I do not have  Sonos. Only Yamaha SR-B20A. But since this topic  interested me I replied to clarify things. With Phillips TVs,  there is confusion in the audio settings of the tv because they do not have options to select the type of sound like LG or Samsung tvs.

It's more of automatic settings but I have tried 3 soundbars , 2 of them high end ones on the tv and all of them do work in either one of the 3 options available in the tv audio settings.

Multichannel option is for soundbars that do not understand specific formats so the tv will output by downmixing to general dolby digital 2.0 or ac3 core  by stripping out the specific metadata from DD plus or Atmos to solve compatibility issues. 

The multichannel bypass option is for av receiver or higher end soundbars and standalone receivers with Atmos , DTS X or DD plus   I am not sure why  the Sonos behaves in that's way  but to me it looks like it only outputs stereo (2.0) even though in the website it's stated that it does a variety of multichannel formats. I think it's a sonos firmware problem OR I think it only outputs multichannel sound in E-ARC connections . ( Came across such discussion in other forums about the Sonos firmware defect) 

I have the Yamaha soundbar (SR-B20A) supports Dolby digital and DTS multichannel formats and outputs in virtual surround . I assume the Sonos is only giving  pcm 2.0 which is why u getting only stereo? In  this case u are getting stereo uncompressed which is a pcm signal. It should be clearer in quality than Dolby digital 2.0 or 5.1 which are equivalent to compressed audio like mp3 or AAC . So the problem here is yr Sonos . In my Yamaha soundbar when stereo uncompressed (PCM) is detected , the sound bar applies pro logic 2 to give a  surround like effect which in my opinion works great too .

As to yr question, yes the only solution is multichannel or stereo uncompressed should able to work with Sonos if u  have ARC only Phillips tv. The other alternative is to get different soundbar like LG or Samsung or JBL  with Dolby Atmos or DTS capability to output surround sound or an E-ARC TV for  Sonos. 

Does the Sonos remote or app had options to choose stereo or other surround formats? If u had chosen stereo in the Sonos remote or app it will play only stereo. Check that. 

If I am not wrong, there could be a problem with the Sonos firmware. Try update it . Since u stated that u were able to get Dolby once , yr settings set in both the tv and devices should be correct . 

1) One more thing u can try is under inputs , switch to the HDMI that your sonos is connected to. U will see a blank screen 

Then go to the general settings  and set HDMI to "ultra" . 

2) The other thing u can try is changing HDMI cables ,  get a branded premium high speed HDMI cable and try

Though this shouldnt make a difference in some cases it does especially when connection of PC scenarios where  both audio and video signal is transmitted together. And in certain cases the chipset of the tv has been designed to switch modes of transmission or due to some bugs at the engineering level, OS bugs ,firmware bugs  ect can all contribute to HDMI transmission problems.

lastly get something like nvidia shield tv or another set top box that can handle multichannel sound and try replicate the problem with the sonos by first connection to tv and then directly to soundbar ( if HDMI/IN is on the sonos)

The last won’t work. Sonos needs HDMI-ARC that the Nvidia does not do.

What do u mean ? Nvidia shield has no HDMI out connection? I checked on the web it does

I have the same  type Phillips tv and there is nothing wrong in how Phillips implemented the HDMI sound out  as I did some testing with my Yamaha soundbar that has indicators for which type of signal is coming into the soundbar 

Let's look at the options

Multichannel - this is like the automatic setting in Sony or LG tvs . what this does is pass pcm stereo or the downconverts to  vanilla version of Dolby like ac3 or 5.1 or DTS from the sources like Atmos or ddplus. If the source is YouTube,  mp3 it passes pcm uncompressed stereo. If the source is 5.1, atmos or DD plus  from netflix it will pass appropriately as surround ac3 downmixed .  If yr soundbar does not recognize Dolby digital plus or Atmos, it's best to choose this option as it auto recognizes the unsupported source and down converts to regular Dolby digital ac3 . 

Multichannel (bypass) - bitstream. Does exactly whats it's supposed to do. Pass the audio bits unaltered to the external connected HDMI sound system like soundbar or receiver to be processed .For more complex formats like ddplus Atmos DTS,Dolby true hd ect that need to be utilized with external equipment to reach full potential. Works best with high end soundbars like Sonos . If your soundbar/ receiver do not support the higher true hd Dolby or DTS formats, u will not get any sound.

Uncompressed Stereo  - outputs Uncompressed Stereo pcm from all sources    to  all soundbars both low and high end ones or any speakers  that do not need or work with multichannel capabilities ( examples are  bookshelf speakers like Klipsch the fives  or edifiers using optical or HDMI)  With this option the sound output is always assured regardless of 5.1 source or stereo. all sources will be converted to uncompressed stereo. 

the difference between multichannel (non bypass) and uncompressed stereo is this :

Multichannel - outputs stripped 5.1 from atmos/DD plus  source and PCM stereo from stereo only sources. lets say u connect a cheapo 2.1 soundbar , u will not get sound when the source is 5.1. but if the source is stereo only, u will get sound. Example is youtube videos ( some videos  are stereo while some are in 5.1 formats recently). basically this option outputs stereo as it is and downcoverts surround sources to vanilla ( if yr soundbar is just a 2.1 it cannot recgnise the downconverted surround too). This option is best suited to those   soundbars that come with 5.1 capabilities  and outputs sound in virtual surround but does not atmos or DDplus .

Uncompressed stereo - u will get sound regardless of any source be it be atmos . dd plus or true hd ect. All will be converted to stereo. This  is why this option best fits cheap 2.1 soundbars with no multichannel capabilities because they can accept only one type of signal; - stereo.



 

what happens if u connect a stereo only soundbar or speaker  and set the option to multichannel bypass?

the soundbar will behave the same as multichannel ( non bypass):

if the source is stereo the soundbar will output it , itf the source is 5.1 it will not  output any sound because the DAC / AV receiver in the stereo only soundbar can only process stereo if its  in the bitstream being passed over . if the bitsream contains 5.1 only ,  the soundbar DAC/ receiver cannot process it. since its not capable.

i have tried 3 different soundbars with varous format support on my phillips tv that has the same options . i could see no problem and all of them behave the way they are supposed to .

Creative stage V2 -  Stereo only soundbar

Not capable of  any  ac3 , dolby or dts or any surround format output

multichannel  - no sound 

stereo uncompressed - works with  all source formats input

multichannel ( bypass) : no sound 
this is because the soundbar DAC cannot  process dolby or dts formats 

Yamaha SR-B20A  - dolby digital / DTS:virtual X soundbar .

Not capable DD plus and atmos format output

multichannel  - works with all source formats input 

stereo uncompressed - works with all source formats input

multichannel( bypass) - works for stereo, dolby digital 5.1 and DTS input only.  no sound  in bypass when atmos or dd plus is fed.  this is because the soundbar DAC cannot process DD plus or atmos.

Samsung HW-N650 - dolby digital / DD plus / DTS: virtual X soundbar .

Not capable of Atmos. output

multichannel  - works with all source formats input. 

stereo uncompressed - works with  all source formats input. 

multichannel( bypass) - works with stereo, dolby digital 5.1, DTS  and DD plus input only . no sound  in bypass when atmos is fed .this is because the soundbar DAC cannot process atmos.

So this leads me to think that there is nothing wrong with phillips tvs. There must be something wrong with the  Sonos beam  as clearly its not behaving in the way its supposed to 

No, the Shield (I own one) does not have an HDMI-ARC output, so sends it’s audio to different pins on the connector. You cannot get sound on a Sonos soundbar connected to a “normal” non-ARC HDMI connection. So connecting an Nvidia “directly to soundbar” wil not work.

Ok I understand, I do not have a shield device with me. But on another occasion I have read a post in a forum that stated that a soundbar had no sound in HDMI arc but once they connect it to the normal HDMI in port they had sound 

No. The Sonos input is only on the ARC/eARC pins, and not the standard audio pins for HDMI. 

So the Sonos doesn't have HDMI/ in on it's side for direct connection to devices?

Your profile says you have an Arc: does yours have one?

Well It's part of the requirements to register. But I wanted to just answer the author's question 

No. It only has one HDMI port, meant to be connected to the (e)ARC on a TV.

Choose your TV speakers first again and ENSURE the volume level of TV SPEAKERS is set to ZERO  then choose HDMI 3 (Sonos) as your audio/sound option according to your photo above.  Ensure Dolby Sound is chosen on your TV.  Ensure Dolby Sound is chosen on your Apple TV (if you have one).  Test with a Netflix show or any other confirmed Dolby media piece.  This worked for me.  I didn't realize that even though I chose my Sonos Beam as my audio/source, my TV speaker volume itself was NOT set to zero.  

I am still not clear if you are understanding what I am saying.  I understand your options.  What I am suggesting to you to do is choose TV speakers FIRSTLY and turn the volume down to zero.  After you complete that task, change it and choose HDMI 3 according to the photo you provided.  ;)  

Bought a LG g series and the beam 2. Have shows and films with atmos and while the sonos is connected via the earc and the output is though the sonos, I cannot get the app to display anything other than showing stereo pcm. What the hell is going on?

The usual sound settings to go with on the LG TV are:

• Simplink & Auto-Power Sync: ‘ON’
• Sound Out: ‘HDMI ARC’
• HDMI Input Audio Format: ‘Bitstream’
• Digital Sound Out: ‘Pass Through’
• eARC: ‘On’
• DTV Audio: ‘Auto’

Thanks Ken, could not have done that without you. Much appreciated