Several positive comments about Schumann generators, which I have not tried, so I'm intrigued. What should I look for when selecting one?
It looks like there's a lot to choose from but really its one or two almost identical circuit boards and what looks different is really nothing more than the box it comes in. I discovered this when reading reviews and one that sells for $400 when the reviewer opened the plastic case the photo of the inside shows the exact same circuit board sold on eBay for $12.
They all use a 5V DC power supply, and many come with a USB cable so all you need is a USB charger and you're in business. Or you can buy the one Synergistic sells, it has the fanciest box of all, and its own power supply, and the highest price tag, but look close wouldn't you know the power plug label says 5V DC. Hmmm....
People will tell you put them 5 ft up off the floor and sure enough the most expensive one Synergistic sells is a tower. But they also have the black box that sits right on the floor. If indeed that's even what these are, not like I know for sure, could just all be one big coincidence.
Anyway the ones I have are in different locations including one down low right by the power conditioner, and if there is any difference between any of them its really hard to tell. So I would just get whatever's cheap or looks okay to you and put it wherever you have an outlet, sit back, and enjoy. No matter what I can just about guarantee you will be shaking your head trying to figure out what the f is going on, and not caring, because its deep and black and natural and you just want more.