Connecting multiple speakers with wire

Wouldn’t it be simpler to correct your WIFI issues that it would be to run audio cable through your home? 
How old is your home?

What are the interior walls made of?

What router/ network do you currently use?

What have you tried to fix your connection issues?

You’ll need the Sonos combo adaptor. If you want to hard-wire all 3 you’ll need three of them - an adaptor for each speaker.  https://www.sonos.com/en-us/shop/sonos-combo-adapter-black

Then plug your phone into any of the adaptors via the line-in using an appropriate cable. Run Ethernet cables back to your router from each speaker. 
 

But, as ​@Pools-3015 says, fixing your wifi may be easier. Mesh WiFi, perhaps? It seems odd to buy wireless speakers and then wire them together. 

Reading argumentation like this, the idea of wiring the “wireless” speakers seams not weird but absolutely smart move.
Of course if your plan is to have a good party time, not to ruin it. 😀

Why not just Bluetooth to one speaker and group the others in. However your phone needs to remain close to the  original speaker.

Poor wifi was an issue stated in the original post. 

Oops 😂

👍😜

Also, if the wireless speakers are below the crowd, perhaps on the floor or tables, you are burying the speakers in water bags. Bluetooth is no better than WiFi in this respect. All of this may be inconvenient or frustrate aesthetic preferences, but it’s just part of the laws of physics that cannot be repealed.

thanks for the advice! Would hard wiring all the speakers through Ethernet prevent the music from dropping out? 

Because you won’t be transporting sound via WiFi, that is more susceptible to interference.

Hardwiring with Ethernet helps in many situations, but I can’t say yes, it will fix your connection issues. We do not know what your network consists of, what your internal walls are made of or how big your home is. 

Only a small terraced house, but thick old stone walls. 
WiFi signal constantly drops. 
So if I were to connect all 3 speakers with Ethernet cables to the router, they wouldn’t be replying on WiFi at all would they? Or am I better just using the line in on each speaker with 3.5mm and adapters? 

The thick stone walls will certainly challenge wifi signals.
Ethernet cables will eliminate the need for WiFi. 

If you have a phone into each speaker you’ll have independent music in each room. Or you can just have one input (phone or other source via an adaptor’s line-in), but group all rooms together to have the same music playing in sync from all 3 speakers. 
 

Note that Sonos do two adaptors. One is only for line-in; you need the Combo adaptor as I said in my earlier post. https://www.sonos.com/en-us/shop/sonos-combo-adapter-black
 

thank you for the info! Sorry to keep asking questions but I am totally novice when it comes to this stuff. 
So am I right in thinking… connect all 3 speakers with Ethernet to my router. Connect my phone through 3.5mm to one speaker (with the double adapter) and then the music will be sent to the other 2 speakers through the Ethernet cable and it won’t drop out as it’s a more stable wired connection. 
 

Yup, that should do it (unless there are still any network issues that need tweaking). But you’ll still need the combo adaptor for the other two speakers too, as they don’t have an Ethernet connector without the adaptor.