How to monitor (mix) thru a cellphone?

I have a variety of non-standard monitoring options and want to add one more. Direct thru my cellphone w its tiny (tinny) speakers.



Android, the mic/headphone port uses a 1/8th TRRS jack, and I'm not familiar w any app that allows mic signals to be routed to the speakers.



Any help?

How to monitor (mix) thru a cellphone?