Uses cvlc
to create an http stream of your local audio and sends it to the chromecast.
$ (sudo) npm install -g chromecast-unix-audio
Make sure you have the cvlc
library installed on your preffered os, some examples:
Fedora
$ dnf install cvlc
Ubuntu
$ apt-get install cvlc
When installed globally just do:
$ chromecast-unix-audio # Stream started at: http://0.0.0.0:xxxx/pc.mp3
And it will automagically send it to a founded chromecast.
There is a delay of about 10 seconds.