You made a great choice selecting the SoundTouch 300 Soundbar! Both of your surround speakers should be operating at the same level of volume, so it may be worth checking the audio settings to check nothing has been adjusted to give you more volume on one side. To do this, go to Menu > Settings > Speaker Settings > Select Speaker > Speaker Details > Audio Settings. From there, you can adjust the Center Level or Surround Level to your preference - let me know if this helps out!
in fact it is not the level of the centrol box for the surrounds, but the left surround is lower than the right, a considerable difference, I checked the wires, reset and returned to the factory settings ... until the calibration I did it again and it took me more than 2 hrs to do it and it didn't do any good!
Thanks for confirming that Guqueoliv!
What I would recommend doing next is swapping over the left and right surround speakers. You'll want to disconnect the speakers from the wireless receiver boxes and connect the speaker that is currently the left speaker to the right receiver box, and the speaker that is currently the right speaker to the left receiver box.
If the right surround speaker is now quieter than the left speaker, then it is the individual surround speaker that is causing the issue and you will want to reach out to your local support team to discuss the service option for this. You can find the contact information at this link, by selecting your country/region and then the 'Contact Us' option at the bottom of the page.
If the left speaker continues to be quieter than the right then it lets us know that the issue is somewhere else in the setup. What I would recommend doing at that point is swapping the L/R switches on the wireless receivers over. This time, if the right surround speaker is now quieter than the left speaker, then it is the wireless receiver box that is causing this issue and you will want to reach out to your local support team to discuss the service option for the receiver rather than the speaker.
I hope this helps! Let me know how the test goes!