A sleep machine is a device which is designed to promote sleep. People with sleep disorders may use a sleep machine to help themselves get to sleep or to encourage lengthier periods of sleep, and sleep machines can also be used in environments where getting to sleep is difficult, such as a home near a major roadway. Sleep machines are often available at drug stores, and they can also be ordered directly from manufacturers.
Sleep machines work by producing random noise which is played at low volume. The noise is designed to be as neutral as possible, so that it does not distract people who are trying to get to sleep. Some sleep machines produce the sound digitally, playing a recording of randomized sound, while others use a fan to push air through small holes in the casing of the sleep machine, producing a quiet whirring.
When a sleep machine is turned on, it hums quietly, producing a noise like falling water, gently hissing air, or a mild wind. Some people refer to sleep machines as “white noise machines,” referencing the white noise which is often produced by sleep machines. They are also known as sound conditioners, in a reference to the fact that the noise masks other sounds from the outside, creating a neutral and pleasant environment.
For people who struggle with getting to sleep, a sleep machine's lulling sound can make it easier to fall asleep, and the gentle sound may also promote longer periods of sleep, allowing the body to enter the deep stages of sleep. A sleep machine can also be used to mask loud noises from the outside or the rest of the house, allowing someone to get to sleep even when conditions are noisy. The sound is quiet enough that it cannot usually be heard outside the room, and the use of a sleep machine to mask unwanted sound may be less cumbersome than wearing headphones or earplugs to bed.
The sound produced by a sleep machine should be unobtrusive and as random as possible. Sometimes, small variations in frequency can make a huge difference, and a sleep machine may become annoying to sensitive ears as a result. Relocating the sleep machine to a different area of the room or changing the surface under the sleep machine from hard to soft or vice versa can sometimes resolve this problem. Sleep machines are also usually adjustable, allowing people to alter the volume level and frequency of the noise to suit their needs.