We started off with a fan/ air purifier thing. We turned it on for every nap and nighttime. Then it started making a weird sound/smell and freaked us out. So we put in a portable speaker, ipod, and a brown noise "song" on continuous in her room. That worked well, except when the speaker's batteries died it would make a horrendously loud static noise, scared the shit out of us- so that happened every 3 days. We also love this white noise app on our phone- we use it at the grandparents, traveling, etc. We put our phones on airplane mode....and play away. But we don't want our iphones tied up in her room... how could we live without them in the middle of the night?
THEN we got smart. We purchased a sound spa- white noise machine. So simple. So perfect. It was at bed bath and beyond, also you can find some affordable ones on amazon [white noise machines]. This one plays about 6 nature sounds- soothing, but we like the white noise best. I covered up the clock with black electrical tape. And the best thing is it plugs into the wall! No batteries, however if you want it to be portable it can be. And it just plays and plays until you turn it off. PERFECT... that only took us 10 months to figure out.
This is awesome for our smaller house, where we like to watch TV after she goes to bed, maybe load a dish or two in the dishwasher...you know living on the wild side. So this cancels our sounds we make. She sleeps quite soundly, we can still hear her peeps on the monitor through the white noise. I read that the white noise volume should be set to if you were standing in your bathroom listening to the shower and we turn it down a little from that (talked about here in this article, it's no where near scientific research... but it appeals to my motherly instincts/needs).
I think this will be important to have one for cora... one for us... and down the road one for the next babe. One big house-o-white noise.. So synthetically peaceful.