To get set up:
In the Sonos mobile app, look at “about my system” under Setting->System. Make a note of this.
Now, add a custom service by opening a web browser to http://[your sonos IP]:1400/customsd.htm
Then fill in the form with the following:
SID: 255 (or any other number in range 1-253 if you’ve added other custom integrations before)
Service Name: SomaFM Beta
Service Endpoint URL: https://sonos.somafm.com/
(make sure it starts with https:// or it won’t work)
Polling Interval: 10 seconds
Authentication SOAP policy: Anonymous
Click the ‘Submit’ button. You’ll get acknowledgement that the custom integration was added.
Now, in your Sonos app, browse the list of available content providers, and ‘SomaFM Beta’ should appear. Add it, and try to play a SomaFM channel. It should start playing without any of the annoying TuneIn ads.
It would be even better if the songs scrobbled to Last.FM as they played, but I haven’t seen this on any Sonos radio service so far.