Here is a smart way to use sound to provision IoT devices with wireless configuration, Cloud connection credentials and more. Chirp (https://chirp.io) created enterprise-ready, cross platform SDKs for transmitting data over sound and the Azure IoT team collaborated with Chirp to implement a nice and easy way to setup an MXChip devkit and connect it to Azure IoT Central using just sound.
Get started with Azure IoT Central: http://azureiotcentral.com
Get started with the Chirp SDK: https://admin.chirp.io/
Get the code for the sample: https://github.com/Azure/azure-iot-experimental/tree/master/Chirp_IoT_Central
Create a Free Account (Azure): https://aka.ms/c9-azurefree