Subwoofer Not Working with AV Receiver: No Bass Fix

When a subwoofer goes silent on an AV receiver but the rest of the speakers play, the problem is usually in the receiver's bass management, not the sub. The receiver decides what gets sent to the sub-out, and a couple of setup choices quietly cut it off entirely. Work the receiver side first, then the cable, then the sub.

Fix the receiver's setup

1. Set Subwoofer = Yes. In the receiver's Speaker Setup / Manual Setup, the subwoofer must be enabled. If it's set to None, the receiver sends the sub-out nothing — and redirects bass to the front speakers instead, which is why "the sub does nothing" but the system still has some low end.
2. Set the front speakers to "Small." With the fronts set to Large, the receiver sends full-range audio to them and little or nothing to the sub. Setting the fronts (and others) to Small routes bass to the sub. This is the most common "no bass from the sub" cause.
3. Set a crossover. Pick an LFE/crossover frequency (80Hz is the standard default). With no crossover, the receiver may not redirect bass to the sub at all.
4. Run room calibration. Audyssey / MCACC / YPAO and similar detect the sub and set its level and distance. If the sub was off or unplugged during calibration, the receiver may have marked it absent — re-run it with the sub on.

Then the connection and the sub

1. Use the right output. Connect the receiver's Subwoofer Pre-Out / LFE to the sub's line-level input with a shielded sub cable. Many receivers have two sub-outs — either works, but make sure you're in a Sub Out, not a spare analog output.
2. Wake the sub. Powered subs with an Auto-on mode sleep until they sense signal and can fail to wake at low volume — set the sub to On, or turn its level up, and confirm its power LED goes from standby (red) to active (green).
3. Set the sub's controls right. Turn the sub's level up to a sane midpoint, and set its low-pass/crossover to maximum so the receiver's crossover is in charge (otherwise you're filtering twice).

Why a stereo source can have no sub

Here's a gotcha (the same bass-management logic also applies when you add a subwoofer to a soundbar setup): many receivers only send the sub-out a signal in surround modes or when bass management is active. Play a plain 2-channel "Stereo/Direct" source and some receivers send full-range to the fronts and nothing to the sub. If your sub works on movies but not on stereo music, switch to a listening mode that engages bass management (or enable "subwoofer in stereo" if your receiver offers it).

FAQ

Sub is silent but other speakers play — where do I look? The receiver's bass management. Set Subwoofer = Yes, fronts to Small, and a crossover (80Hz). That's the usual fix.

The sub works on movies but not on music. A 2-channel Stereo/Direct mode can bypass the sub. Use a mode with bass management on, or enable your receiver's "subwoofer in stereo" option.

How do I know the sub is getting a signal? Its power light should go green (active) from red (standby) when bass plays. If it stays red, it's getting no signal — check the cable and the receiver setup.

Two sub-outs on my receiver — which one? Either Subwoofer/LFE pre-out works. Use a shielded sub cable to the sub's line input.

The whole receiver has gone quiet, not just the sub. That's a different fault — if the receiver shuts down or shows a protection warning, work through the receiver protect-mode / check-speaker-wires fix first.