If you set up droneo with these intervals (here represented as cents...), at the base frequency A3 (220 Hz,) each reed will be 10 Hz sharper than the last one.
(redisplaying as Hz:)

That means when you play two adjacent reeds, the beat frequency is 10Hz, nicely in the alpha range.
adding more reeds, each will also beat at 10 hz . Using churn to move in masses of these beats, and pumping a bit of definition into it by using more complicated timbres, this gets pretty addictive. Drop the base frequency to D2 and the beats will slow down.

Here are the intervals in the tone spiral view .. you can move them around with your finger, etc.

At some point this year, I'll make it possible to share your droneo voices (and srutibox voices) via some simple method like cutting/pasting an ASCII version.