If they’re set up as a stereo pair, I’m not sure how you could “move the Line in” to the other speaker. Is it possible that they’re not actually set up as a stereo pair, but two separate “rooms” that you’ve grouped together?

If they’re set up as a stereo pair, they’d show up as a single “room” in the Sonos controller, and be designated as (R+L) in the room. If you have two separate rooms, like “Living Room” and Living Room 1” then they’re set up not as stereo, but are mono speakers that you’ve grouped together, most likely. 

When you’re setting up the Line in, you should have just the one room that you’re sending the signal to...the one room that indicates the (R+L) in the room name. 

@Airgetlam - thank you for the response. Yes, definitely a stereo pair. 
 

That said, the turntable as an “input” only ever shows as (L) if connected to left speaker or (R) if connected to right speaker. I’ve attached screenshots. I have tried everything - including full factory reset.  By “move the line-in”, I meant physically move the cable from the Turntable to the Line-In port of the Left speaker or Right speaker.
 

I have a stereo pair of Sonos Fives and if I cable to either, or both, line-in port(s), they each ‘show’ as active when something is plugged-in.

Also the chosen line-in audio plays to both speakers when the stereo paired ‘room’, which is called ‘Fireplace’ in my system, is selected for playback of the line-in audio.

See attached:

My thoughts are to perhaps first separate the stereo pair of Fives and then try each speakers line-in port, just to ensure that it is working correctly (maybe power-cycle the speaker, if necessary, and double-check the cable is seated correctly, or maybe even try a different cable).

If no joy with those things, consider a factory reset of the one ’problem’ speaker only - do not factory reset all your products.

Once you have each line-in working correctly (hopefully), then go onto stereo pair them and see if the both devices then work.

Also, double check the wiring. A missing channel is often due to a miniplug not pushed in all the way, or an RCA connector in the wrong output/input.

Thanks, all! I will check these things and report back. Really appreciate all the help!

In addition, it’s worth double checking that the cable in use, plugged into the back of the Five, is a stereo cable, and not a mono one. I think I’ve finally gotten rid of all my legacy mono cables, but it’s something that has bitten me before. 

Alright… Double checked everything.  Confirmed cable is stereo cable and tested channel functionality.

Separated “Stereo Pair”.  Found that speaker physically to the left worked with Line-In, but speaker physically to the right did not.  Rebooted Right speaker.  No change.  Factory reset Right Speaker - this resolved the Line-In Issue.

Confirmed able to play Line-In on either Left or Right speaker (still not in “Stereo Pair”).  Setup Stereo Pair - music only plays from the speaker where cable is connected.  Removed Stereo Pair and put both individual speakers into a grouped room - music only plays from the speaker where cable is connected.

Sigh...

What is your Autoplay room set to? Please tell us more about your network (mesh, access points, wired Sonos component?).

What happens if you use line in from a phone rather than the turntable?

Some things to perhaps try.. 

Maybe try the speakers on a different 2.4Ghz WiFi channel on your router (using channel 1, 6 or 11) and set the channel-width to 20MHz only… if you are using SonosNet (with one Sonos device wired to the main router) then set that so it’s channel is at least 5 channels away from your chosen router channel. Also ensure any wired device is not a Sub or HT surround and is positioned at least one metre away from your router. 

If using a grouped ‘room’ setup (rather than paired) see what happens when you increase the buffer using the Audio Delay option in the room settings..

Also perhaps see what happens when you change the line-in audio compression to ‘compressed’ in ‘Settings/System/Audio Compression’.

This sounds like a possible wireless network issue. The right unit should take its stream directly from the left, assuming they’re both on the same channel. 

@ratty @John B - Yes, I am starting to think this could related to my wireless network - although not 100% sure.  I have controller based Aruba Wireless in my home, as I am in IT, so this isn’t your traditional consumer grade wireless product.  I do see that the speakers are both connected to wireless, but one has negotiated 2.4Ghz and the other has negotiated 5Ghz - as such, they are obviously also on different channels.

I guess my confusion is that IF that were the issue, I wouldn’t expect Stereo Pair to work at all, but it does when steaming Pandora, Spotify, etc. in this exact same configuration.  That all works flawlessly - it’s literally just the Line-In that doesn’t use both speakers.  Do the speakers function differently with a line-in source vs streaming with regard to how the sync/pair?

@John B - Autoplay is set to “Bedroom” which is the room where the Stereo Pair resides.  I am going to try to find my audio cable for my iPhone to connect Line-In from it to see if I get a different result.

@Ken_Griffiths - Yes, I have tried all the different options for compression - no change.  Also tried all the different options with audio delay - no change. 

Line-In, at least in Uncompressed form, is more demanding than the other sources listed. It’s WAV/PCM, with shallow buffers by default.

I suppose one could try fiddling with the compression and/or delay (buffer) settings, but to be honest the combination of 2.4G and 5G wireless connections across the two units is pretty horrid. Inter-unit latency could be decidedly variable.

I’d suggest fixing the network such that both units are on the same channel. They’ll then be able to stream directly peer-to-peer. 

With those connections direct routing between the paired speakers is prevented. It is possible that the system copes with the alternative routing better with other sources. Although I would have thought using compression and delay would have got round that.

As an experiment you might try wiring a Sonos speaker to your router so that everything connects over SonosNet. 

Sorry, I skipped the fact that the OP had already tried compression/delay tinkering.

It’s conceivable, but not necessarily logical, that Sonos does something different with stream distribution for Line-In -- multicast vs unicast maybe -- and the Aruba system is obstructing traffic between the two bands.

It’s a strange one and ‘perhaps’ maybe related to your Aruba WiFi and the different WiFi bands - but next maybe try the speakers on SonosNet instead and see if that resolves the matter for you.

I’ve tested both line-in’s on the ‘Fireplace’ Five stereo pair here and both play to the pair - however I’m currently using a SonosNet setup.

It definitely ought to work, once the network is sorted out.

I’ve also used a stereo pair in the total absence of a central network, with Line-In fed into one unit. They SonosNetted together to form an AutoIP island, and both played fine.  

Appreciate all the help here.  I am going to give the SonosNet option a try.  I will need to move the equipment around a bit, so I will do that and report back.  Thanks!

@ratty @Ken_Griffiths @John B @Airgetlam @jgatie - You all absolutely ROCK!  Setup one of the Five’s to hardwire which changed the system over to WM: 0 (SonosNet) and now my Stereo Pair works perfectly!  Thank you all for your assistance and suggestions.  This is a great forum!

Even better, it is working with Audio Uncompressed and 75ms Audio Delay.  Very Happy!

For vinyl, where there's no lip sync requirement, I'd recommend a delay setting of 150ms. It'll provide a tad more stream resilience, without upsetting the whole needle experience. 

@ratty - Good Idea.  I wasn’t having and issues with 75ms with the Five’s (as they are only 3 feet apart).  That said, I picked up a One today for my office, and that would blip when playing from the turntable. Changed delay to Medium (113ms) and that resolved that issue.  Want to keep it as low as possible, but may have to bump it to 150ms as I add more devices.

Question about that.  Does each speaker act as a repeater when using SonosNet, or do they all have to connect back to whichever speaker has the physical hardwire?

It rather depends. The stream clearly originates from the unit hosting the Line-In, but as for how it gets distributed there are several factors in play.

SonosNet is a Layer 2 mesh, where any node can talk to its peers. So, yes, they can be thought of as repeaters.

However the active Layer 2 topology is determined by STP (Spanning Tree Protocol), which in practice means that SonosNet will try and minimise the number of wireless hops back to the wired network. But overlaid on that is the Direct Routing topology which shortcuts the spanning tree topology for the stream within a group (or stereo pair, a special kind of group).

Then there’s Layer 3 (IP), where a group will try to use multicast if it can, unless the underlying network obstructs this in which case it could resort to multiple unicasts...

It would perhaps be illuminating to review your network matrix, which will at least reveal the SonosNet spanning tree topology. Go to http://x.x.x.x:1400/support/review where x.x.x.x is the IP of any player. Click on Network Matrix to expand it, and post a screenshot. 

Very Cool!  I like that the network map is built in!  Turntable is connected to “Bedroom (L)”

Okay, a relatively simple situation, which seems to be happy. Good signal strengths, with the Line-In into the root node. The latest models can’t display ambient RF noise data in the left column of the matrix, due to compatibility issues, hence the white cells there. Interference is therefore a bit of an unknown quantity. A burst could have accounted for the ‘blips’ in the Office, before the buffering was tweaked up. 

As a tip, if you plan to group Bedroom with Office then start with Bedroom and add Office, not the other way round. It will help optimise the wireless network paths. The first room in a group (and usually the left node thereof if a pair) fetches the stream and sends it to the other members. 

@ratty Thank you!