Diagnosis
This usually means the soundbar is receiving a very weak audio signal from the TV, often because the TV's own volume is being kept low or the output format is conflicting.
How to Fix It
Rule number one: make sure you're controlling the volume with the JBL remote, not the TV remote. The TV volume should be irrelevant. Then, check your TV's audio output settings. Look for any setting labeled “Digital Audio Out” or “HDMI Audio” and change it to PCM. Some other formats (like Dolby Digital) can cause low volume on this model. Also, disable any “Night Mode” or “Volume Leveling” features on the TV, as these compress the sound.
If That Didn't Work
There's a small chance the bar is stuck in a limited headphone output mode from a previously connected device. Do a full reset: Unplug the bar from power. Press and hold the Mute button on the top of the bar. While holding it, plug the power cord back in. Keep holding the mute button for about 10 seconds after it's powered up, then release. This resets all settings.
Heads Up
This is a compact, 2.0 channel bar designed for clear dialogue and modest room fill, not theater-shaking bass. Manage your expectations compared to larger systems.