You need to work with your family, or you have multiple devices and apps (e.g. WeChat) that you can use to make group calls, at least two, and at most nine.
Turn on the ringtone and volume and set up a group chat with the devices.
WeChat group chat group call function, calls connected to multiple devices.
When the call starts, bring the devices close to each other to generate feedback,
The distance, the space, the volume will have different effects.
(for example: press the phone's built-in speakers against each other, and the feedback speed and volume will increase.)
Do not restrict the operation of the musicians. You can do this without actively changing your voice. And you can also 'cough' into your phone, or play with family and friends.
No time limit.