(Pro tip: if you'll be leading groups or classes, don't forget to include a headphone for the instructor.)
You will need 1 transmitter for every audio source played simultaneously, i.e., a yoga class with 1 yoga instructor would require 1 transmitter, and a silent disco with 3 DJs would require 3 transmitters.
You will need 1 transmitter for every audio source played simultaneously, i.e., a yoga class with 1 yoga instructor would require 1 transmitter, a silent disco with 3 DJs would require 3 transmitters, and 10 breakout sessions would require 10 transmitters.
