The Science of Sound
Studies on this matter are scattered far and wide and provide anecdotal rather than scientific evidence. However, there IS evidence. For instance, a study on the relaxing effects of a specific song, ‘weightless’ showed as follows:-
A study was conducted on 40 women, who were connected to sensors and had been given challenging puzzles to complete against the clock in order to induce a level of stress. Different songs were then played, to test their heart rate, blood pressure, breathing and brain activity. The results showed that the song Weightless was 11 per cent more relaxing than any other song and even caused drowsiness among women in the lab. It induced a 65 per cent reduction in overall anxiety and brought them to a level 35 per cent lower than their usual resting rates.
So here we see the direct effects of a specific sound/music piece on a group of people in a controlled experiment. Although the primary purpose of the experiment was not to prove the sleep-inducing effect, it was observed anyway, which probably arose from the very pronounced relaxation induced in the group.
Here is that song - Weightless
One must conclude then that the measurements of scientists have clearly shown that sound can help us to sleep.
Apart from Sounds - What Else?
My experience and belief tells me that sounds alone are not enough - human beings need to understand WHY things happen to them and WHY things work. That’s why any medical practitioner worth his/her salary provides informed medication .
There’s probably an intertwining of chemical and psychological effects in this combination - an effective pairing of the placebo effect with the expected effect of medication.