$ sudo apt-get update
$ sudo apt-get install libsox-fmt-ao 

libsox-fmt-ao is installed in your system.

Make ensure the libsox-fmt-ao package were installed using the commands given below,

$ sudo dpkg-query -l | grep libsox-fmt-ao *

You will get with libsox-fmt-ao package name, version, architecture and description in a table

libsox-fmt-ao package basic information: