Hi @WernerK, thank you for reaching out to us and welcome to the Sonos community. I appreciate your detailed post describing the issue as well as the steps that you have performed. I understand that you’re having an issue with the sound quality of your Sonos Arc. I’d be happy to help you out here. Is TV Autoplay disabled in the Sonos app? What happens when you enable it or vice versa - Settings > System > &Home Theater Room] > TV Autoplay?

Let me suggest the next troubleshooting and see if it works for you.

1. Unplug the HDMI cable from the Sonos Arc and the TV. 
2. Unplug the power cable from your TV, the Sonos Arc, and any connected audio source (such as a cable box or video game console). Wait 30 seconds before you plug them back in.
2. Reconnect the HDMI cable to your TV and the Sonos Arc. Inspect the HDMI cable to ensure it’s not bent or kinked and check to see that it’s fully inserted into both devices.
3. Update the TV’s software (if available).
4. Disable eARC on the TV.
5. Adjust the group audio delay - Settings > System > Tap your Sonos Beam > Group Audio Delay and then choose a delay option.
6. Check for Sonos update - Settings > System > Check for updates.

Let us know how you get on with the advice above and run a diagnostic report and include the confirmation number in your response for us to check. Also, let us know the make and model of your TV and the other devices connected to it. 

If you have any questions about this, please let us know. We will wait for your reply.

Unfortunately this is just how the Arc sounds, it has a very different sound signature to other Sonos products which have always been very musical with a full sound.

Not so the Arc which has been tuned to be impactful for movie watching at the expense of anything else in my opinion. I wouldn’t spend too much time trouble-shooting, there’s nothing wrong with your HDMI so don’t let that be a distraction. There’s really no point trying to retune or adjust EQ as I doubt it’ll change enough to your taste, people either really like it or don’t (I really don’t).

The smaller and considerably cheaper Beam performs much better for music playback (especially when paired with surround Ones) albeit with a more limited soundstage due to it’s reduced size.

I fully intended to upgrade my Beam to the Arc but after hearing decided not to and have kept the Beam for TV use. I’ve sadly now bought into another brand due to this which may eventually replace my Sonos gear as I expand it.

Hi @Rowena B. thank you for your response, but I don’t think the TV or connection is the problem. 
I am talking about music played / streamed through the arc. In my case it’s streamed via AirPlay. 
Does the Arc ‘know’ that it’s getting a stereo input? It sounds like he wants to multichannel the stereo input. 
I will try your proposals but as said, the Tv doesn’t seem to be the problem. 

Hi @Bernado,

thanks for your reply. That would really be a bummer! I bought this set for two purposes. Home cinema and music playback. I can’t believe the system itself isn’t capable of producing great stereo output. So then it must be software related in my opinion. 
Hope Sonos can change this in an update. 
 

Our Playbar 5.1 is excellent for music playback.

There's many posts on here about Playbar/ Beam users being disappointed with the ARC music wise.

I'm in no hurry to "upgrade" my Playbar tbh.

I’m pretty sure it won’t change other than perhaps some updates for stability issues, there was an active thread here on release of this product with people unhappy with the thin sound - https://en.community.sonos.com/home-theater-228993/sonos-arc-metallic-sound-6843110

There’s various comments about using different generation Apple devices for Truplay in that thread leading to differing results and also staying put in one place during the Truplay process. Whilst there may be some changes to be had with tinkering around with those things it’ll never change the general sound signature I’m afraid to the extent you (and I) will be happy with.

I think people have made their own minds up now and either have moved on or just got used to how the Arc sounds, the main focus of ongoing problems with this device on this forum now seems to be based around sound dropouts.

Hi @Rowena B. I did the above recommend steps and still streaming music sounds very bad. IT sounds if all the music is put through the center speaker only (no stereo effect at all) 

I ran a diagnostic report (182522425) while streaming music from apple music via the Sonos app. 
Please help because I really like the looks of the Arc but I hate how it sounds now. 
Thanks, Werner

Hi @WernerK, thank you for your response and for submitting the diagnostic. I’m sorry to hear that there’s no improvement with the sound. Upon checking the report, I don’t see any issues in your Sonos system that might be causing the audio problem. 

We really appreciate the time and effort you've spent in resolving this issue, it would be best for you to continue working with us over the phone to expedite the process. I recommend contacting our Sonos Customer Care support to perform further troubleshooting and to do some tests on the Sonos app to isolate the issue to provide the best option for you. If you have any questions about this, If you need help with any other information, feel free to reach out. We and the community are always here to help.

I just bought the Arc and I found a similar experience with the music play of the stand alone Arc.  If you have the sub and surround Ones/SL/Play-1, you can change that. 
 

I did some experimenting. First, I detached the sub and play:1s from the Arc and created stereo channels pair with the sub. No surprise that sounded really good, like the Sonos you are used to.  This is a reasonably easy step, it takes a few minutes, but the app does all the work. Then if you want to go back to the surround, it’s the same 5 min time commitment to reconfigure the 5.1. 
 

Now, there is an even simpler option, that I think gets you very close to the above. If you have the full 5.1 configure, go to the Sonos app, select the room, select “Surround Audio.”  In the surround audio screen you have the option for “Music Playback.” The default is “ambient”, change it to “full”. This allows the Ones/SL/Play:1s to play within their full range. 
 

when I did the above, I found the sound stage to be as full as when I decoupled the system. The only thing I may be missing is the stereo channels, however, I am not certain of that. 
 

I hope this helps. 

Yeah Im also a bit disappointed with the Sonos Arc playback for music and for movies. I love the Sonos eco system and the look of there products. I have a beam in the bedroom which sometimes I find sound better than the ARC. The ARC for me just sounds like its being held back and re strained all the time. I don't find it room filling at all. I also have a sub and ones.

My friend has a Samsung Q90r and that feels the room with ease and I feel like the sound is wrapped around me.. I really want to love the ARC but im never satisfied with the way it sounds at the moment.. Fingers crossed a software update can resolve this...

Yes there is no doubt using bonded surround speakers in full mode rather than ambient will create a more pleasing musical projection because less of the sound focus is coming from the Arc, helping to mask it's deficiencies for music playback.

Of course this does bring a potentially unwanted side effect of music coming from behind the listener rather than front facing, which some will find an unnatural way of listening to music.

This is how I have my Beam configured and I was hoping the Arc would give me an upgrade solution with a wider soundstage but it wasn't for me for the reasons stated in this thread (and elsewhere in the forum).

I'm still enjoying the Beam but as I said previously I sadly had to look elsewhere for a 2 channel music system.

I think this thread highlights that the while the arc does very well what it was designed to do (sound bar for home theater), it’s not what you would get for music listening.  
 

I have a play 5 (second Gen), same form factor as Sonos 5, so I assume the sound is the same. Now that maybe the finest single speak Sonos produces. I love how it plays music. 

Yes I agree though you can't blame people for being disappointed when they discover this, after all Sonos themselves sell it as a multi application device as described in the opening paragraph in its product page -

'The premium smart soundbar for TV, films, music, gaming, and more'.

That is true, and not only that, it sounds like the play-Bar, did a much better job with music. So based on both the claims and customers past experience, the Arc didn’t meet expectations in the area of music play.

But, it is an awesome sound bar/ theater experience