I finally found a work around for playing music on my android phone on Sonos speakers. I was dissatisfied with using the Sonos app because: 1) Sonos does not sort folders or artists alphabetically (making it extremely difficult to locate a particular artist among 600+); and 2) the Sonos equalizer is too simple (one knob for bass - one knob for treble). The solution is remarkably simple: install the BubbleUPNP and cast your favorite android mp3 player app, podcast app, or other android audio stream. I have seen numerous forum inquiries about this issue, but none of the responses have descibed this simple solution.
I am so delighted that I can now play music from my phone to Sonos speakers with total ease.