The HDR is supposed to amplify abilities you already have. But it doesn't work for everybody and isn't simply a device you active and makes astral travel happen conveniently. When it comes to device and schematics, that's pretty what you'll get. It might work for you. Or not.
Maybe you can take a look at the i-Doser. (I-Doser: Digital Doses).. Binaural beats can help your brain to get in the proper state in order to make astral travel more likely to take place. Using it while meditating can probably help you out quite a bit. If you wanna try it out, drop me a personal message on here, I'll send you a few doses in MP3 format so that you can see what it sounds like.
Astral Travel..You reminded me of something i read in a magazine in the early 1970s when the "New Age People" were getting into eastern philosophy, probably brought about by George Harrison from the pop group, The Beatles...Perhaps this video clip might retrieve your memory