Energies, just like light, need a carrier. Energies are not a bodiless, shapeless woo-woo thing: they are vibrational in their nature. In total vacuum, the energy cannot advance: there is no carrier.
What are suitable carriers for energies? Air, liquids, especially water, and sound. Obviously sound is already a derivative: without something to carry the sound vibration, there is no sound…
I’ll use sound to illustrate.
If there is no carrier, if there is no matter, sound dissipates.
But sound itself can become a carrier. The energy you want it to carry will modulate the “original” sound, it will combine: you will get the original sound and the inaudible sound of the energy.