Hi Simonnet! You may want to try changing the sound mode of the soundbar. Different sound modes will impact the audio being sent to the rear speakers. Should you continue to experience issues, please reach out to Samsung Support at: 1-800-SAMSUNG, available 8AM - 12AM EST, 7 days a week, or Chat with us on Samsung.com: https://www.samsung.com/us/support/contact/
^Tim