How Does a White Noise Machine Work?by Julia Michelle
Understanding White Noise
White noise is an amalgam of sounds, within the human spectrum of hearing, all playing at once. The brain can only interpret so many sounds at one time and when it encounters the thousands of sounds that make up white noise, the brain interprets it as a distant rush or roaring sound. Imagine opening the window of a high-rise building in midtown Manhattan. The sounds of the traffic, people, and other noises all blend together so that no one sound stands out, resulting in a distant and indistinct "woosh." This is the nature of white noise. White noise gets its from the concept that white light contains all colors in the spectrum. Like white light, white noise contains all sounds.
Understanding White Noise Machines
A white noise machine, or sound conditioner, mimics or produces white noise by mechanical or electronic means. A mechanical sound conditioner uses a small fan to generate the white noise sounds and may have switches that adjust the air openings, changing the tone of the sound. The advantage of mechanical sound conditioners is that they produce a continuous and familiar sound. One disadvantage is that the volume is not adjustable. Electronic sound conditioners either produce a continuous, synthetic noise, or they play a pre-recorded noise in a continuous loop. Electronic sound conditioners usually play different types of sounds like ocean surf, rainfall or wind. The drawback to the looped sound is that there is often a small glitch where the beginning and end of the loop meets. Some people can hear this glitch, thereby negating the effect of the white noise.
The Affect of White Noise
White noise doesn't drown out other sounds but, rather, incorporates them. As stated before, when confronted with thousands of sounds at once, the brain is unable to differentiate one sound from another. When a white noise machine is running, any additional sounds get lost in the thousands of sounds already playing in the room. As a result, the sounds are still there, just dampened. Another affect of white noise is relaxation. Because all sound is reduced to a gentle, calm and consistent murmur, it calms the central nervous system. White noise machines are not as effective against sharp or intermittent noises and it is possible to override the effect of white noise by focusing on one sound or group of sounds. This is why it is possible to hear one person speaking over the murmur of a large crowd, or why an alarm tone or beep can be heard over the white noise machine.