Gaven took the Spirit Crystal Sphere and handed it to Yeshandalah, saying, "Infuse spell slots into it, and it will activate. Each one-ring spell slot will allow it to play for five minutes and can be infused repeatedly. It's up to you to take it to the major cities and spread the word so that the whole Giant Dragon Coast will be informed about the atrocities of the Efanso necromancers."
This was the second improvement to the Phantom Broadcasting Stone: the quantification of the energy needed for playback. Although Psychic Power Points were the best energy source to power it, they weren't the best choice.
Compared to Psychic Power Points, spell slots interfaced with the Magic Network were more common in Felen and hence the most frequently chosen power source.