I’m just wondering what technology or internal components would be needed to send audio from one master out to 30 wireless speakers over 100 metres, these wireless devices would be worn by people, I was thinking that a Bluetooth system would be used, help here would be greatly appreciated

 

FM headphones.

 

but how small could I get them components to be for the fm headphones and Is there any way of encrypting the signal

 

RE: "30 pieces of speachless wirers"

Maybe it SEEMS unneedly complicated, but actually by price, amount of invested job as well the audio quality I cannot to tell anything but Mic to Arduino-Nano ADC, that to Nordic-24L and other side Nordic-24L to Arduino-Nano and DAC, and DAC to speakers.

Costs- mic about 10 $, Arduino-Nano compatible Geek-Robot 0,99 $ and Nordic 1,02 $. Ach, ya, PS on basis of ADP1607 as it can with an ease to work with largely empty ONE battery (about 1,5 $). For using the single PS 3V3 only the Arduino crystall MUST be resoldered to 8 MHz, or apply two voltages.

Sizes: Geek-Robot 1x2 inch, Nordic 1x1,5 and PS 10x10 mm. Battery AAA, one. Equipp the Nordic with rather good and fast Vcc cap as the peak currents may overshot the average currents somewhere with factor of 10 or even 100.