I've been tinkering with using a pair of Ikea Symfonisk speakers as a way to bi-amp a much better quality set of speakers by adding binding posts on the back to tie into the Sonos amplifiers and using DC switches to cut off the internal drivers so I can just use this as a Sonos amp if I want. I also cover some experiments on whether to include Trueplay when calibrating. UPDATE: Folks have been asking about the driver impedance and a viewer measured them. Woofer is 4 ohms, tweeter is 7 ohms (would round up to 8 ohms). I'd stick with using drivers that are in the 4-8ohm range but the closer you get to 4 ohms for the woofer and 8 for the tweeter, the more balanced it may sound. These are the switches I used to disconnect the internal drivers: https://www.amazon.com/gp/product/B07FBQBGBR/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1 These are the style of binding posts I used - warning these were pretty poor quality so I'd look for a better brand: https://www.amazon.com/gp/product/B07Q9QRX52/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1 Recommended subwoofers on Amazon ~$100: Polk 10" - https://amzn.to/2RcWV1q Monoprice 8" - https://amzn.to/3696umd Note: any subwoofer will work as long as it's amplified and has speaker level inputs - if it only has RCA inputs, look elsewhere.