DIAGNOSIS This is usually a digital audio signal handshake issue, not a speaker defect. It happens when the TV or source device sends an incompatible audio format or a corrupted signal burst.
FIX Go into your TV's audio settings. Change the digital audio output format from 'Auto' or 'Bitstream' to 'PCM'. This sends a standardized, uncompressed signal the soundbar processes more cleanly.
IF THAT DIDN'T WORK Replace the HDMI cable between your TV and the soundbar. A faulty cable can cause signal corruption. Use a certified High-Speed HDMI cable.
HEADS UP If the pop happens at the exact same volume level every time, it could be a failing capacitor on the amplifier board. That requires service.