Sonos Connect not working simultaneously with Line In and Out

So you’re playing the Connect’s Line-In to its own Line-Out? That should work. What equipment is connected to the Line-In and to the Line-Out?

Hi ratty,

Thanks for quickly replying. My Line In is connected to my macbook and the Line Out goes to a Logitech THX 2.1 speaker set.

@rejinjv,

I’m not understanding (at the moment) why you disconnect the line-out to your Logitech Speaker setup when playing the line-in from your MacBook? …or have I misunderstood that earlier comment? Also is the hum occurring because you have disconnected the line-out, when AirPlaying audio to the Sonos Ones, or does the noise occur even when the Logitech Speaker setup is connected? 

Are any of the products in your setup in close proximity to each other, the Bridge, or near to any other WiFi access point, or wireless device? 

Have you tried any of the mentioned devices in a different location, or have them perhaps use a different wall power-supply point (that’s if they’re using the same ‘common’ power supply point, or multi-point power adapter). It might be worth changing any interconnecting cables too, if you have spares available to you?

@Ken_Griffiths 

Thanks for taking the time out to reply. Apologies if I am not being very clear in my explanation. I think there are two scenarios:

1). When I connect the Line In of the Sonos Connect to my laptop via AUX cable, the music plays really well out of the Sonos One’s and Play:3 (since all my Sonos components are grouped together). However, if I turn on my Logitech speakers (connected to the Line Out of the Connect), there is a buzz/humm sound - and no music plays out of the Logitech speakers. Hence, I have to keep the Logitech speakers either switched off or the Line Out disconnected when playing through the aux cable connected to the Connect’s Line In.

2). In scenario 2, if I use AirPlay to play to the Sonos group, the music plays really well out of all the speakers including the Logitech speakers connected to the Connect’s Line Out.

I am not understanding why Scenario 1 is not working. I am not able to get the sound to play out of my Connect’s Line Out when the Line In is connected to my laptop.

I hope this explanation was clear. Hope you guys can help.

Regards,

Rejin

It sounds like some kind of grounding noise that’s passing from the Connect to the Amplified Logitech speakers… I’ve seen @ratty mention recently that there are isolators available to help prevent such noise, but I’ve not personally ever used one to comment on how well they work, or to recommend one to try, but I did come across this link…

https://soundcertified.com/what-is-a-ground-loop-isolator/

Maybe something like this will resolve your issue, but perhaps @ratty will chime in here and suggest some other things to perhaps try.

thanks @Ken_Griffiths  for the link to the isolator. I will check it out. However, if it was a grounding issue, shouldn’t I still have some audio output coming out of the speakers (or am I getting this wrong). I hear nothing when playing from the line in to the line out - but, the line out works perfectly when playing through airplay.

Actually, apologies for not responding completely to your previous queries:

1). My bridge is on top of the wifi-router - and I am guessing that is a bad thing. I am actually thinking of eliminating the bridge altogether - as with the Sonos One’s there should be a mesh network for all the systems to work together without the need for a bridge.

2). I’ll work on all the recommendations from you about having different power outlets and try that.

It sounds more like a lack of ground than a loop.

The Connect obviously doesn’t support Airplay directly. What happens when you get the Connect to play a source itself (e.g. a radio station) into the Logitechs? Try it with the MacBook wired (but not outputting audio) and also with it disconnected.

It is. You should separate them by at least 50cm. Better still, chuck the Bridge away. https://support.sonos.com/en-gb/article/remove-a-bridge-from-your-sonos-system

Done - re-setup the whole thing with the bridge eliminated. However, the line in audio still doesn’t come out of the Line Out speakers. Still streams to the other speakers if they are grouped together. 

Do you still think there is a grounding problem, and how should I go about fixing it ? 

The Connect is able to output to the speakers when I play Sonos Radio - with the Line In plugged into my computer and removed as well. there is some small buzzing for a second when I stop the radio - but the audio still comes through quite well.