Start here. There is no charge for a SONOS controller.

Thanks Buzz, have edited my original post - it’s to allow me to stereo pair 2 (or more if surround) different speaker types, which you can’t do through the Sonos app (I don’t believe).  

Stereo pairing dissimilar speakers isn’t permitted in the Sonos controller for a reason: it’s likely to produce an unbalanced sound with a potentially unstable soundstage, owing to the differing frequency and phase responses. Traditional HiFi speakers are sold in ‘matched pairs’.

While you might get away with it for surround speakers it really isn’t a good idea at all for stereo speakers placed in front of the listener. If all you want is a vague separation between left channel noise and right channel noise then go ahead, but don’t do it if you like to actually sit and appreciate the recording.

I completely appreciate that Sonos don’t really want me to do it, and I get I’m not going to get the best experience - I’ve got other Sonos speakers for that.  But yes, these are used as rear surround speakers rather than front speakers and have, so far, done a decent enough job.

and Sonosequencr lets me do it on an iPhone.  But do any Android apps?  

I was not aware that you were referring to an App. Probably you should contact the SonoSequencr author and request that he develop an Android version