iOS App That Turns iPhone Into Public Address (PA) Microphone for a Bluetooth Loudspeaker?

Any folks used an iOS app to transmit the audio picked up on their iPhone’s microphone into audio that is immediately conveyed to a connected Bluetooth speaker?

I was planning to connect a small, battery-powered Bluetooth speaker to my dog’s collar. My hope was that my voice would be louder and he would be more “receptive” to my command. :slight_smile: