Watch how the components of a fixed/permanent counter hearing loop are gradually built:
Hearing loop (copper wire shown with yellow rectangles, usually invisible).
Microphone feeds the hearing loop, with a power source
Staff person speaking into the microphone.
A blue mist where the electromagnetic field of sound is created, once the staff person speaks into the microphone.
An adult and child listen directly to the sound, using a telecoil in their hearing aid and cochlear implant, respectively. They hear the speech clearly with minimal background noises.