The Case of the Missing Bass: Why Your New Soundbar Sounds Weak and How to Fix It

You just unboxed your shiny new soundbar system, maybe something like the LG S80TR with its promising wireless subwoofer. You’ve seen the reviews, you know it’s capable of shaking the room. You hook it up, play your favorite action movie scene, and… nothing. The dialogue is clear, the high notes are crisp, but the earth-shattering explosions sound more like a book falling on the carpet. You crank up the bass level in the app, but it just makes things muddy, not deep.

If this sounds familiar, you’re not alone. A user named Cory, reviewing his new system, captured this exact frustration: “Bass is non existent with hdmi earc. However if you’re okay with the audio optical connection the bass is back to where it should be.”

This is our first clue in a baffling mystery. How can simply changing a cable bring a subwoofer back from the dead? Is the high-tech HDMI eARC connection, lauded for its superior bandwidth, actually the villain? The answer is more complex and fascinating than you might think. Let’s put on our detective hats and investigate the case of the missing bass.

Suspect #1: The Connection Cable Conspiracy

It feels counterintuitive. HDMI eARC (Enhanced Audio Return Channel) is the modern standard, boasting a bandwidth of up to 37 Mbps, easily capable of carrying uncompressed Dolby Atmos and high-resolution audio. The older Toslink optical cable, by contrast, maxes out at around 1.5 Mbps, limiting it to compressed surround sound formats. So why would the “inferior” cable deliver better bass?

The issue isn’t about bandwidth, but about communication. Think of the connection between your TV and soundbar as a complex conversation. When you use HDMI, they engage in a process called an “EDID handshake” (Extended Display Identification Data). They discuss what each device is capable of—resolutions, audio formats, and more. Sometimes, this conversation goes wrong. A buggy firmware update on your TV or soundbar can lead to a miscommunication, where the TV mistakenly tells the soundbar it can only handle a basic stereo signal, stripping out the dedicated Low-Frequency Effects (LFE) channel—the very channel that gives your subwoofer its thunder.

When Cory switched to the optical cable, he effectively forced a simpler, dumber conversation. The optical connection doesn’t have this complex handshake. It just sends the audio data it’s given. This bypasses the EDID bug, and suddenly, the LFE channel is restored. The bass is back.

What to do: If you have weak bass over HDMI ARC/eARC, the first step is a full system power cycle. Unplug both the TV and the soundbar from the wall for 60 seconds. This forces them to forget their last failed conversation and attempt a new handshake. If that doesn’t work, try swapping to an optical cable temporarily as a diagnostic tool. If the bass returns, the issue is likely a software or compatibility problem between your devices. Check for firmware updates for both your TV and soundbar.

So, you’ve swapped to an optical cable and the bass is back. Case closed? Not quite. What if I told you the real culprit isn’t the cable, but an invisible thief lurking in the very air of your living room?

Suspect #2: The Invisible Thief in Your Room

Sound, especially low-frequency sound, is a physical wave. Imagine dropping a pebble in a pond. The ripples travel outwards, hit the edges, and bounce back. Your room works the same way with sound waves. Bass frequencies have very long wavelengths, often comparable to the dimensions of your room.

When a sound wave bounces off a wall, it interferes with the new waves coming from the subwoofer. In certain spots, the reflected wave crest meets an outgoing wave trough, and they cancel each other out. This is a destructive interference phenomenon known as a standing wave, or a room mode. It creates “nulls” or acoustic black holes in your room—specific locations where a certain bass frequency is almost completely inaudible.

[Image of a standing wave diagram in a room]

You could have the world’s most powerful subwoofer, but if your favorite chair is in a bass null, you will hear almost nothing. According to a study by the Audio Engineering Society (AES), moving a subwoofer’s position by just a few feet can change the low-frequency response at the listening position by as much as 20 decibels. That’s the difference between feeling an explosion in your chest and barely hearing it.

This is likely the single biggest reason people are disappointed with their subwoofer’s performance. They place it where it looks good—tucked in a corner or inside a media console—unaware that they might have placed it in the worst possible spot acoustically.

What to do: You need to find the best spot for your subwoofer, and the best way to do that is a technique called the “subwoofer crawl.” It sounds silly, but it’s based on the principle of reciprocity in acoustics.
1. Place the subwoofer in your main listening position (yes, right on your couch).
2. Play a familiar music track with a repetitive, strong bassline.
3. Get down on your hands and knees and crawl around the perimeter of the room where you might potentially place the subwoofer.
4. Listen for the spot where the bass sounds the fullest, tightest, and most even. That’s your subwoofer’s new home. That’s the spot where the room’s acoustics are helping, not hurting.

Now that we’ve mapped out the acoustic minefield of your room, it’s time to arm our sound system with the right commands. The battle for bass isn’t just fought with placement, but with numbers and settings hidden deep within the menu.

Suspect #3: The Settings You Didn’t Know Existed

Modern sound systems are complex beasts. They perform a task called bass management, deciding which frequencies go to the main speakers and which go to the subwoofer. The setting that controls this is the crossover frequency. For most soundbars, this is set automatically. However, in systems where it’s adjustable, a wrong setting can create a “hole” in the sound, where frequencies are too low for the soundbar to handle properly but too high to be sent to the subwoofer.

More critically, let’s talk about Phase. Most subwoofers have a phase switch or dial (0/180 degrees). This control time-aligns the subwoofer’s driver movement with the main speakers. If the phase is set incorrectly, the subwoofer can actually be producing a sound wave that is out of sync with the soundbar, causing—you guessed it—cancellation. It’s like two people trying to push a car, but one pushes while the other pulls. They’re working against each other.

Finally, there’s the AI Room Calibration, like the one on the LG S80TR. In theory, this feature uses a microphone to listen to test tones and automatically corrects for your room’s acoustic problems. However, as some user reviews point out, it can sometimes fail or produce strange results. This can happen if there’s too much background noise during setup, or if the microphone is placed poorly. It might misinterpret a bass null and try to overcompensate by boosting the signal, leading to distorted, “boomy” bass, or it might cut the bass entirely.

The Verdict & Your Action Plan

The case of the missing bass rarely has a single culprit. It’s usually a conspiracy between your connections, your room, and your settings. The good news is that you are now equipped to solve it.

Here is your step-by-step action plan to bring back the bass:

1. Solve the Connection:

   • Power Cycle: Before anything else, unplug your TV and soundbar from power for one minute. Plug them back in and see if the HDMI handshake fixes itself.
   • Check for Updates: Ensure both your TV and soundbar have the latest firmware installed.
   • Diagnostic Swap: If bass is still weak over HDMI, test with an optical cable. If this works, you’ve confirmed a compatibility issue. You can either stick with optical or contact manufacturer support.

2. Master Your Space:

   • Perform the Subwoofer Crawl: This is non-negotiable. Find the acoustically optimal spot for your subwoofer. Avoid corners if the bass sounds too boomy and undefined. A 2018 study in the Journal of the Acoustical Society of America reaffirmed that subwoofer position is the dominant factor in achieving smooth low-frequency response in a room.
   • Get it Off the Floor: Try placing your subwoofer on a dedicated isolation pad. This decouples it from the floor, tightening the bass and preventing your house from rattling.

3. Dial in the Settings:

   • Rerun Room Calibration: Try running the AI Room Calibration again. Ensure the room is completely silent and the microphone isn’t obstructed. If the results are still poor, turn it off and tune manually.
   • Check the Phase: While playing a bass-heavy track, have a friend flip the phase switch on your subwoofer between 0 and 180. Leave it on the setting that sounds loudest and fullest from your listening position.
   • Adjust Levels Manually: Forget the “AI Pro” modes for a moment. Set the soundbar to a standard or cinema mode. Go into the manual speaker level settings in the app. Start with the subwoofer level at 0 dB and slowly increase it until it blends seamlessly with the soundbar, providing a foundation rather than overwhelming the sound.

Solving audio problems can be frustrating, but by thinking like a detective and investigating each potential suspect systematically, you can transform a weak, tinny sound experience into the powerful, immersive home theater you were promised.