your brain works — not a failure of the tool. Try setting the depth to zero for pure noise, or try silence.
The original amplitude modulation research used music as the carrier, not noise. This is a reasonable extrapolation but not a tested one. The 9% default depth is set deliberately low to minimise any risk that the oscillation itself becomes distracting.
This tool does not diagnose, treat, or manage any medical or neurological condition. If you have significant and persistent difficulties with attention that affect daily life, that is worth discussing with a doctor.
Get in Touch
If you would like to discuss sleep difficulties, or think you may have a condition such as obstructive sleep apnoea that is affecting your ability to concentrate and function during the day, please do get in touch.
Private secretary: 0207 458 4584
Email: secretary@consultant-surgeon.co.uk