Symptoms
- Other speakers work but the sub is silent
- Bass is very weak compared to before
- Sub's power light is on but nothing plays
- Sub worked with one source but not another
Likely causes
- CommonSubwoofer's own volume/gain turned downPowered subwoofers have their own volume dial in addition to the receiver's setting.
- CommonReceiver's speaker configuration set to 'no subwoofer'The setup menu needs to know a sub is present to route bass to it.
- CommonLoose or wrong RCA/LFE cable connectionSubwoofers typically connect via a single RCA cable to a 'subwoofer' or 'LFE' output on the receiver.
- PossibleCrossover frequency set incorrectlyAn overly low crossover can send almost no content to the sub depending on the source material.
- Less commonSub's internal amplifier failedMore likely if the sub's power light doesn't illuminate at all.
What to do
- Confirm the subwoofer is powered on and its own volume/gain dial isn't turned all the way down.
- Check that the RCA cable is firmly connected to the receiver's 'Subwoofer' or 'LFE' output and the sub's 'input' (not 'output' if it has both).
- In the receiver's speaker setup menu, confirm the subwoofer is set to 'Yes' or 'Present'.
- Adjust the crossover frequency higher (e.g. 80–120Hz) to send more content to the sub.
- Try a different RCA cable to rule out a bad cable.
- Play content known to have strong bass (a movie explosion scene or bass-heavy song) to more clearly test output.
Tools and parts
- Spare RCA cable
Subwoofer RCA cableSearch: “subwoofer RCA cable”
When to call a pro
If the sub's power light won't turn on at all with a confirmed-good outlet, its internal amplifier likely needs professional repair.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.