This way I hope to add the play 5 with the extra boost of bass of a subwoofer, that later I can also use with a classic stereo reciever and loudspeaker. Buying a Sonos sub is not something I want to do because of personal sonoc preferences and beeing strictly bound to sonos.
Best answer by ryde
To follow up. I now have a third party subwoofer plugged to a sonos connect and it works great! I can adjust the volume separately in the sonos control app. And also when increasing the overall volume on my grouped setup of a single play 5 and the connect (plugged to the subwoofer) the levels adjust appropriately (the sub volume increase in the same ratio as the play 5 volume).
The crossover on the sub makes adjustments of the frequency range easy to match with the play5 to make it sound great.
The sonos connect triggers the auto turn on function of the subwoofer when I start a song. You may have to raise the volume a little if its turned down really low since some subs demand a higher signal to engage.
Overall this experiment has left me increadably satisfied. Amazing bass from a used XTZ w99 12 together with a used but as new sonos connect has left me with what I intended. Less money spent, better bass, better and more adjustments available for controlling the bass and lastly the flexibility to later team up the sonos connect with a full scale stereo setup with the bass connect to the amp at a later stage.
So I highly recommend this type of setup!