I wanted to use SONOS with my Yamaha NS-AW194 outdoor speakers on my patio, but the amplifier offered by SONOS was just way too expensive for me at around $800. I was able to find some IKEA Symfonisk lamp bases (2021 model, 304.873.11) on eBay, whose technology I installed in the Yamaha speakers with some 3d printed adapters.

You can find my complete step-by-step instructions on instructables: https://www.instructables.com/Make-a-SONOS-enabled-Yamaha-Outdoor-Speaker-With-I/