You can make white noise using a household fan, a free app on your phone, or audio software on your computer. White noise is simply a blend of all audible frequencies playing at equal energy levels, producing a steady “hiss” that masks other sounds. The method you choose depends on whether you want a quick ambient solution or a custom audio file you can control precisely.
Why White Noise Works
White noise reduces your awareness of disruptive sounds by shrinking the gap between background noise and sudden peaks like a door slamming or a car horn. A study in Frontiers in Neurology found that broadband sound reduced the time it took healthy adults to fall asleep by 38%, dropping from 19 minutes to 13 minutes in an experimental insomnia model. The effect isn’t about drowning out noise with louder noise. Your brain actively processes recognizable patterns like speech and ignores sounds it can’t identify as patterns, like static. White noise exploits that tendency: it fills the audible spectrum with a flat, patternless signal so that sharp, patterned noises (a conversation next door, a barking dog) become harder for your brain to pick out.
Use What You Already Have
The simplest white noise source is a fan. Any fan pushes air through blades at varying speeds, creating turbulence that produces a broad spread of frequencies. A box fan or pedestal fan pointed away from you (so you’re not blasted with air) works well. Air purifiers, bathroom exhaust fans, and even a running shower produce a similar broadband hiss.
A radio or TV tuned to an empty channel produces static that’s close to true white noise, though this method is harder to find now that most broadcasts are digital. A dehumidifier or portable heater with a fan element also creates steady background sound, though these tend to emphasize lower frequencies and sound more like a rumble than a hiss.
Dedicated Sound Machines
Mechanical (fan-based) sound machines use a small internal fan and an adjustable housing to shape the tone. Rotating the housing changes the size of the opening, which shifts the pitch and volume. These produce real air movement, so the sound has a natural, non-looping quality that many people prefer over digital playback.
Electronic sound machines use speakers to play pre-recorded or synthesized loops. They’re smaller, quieter, and offer more variety (rain, ocean, pure static), but cheaper models sometimes have audible loop points where the track restarts. If that bothers you, look for machines or apps that advertise long or seamless loops.
Free Apps for Your Phone
Several well-reviewed apps generate white noise without requiring a purchase. Here’s what to look for and what the main options offer:
- White Noise Lite: Comes with preset mixes (fire, water, wind layered together) and lets you create your own by stacking sounds. You can also record real-world sounds and add them to your playlist. Timers let you set the sound to fade or stop after a set duration, and playback continues in the background while you use other apps. The loops are fairly short, which can be noticeable on some tracks.
- Sleep Sounds by Sleep Pillow: Tap a sound and it plays until you stop it, or set a timer from one minute to 75 minutes. The free version lets you mix up to three sounds with individual volume sliders and save one custom mix. Rain and ocean tracks loop seamlessly enough that the restart point is hard to detect.
- White Noise Deep Sleep Sounds: A good selection of free sounds with the ability to mix two together and set an unlimited timer. The paid upgrade adds 60 extra sounds and an extra-long fade-out of up to an hour, which is useful for falling asleep gradually. Some free sounds loop noticeably every ten seconds or so.
- Headspace: Primarily a meditation app, but its “Soundscapes” section offers 45-minute ambient recordings captured in 3D audio. The sound rises and falls naturally rather than playing on a flat loop, which makes it feel more immersive. You can’t layer your own mixes, though.
For any app, make sure it can keep playing when your screen locks or when you switch to another app. All of the options above support background playback.
Create a Custom File in Audacity
If you want a white noise track at an exact length and volume, the free audio editor Audacity can generate one in seconds. Open Audacity, go to Generate > Noise, and select “White” as the noise type. Set the amplitude between 0 and 1 (the default of 0.8 is a good starting point, where 1.0 is the maximum volume before distortion). Type in your desired duration, click “Generate,” and you’ll have a white noise clip you can export as an MP3 or WAV file.
Audacity also generates pink noise and brown noise from the same menu. Pink noise rolls off energy at higher frequencies, so it sounds deeper and softer, like steady rainfall. Brown noise drops off even more steeply, producing a low rumble similar to thunder or a waterfall. If pure white noise sounds too harsh or “hissy” to you, try pink or brown instead.
Once you have your file, you can loop it in any media player. A 10-minute track set to repeat will play all night. If you want to avoid even the perception of a loop, generate a longer file (30 to 60 minutes). Because white noise is random by nature, there’s no repeating pattern for your ear to latch onto, so even short loops tend to sound seamless.
Write Your Own With Code
If you’re comfortable with basic programming, generating white noise is surprisingly simple. White noise is just a sequence of random numbers. In Python, you can create a one-second clip with two lines of core logic using the NumPy library: generate an array of random values between -1 and 1 using np.random.uniform(-1, 1, sample_rate), where sample_rate is typically 44100 (CD-quality audio). Write that array to a WAV file, and you have white noise.
For Gaussian white noise (where the random values cluster around zero in a bell curve rather than being evenly spread), use np.random.normal(0, 1, sample_rate) instead. Both sound like white noise to your ears. The difference is subtle: uniform distribution produces a slightly “harder” static, while Gaussian distribution sounds marginally smoother. Either works for sleep or focus.
White, Pink, or Brown: Picking the Right Color
White noise contains all audible frequencies at equal energy. This makes it the most effective type for masking a wide range of sounds, from low bass through high-pitched tones. It sounds like TV static or a hissing radiator.
Pink noise reduces energy as frequency increases, so it sounds warmer and less sharp. Think of wind through trees or steady rain on pavement. Many people who find white noise grating prefer pink noise for sleep.
Brown noise (sometimes called red noise) drops off even more at higher frequencies. It’s the deepest of the three: a low, rumbling drone like heavy surf or distant thunder. It’s popular for concentration and for masking low-frequency sounds like traffic or HVAC hum.
There’s no single best color. If you’re trying to block out voices (which sit in the mid-to-high frequency range), white noise is the strongest mask. If high-frequency hiss bothers you, move toward pink or brown.
Volume and Safety
Keeping the volume at a safe level matters more than most people realize, especially for overnight use. Testing has shown that commercially available white noise machines can exceed 91 decibels on their maximum setting, which is above occupational safety thresholds even for a two-hour exposure. Many machines can produce moderate (70 to 80 dB) and high (above 80 dB) output without much effort on the volume dial.
For all-night use, aim to keep your white noise below 70 decibels, roughly the volume of a normal conversation. The sound should be loud enough to blend disruptive noises into the background, not loud enough to be the dominant sound in the room. If you have to raise your voice to talk over your white noise machine, it’s too loud. For infants and young children, keep the machine as far from the crib as practical and use the lowest effective volume, since there are no dedicated safe-exposure standards for that age group.