SpeakY turns a bunch of iPhones and iPads into a mini sound system. Just join the same WiFi network and one device becomes the microphone while the rest are speakers.
HOW DOES IT WORK?
First off, everyone joins the same WiFi network. Then one person begins speaking into their device like a microphone. Everyone else's device becomes a miniature wireless speaker.
IS IT FREE?
It's free for all of the listeners.
It's not free for the speaker. The person with the microphone should upgrade their account (via in-app purchases), otherwise listeners will hear interference.
Once the speaker upgrades their account, their broadcast will be free of interference. As a bonus, they will not hear interference from anyone else either.