The Villa Diletta has a split-A/C for the bedroom. We don't run the compressor at all at this time of year. We don't need it for heat or cold. Yet, we often run just the fan in the inside unit to mask noise. Here we are likely to hear braying donkeys, barking dogs, or early morning birds. The fan also prevents us from hearing the early morning prayer from mosques' speakers.
At home, we use a tiny box, heater fan for the noise it makes. In downtown New Westminster, we have to contend with the urban sounds of trains, noise from the Met bar patrons, and the annoying neighbhours who seem attracted to the upstairs apartment.
I am not quite sure what prompted me to type white noise into Google. Now, I am interested in getting a dedicated sleep machine. I knew nothing about this category of gadgets. I am frequently astonished to find new products which exactly fit my wants or desires. Obviously, sleeping with sound is not only something unique to us. Isn't it nice to know one isn't unique after all! Apparently, these devices are used to help babies stay asleep too. Most are electronic nowadays.