Read this:

https://support.sonos.com/en-us/article/listen-to-your-turntable-on-sonos

Ok so, if I understand correctly, there is no way to connect my turntable to my symfonisk without buying something quite expensive…

Wouldn’t it be possible to send my TT signal in a Mac which is wi-fi connected to the Symfonisk?

Your least expensive option is getting a turntable that is compatible with Bluetooth and getting a Sonos Roam SL. You can pair the turntable with the Roam SL and share the Bluetooth audio to your SYMFONISK speaker:

https://support.sonos.com/en-us/article/share-roam-s-bluetooth-audio-with-your-sonos-system

Ok thanks for your help I will consider this option!

Wouldn’t it be possible to send my turntable signal into the in port of a Mac which is wi-fi connected to the Symfonisk?

The only connection possible between your Mac and the Symfonisk speaker is Airplay.  I’m not really sure how you can get the turntable sound to the laptop and out via Airplay, but if you did, that could work.  More a question for Apple than Sonos.

You are right, I said “wifi” but should have said “Airplay”. My Mac is already connected to my Symfonisk, and you are right, the thing is: how to get the turntable signal to get “in” the Mac.

Hence, a Mac issue and not a Sonos one, you are right.

Just to say, the headphones plug on a Mac includes a microphone entry, I guess having the right cable it should do it. The problem is: I don’t wanna buy the turntable without first making sure that it will work.
So even though it is not really a Sonos issue, I keep checking: has anyone here ever tried to plug a turntable into a Mac through the “in-out” audio port of a Macbook?

Thanks for help.

I’ve never seen any software that would support that concept…although I haven’t really been looking for it, either. 

I think, on further reflection, all you’re looking for is software that will play whatever is coming in on the microphone line in. That’s where the data will be coming from the turntable. The OS has the responsibility of generating where the output goes, AirPlay 2 or the Mac’s internal speakers. 

This makes it slightly easier, not having to look for two features in one software package. 

If you have not bought a turntable yet,  this one is an option since it can wireless connect to your Sonos speaker(s) without airplay or bluetooth.  However, this is probably overkill for your needs, and you probably better off with routing through your Mac or getting a bluetooth turntable and a Roam.