When a powered subwoofer goes quiet, the fault can be in the settings, the cable, the subwoofer’s built-in amplifier or the driver itself. Working through these in order will usually tell you where the problem is.
Check the basics
- Power light. Is the subwoofer’s power or standby light on? If not, check the power cable, the switch on the back and the fuse, if it has an external one.
- Auto-standby. Many subs switch off after a few minutes without signal and wake when they detect bass. If the signal is low, they may not wake. Try setting power to “on” instead of “auto”.
- Receiver settings. Check the subwoofer is set to “yes” or “LFE + main” in your AV receiver’s speaker setup, and that the sub level isn’t turned right down.
- Cable. Try a different RCA cable and a different sub output on the receiver if it has two.
Test the subwoofer on its own
Connect a phone or other source directly to the subwoofer’s input using a suitable cable and play some bass-heavy music at low volume. If it works, the problem is in your receiver or its settings. If it doesn’t, the fault is in the subwoofer.
Common subwoofer faults
Plate amplifier failure
Most powered subs have their amplifier and power supply on a plate at the back. Heat, power surges and age take their toll, and plate amp failure is the most common cause of a dead sub. It’s usually repairable at component level.
Hum with nothing playing
A constant hum from the sub is often a ground loop between the sub and the receiver, or ageing power supply capacitors in the plate amp. See our guide to amplifier hum and buzz.
Rattling or distorted bass
Gently push the driver cone in (with the sub switched off). If it scrapes or feels rough, the voice coil may be damaged. A torn surround or loose panel can also rattle.
Getting it repaired
We repair powered subwoofers, active speakers and soundbars, including SVS, KEF, Bose, Klipsch, Velodyne, Yamaha and JBL. See speaker and subwoofer repairs.