White noise doesn't necessarily have to come from a specialized machine. It can be created by many things around your house, such as an air purifier, old stereo, air conditioner, or anything that can make consistent sound throughout the night. White noise machines are proven effective for some babies and their colicky pain , while other infants seem to remain indifferent. The fact is that a white noise machine is able to mask disturbing sounds at night, and help people stay asleep, rather than lull them to sleep .
White noise can be any constant sound such as the purring of a cat, or even snoring. I’m not kidding; we’re co-sleeping with our baby, and my husband breathes loudly, occasionally even snores. At the beginning, I was afraid that he’d wake our daughter up after all of the hard work of putting her to sleep, but she seems to like his deep breathing and snoring, as it has never woken her.
The Science Behind White Noise Machines
By definition, white noise is a consistent noise evenly distributed across all audible frequencies. In other words, it combines all the frequencies a person can hear — and that’s twenty thousand of them — into one sound.
White noise reduces the difference between background noise and a “peak” noise, such as a sudden door slamming or the phone ringing. For infants who suffer from colicky pain or people who have difficulty staying asleep, it could be helpful to create a constant sound that masks activity from outside the nursery or a bedroom . It doesn't matter which kind of device you're using, it's only important to keep the sound continuous  and not too loud, but more on this in a moment.
Can White Noise Machines Be Dangerous?
According to research, sleep machines often make sound pressure levels that may be dangerous for infant hearing and auditory development . The American Association of Pediatrics recommends special care with these types of machines. The study involved 14 different white noise machines aimed especially at babies; all of them tested above the recommended volume of 50 decibels from crib or table-side distance, and some were even reaching levels of 85+ dB, which is VERY loud for a baby’s immature ears. Placing them at least two meters away from the crib should be fine. [5, 6]
What bothers me about these studies is the fact that they avoid listing the products that they test. It would be very helpful for parents to know at least which products were the worst offenders and surpassed the allowable noise limits.
Other Uses Of White Noise
Studies suggest that white noise helps not only with sleep, but with studying and work too.  The Journal of Cognitive Neuroscience published a study claiming that the random sound in the auditory range that we perceive as “sh” could boost one’s memory. The sound enhanced connectivity in between brain regions in charge of modulating dopamine and attention. This is good for facilitating learning in those with memory deficits, such as older people. What’s important to remember is that this is not any random background sound, but the sound we popularly call “shushing”. 
Sound masking showed the most successful way of enhancing sleep quality in loud intensive care units, according to patients.  Postoperative exposure to white noise in the form of ocean sounds helped patients with artery bypass as they have reported higher scores in the overall quality of sleep including fewer awakenings. 
The Bottom Line
We use technology too much, we drink too much, and we play our music and our babies’ white noise machines too loud. We tend to exaggerate and use things wrong, that’s in our nature.
As I’ve already mentioned, there’s no need to purchase a white noise machine to help your baby sleep, plenty apps are available for both iPhone and android users. It’s perhaps best to download an app to a phone without a SIM card that nobody is using, to prevent cell radiation as it can harm babies even before they’re born. [12, 13] YouTube is also full of these sounds lasting from five minutes to 12 hours. You can then mount your phone to a high-quality speaker for full benefits. Just keep the noise in the safe range mentioned above.
We tried several apps, but our daughter seems indifferent towards them. The only thing she likes is a shushing sound coming from us, and we shush her during the fussy hours, and every single time when we’re trying to put her to sleep. Shushing is also a form of white noise that people around the world equally understand and connect with calming a (colicky) baby.