A piece on Wraiths

You could try visualising an old style radio Dial and slowly cycling through the different frequencies. (it needs to be an old one because all the new ones seem to be auto tune)
Once you have them commited to memory you should be able to listen to anyone of them, or all of them at the same time if you so desire.
The dial might help you to search the different frequencies at will as well so eventually you should be able to search any wave length just by thought.
After that ......practice ........a lot

Zygo

If anyone has trouble imagining a radio and different frequencies, you could try my method.
I imagine the different frequencies as a different colour. Then I imagine I am standing in front of a sunny open window with a small prism. As I turn the prism in the rays of sunshine the different colours flow from it. I then simply follow my chosen colour up into the realm it represents.

To pick up on colour vibrations just takes a little time and practice with a real prism, getting familiar with how each colour feels and reacts to you.
I hope it helps.

DEA.

Thanks Zygo for the details.
Thanks DEA for the colour idea.
They both sound great. I'll try them and let you know how it goes.