Hi @Lucas Echebarrena, 

Welcome to the Sonos community. Thanks for reaching out to us and letting us know about your concern. Let me share with you some information about Trueplay.

Trueplay measures how sound reflects off walls, furnishings, and other surfaces in a room, then fine-tunes your Sonos speaker to make sure it sounds great no matter where you've placed it. 

• After you tune your speaker, you can make further adjustments by changing your EQ settings. These settings are applied on top of the adjustments already made by Trueplay tuning.
• If you move your Sonos speaker to a new location or change its configuration (like making or separating a stereo pair), you should go through the Trueplay tuning process again to update its settings.

You may try to retune your Sonos speakers, please check this article Undesired sound after Trueplay tuning to guide you. There are some scenarios where Trueplay tuning may result in an undesired change to the sound of your Sonos speaker. If you prefer the way your Sonos speaker sounded before tuning with Trueplay, you can disable Trueplay in the Sonos app. 

Please let us know how you get on with the advice above and then run a diagnostic report from your Sonos system. Kindly include the confirmation number in your response for us to check. If you have any questions about this. We and the community are always here to help.

Thank you very much for your answer.

The biggest problem is that the I really prefer the sound with Trueplay, the sounds is a lot more robust because of the adjustments. I would really try to avoid deactivating it. 
 

I did not change location or anything on the setup, from the beginning it was unbalanced, higher volumes on the right surround and lower volumes on the left one. 
 

The diagnostics number is 1956487920.

I tried all auggested actions, but none fixed the issue.

Thank you!

Best,

Lucas

Hi @Lucas Echebarrena, 

Thanks for your response and for updating us. Upon checking the diagnostic, there's no issue found that might be causing the unbalanced sounds of your rear speakers. 

Let me suggest the following steps if it will resolve the issue.

1. Remove surround speakers.
2. Group your 2 Sonos One SL and start playback to test the sound.
3. Ungroup your 2 Sonos One SL.
4. Create a stereo pair and start playback to test the sound.
5. Separate stereo pair.
6. Add surround for your 2 Sonos One SL. Start playback to test.
7. Run Trueplay and test the sound.

If the sound for your rear speakers still unbalances after running Trueplay, the next step is to factory reset your 2 Sonos One SL and repeat the setup. 

If the factory reset will not resolve the issue, I recommend contacting our phone support team to further look into this or possible product replacement. Please let me know if you have any further questions or concerns, we’ll be glad to assist you. 

Hi...Lucas, did  it help. I have -just like many others - the same problems.

i wonder if its up to us customers to trouble shout and come with a solutions. Many have the same problems. And for the price you pay for the full surround set, the least you should expect is that Sonos is working for a solution instead of letting customers try this and that.

Exact same problem here, despite multiple trueplay process....

Hi folks, thanks for reaching out to the Sonos community and for letting us know about your concern. Have you performed the steps recommended in this thread? If after doing all the steps and the issue is not resolved, it would be best to contact our phone support team for more in-depth troubleshooting steps. Please do not hesitate to reach out if you have further questions or concerns. We are always happy to help out.