You can now sing a song using your mobile as a mic and sound will be played on Bluetooth speaker.
You can also use this in a group /class to give some speech.
Now fulfill your dream of singing using this app.

You can use headset mic as input for sound and Bluetooth speaker as output for sound with this app , you just need to set Media Audio enabled in speaker connected as Bluetooth. (Try toggling if output doesn't comes at once to speaker)

Any suggestions are welcome on [email protected]

Soon an update will be launched which will overcome the need of Bluetooth speaker.
Do not forget to share the app with your friends.
This app also has a option to increase microphone gain to catch more sound , but be alert to optimize it according to your need as it may take surrounding noise.