Why Your Subwoofer Sounds Distorted and 6 Working Fixes

Feeling those thumping bass lines and explosive movie effects brings home theater excitement. But when your trusty subwoofer sounds distorted, muffled or ragged, it really kills the experience. Before shelling out for new gear, try these troubleshooting tips to combat common causes of a sub sounding bad.

We’ll cover both wiring and settings issues making subwoofers sound distorted and how to remedy them. With some strategic tweaks and tests, you can get that tight, house-shaking bass back in no time. Let’s dive in.

Why Your Subwoofer Sounds Distaorted

There are several typical culprits behind a subwoofer outputting distorted audio:

1. Over-driving the Sub

Pumping your subwoofer volume too high can easily overload the driver and built-in amplifier leading to muddy, cracking distortion even if main speakers seem fine at the same levels. This requires immediate gain reduction.

Think of it like blowing out your voice by screaming – you stress vocal cord components and get a raspy sound from pushing too hard. Subwoofer drivers and amps exhibit similar strain behaviors when over-driven.

Set your subwoofer volume dial back below 75% as a good maximum target level. Super hot master volume levels from the AV receiver can also send excess signal to subs so keep an eye on that as well. Let dynamic boost features add punch on transient low frequency effects rather than maintaining dangerous high levels.

2. Incorrect Wiring

Faulty subwoofer wiring presenting impedance issues between the AV receiver and sub can also introduce distortion even at moderate volumes. Cold solder joints, thin cheap speaker wire gauges too long, unsecured connections and jack or connector damage can all present excess resistance impeding proper amplifier current flow and power transfer.

Testing connections and cable integrity by wiggling wires while playing sub intensive content clears up any distortion issues stemming from faulty wiring interfaces. Examine jacks for broken pins or corrosion buildup as well.

3. Blown Voice Coil

In older subwoofer hardware, prolonged overdriving past design limits can eventually cause permanent damage to the internal driver voice coil windings as heat builds up. Voice coils are delicate copper wiring components which translate amplifier signals into physical cone motion. If damaged, they generate scraping and distortion sounds even at normal levels needing full driver replacement.

Avoid running speakers beyond around 90% volume for long durations and power down systems before making wiring adjustments to prevent inadvertent dangerously high transients. Let built-in limiters do their job.

4. Poor Subwoofer Placement

Shoving a subwoofer into extremely cramped positions can greatly impede driver excursion and introduce port turbulence or early reflections causing harmonic distortion too.

For example, tucking subs away under furniture or inside tight cabinet alcoves restricts cone movement necessary to pump out clean low end. Ported designs perform even worse in confined areas as vent air turbulence distorts output.

Placing a subwoofer directly against a wall, especially when front or rear ports face boundaries also muddies sound quality, requiring positioning tweaks pulling them at least 8 to 12 inches out for better breathing room.

Experiment moving the subwoofer to less obstructed spots allowing both front and backsides unimpeded space. Try diagonal center room placements or along the middle of front and side walls if possible. Keep rear ports at least a foot from any boundary for starters.

5. Room Resonances

The inherent acoustic characteristics of any listening space also play a huge role. A subwoofer energizing loud resonant room modes can greatly accentuate certain lower mid-bass frequencies far above others. This imbalance manifests as both localization and ragged distortion problems demanding acoustic treatment to tame.

Resonant modes occur based on room dimensions, geometry and construction materials interacting to emphasize discrete low frequency bands while suppressing adjacent notes. Dimension ratios causing excessivebuildup down to 30hz up to 80hz are common without careful placement planning.

Wall composition and quantity of bare parallel surfaces also play a large role. Bare drywall or concrete surfaces encourage loud boomy resonances and distortion versus rooms with plenty of diffusion or damping from window drapes, furniture and textured materials.

Strategically place thick acoustic absorption panels at parallel walls and room corners to reduce sloppy reflections and muddy resonances. Bass traps in corners also help clean up accentuated resonant bass notes.

How to Fix a Subwoofer that Sounds Distorted

fix subwoofer sounds distorted

Luckily, many common subwoofer distortion culprits can be easily corrected through careful troubleshooting:

1. Reduce Subwoofer Volume

If your subwoofer starts sounding ragged, muffled or buzzy only when playing at louder levels, immediately reduce the gain volume to around 50% output. This reduces strain on the driver, amplifier and wiring while assessing issues. Distortion stemming from simple overdriving requires lowering levels long-term.

2. Check Wiring Interface Connections

With levels reduced, power down the system and methodically check that positive and negative subwoofer cable connections maintain proper polarity on both the back of the subwoofer as well as the AV system preamp outputs. Loose plugs, damaged pins or wrongly assigned amp channels introduce distortion.

3. Test Alternate Subwoofer Placements

Experiment moving the entire subwoofer cabinet first towards the center of walls and away from corners which excite unwanted room resonances. Also angle front facing drivers diagonally across room corners for enhanced low frequency diffusion.

Face rear firing subwoofer ports completely away from walls allowing several feet of clearance. Observe changes in distortion profile with content playback when adjusting positioning. Move seating areas and equipment racks around as well.

4. Apply Strategic Acoustic Treatment

In problem rooms, strategically place thick acoustic absorption panels at rear walls, parallel side walls and room corners to reduce sloppy reflections causing audible distortion and boominess. DIY or professional bass traps extend absorption lower to clean up resonant bass nodes directly.

5. Upgrade Subwoofer Gear If Necessary

As a last resort if extensive wiring scrutiny, positioning and acoustic changes don’t fix distortion problems from an aging sub even played moderately loud, consider a new model with higher continuous power amplifier, larger driver elements and upgraded cabinet construction.

6. Isolate Subwoofer Signal Chain

Unplug all other speakers leaving only the subwoofer connected and test distortion behavior across various content. If issues disappear, this points to a problematic integration zone with main speakers crossing over. Engage external crossover filters to isolate sub and re-run room correction calibration.

Additional Advanced Subwoofer Distortion Troubleshooting

why my subwoofer sounds distorted

Here are some other advanced tips for tracking down trickier causes of spotty, intermittent subwoofer distortion issues that come and go:

Tip #1 – Use Alternate Low-Frequency Test Signals

Instead of relying only on familiar bass-heavy movie or music tracks to judge subwoofer distortion subjectively, use alternate test signals like frequency sweeps or sine wave tones. The Arendal Sound Test CD contains various low end diagnostic tracks perfect for revealing ragged distortion. Most pro calibration software tools also generate sweep signals.

Tip #2 – Walk Around While Testing

Play 20 to 80hz subwoofer test tones at moderate levels as you carefully walk around multiple seating areas in the room. Distortion stemming from strong room resonances exhibits strong localization to small sweet/sour spots demanding acoustic damping treatments. Where you sit or stand greatly impacts what frequencies sound boomy or rough versus even neutral positions.

Tip #3 – Re-Mount the Subwoofer Driver

Mechanical issues with sub components can also be tricky root causes. Remove the built-in driver to inspect surrounds, spider, voice coil and dust cap for signs of aging deterioration or damage. If okay mechanically, securely re-mount driver to baffle and retest distortion behavior before assuming the worst.

Tip #4 – Calibrate With Measurement Microphone

For home theater usage, engage your AV receiver’s suite of auto room correction calibration tools. The process sets proper level, distance delay and applies room EQ DSP for the subwoofer cleanly integrating it with main speakers in one seamless system. Run this after moving sub or room furnishings.

Tip #5 – Reduce Main Speaker Bass Output

Set a 60 or 80hz crossover to divert deep bass away from towers down to the mono sub channel. This prevents tower woofers from localizing or distorting within their limited low end bandwidth range. It also avoids overworking sub amp channels trying to keep up with all speakers playing low information simultaneously.

Conclusion

It’s frustrating when your otherwise amazing subwoofer sounds distorted. But with focused troubleshooting across volume overdriving, wiring faults, placement issues and room interactions, the majority of problems can be remedied or at least significantly improved.

Implement the wiring, positioning, upgrading, and acoustic treatment tips covered here to help restore hard-hitting, room-filling, and distortion-free subwoofer audio glory once more. Carefully pinpointing root causes separates simple fixes from necessary component replacements if older gear is ultimately failing.

FAQs on Subwoofer Sounds Distorted

Q: Why does my subwoofer sound good sometimes but not always?

A: Intermittent sub distortion issues that come and go can stem from several common culprits:

Faulty wiring presents more resistance as connections shift around from vibration or thermal expansion and contraction cycling. This may require soldering suspect joints.
Certain ultra-low frequency dynamic LFE sound effects accentuate problematic room resonances only at those discrete frequencies. Acoustic damping can help calm excessive 30 to 80hz peaks.
Tower or satellite speakers may distort only when crossing over to sub at certain tracks demanding reduced bass output or a higher crossover point to isolate drivers.

Q: Should I get a bigger better subwoofer if distortion is still happening?

A: If extensive wiring scrutiny, positioning adjustments and acoustic treatment changes fail to reduce distortion from an older entry level sub even when played at moderate volumes, an upgraded model is likely required. Consider one size class larger with higher continuous power amplifiers, larger stiffer driver elements and solid internal bracing. This reduces strain and distortion behavior when played loudly. Apply past troubleshooting lessons!

Q: Where is the best place to put a subwoofer?

A: Starting with corner loaded placements can greatly magnify bass output but often accentuates nasty room resonances causing boomy muddy distortion problems. Move towards room centers and divide sub and seating locations diagonally across opposite corners. Reduced excitation of problematic dimensions helps. Stay at least 18 inches from any single boundary wall or objects.

Q: Can old age deteriorate subwoofer driver components?

A: Yes, decades old subwoofers employing the same daily drivers inevitably accumulate physical deterioration from years of heavy use – worn out suspension surrounds, bent dustcaps, buzzing voice coils and creaky spiders. These aging mechanical issues absolutely contribute to noticeable distortion problems over time needing full replacements. Inspect drivers thoroughly before assuming amps are solely causing problems.

Q: What’s the best way to test if a sub works correctly?

A: Rather than only playing familiar music or movie content with strong but random low end, use consistent repeatable test signals like frequency sweeps and sine wave tones 20 to 80hz. While carefully listening for ragged distortion, walk around multiple seating spots to diagnose excessive room resonances causing variations too. Switch subwoofer location and directionality as well when testing. This helps pinpoint loudest problem room modes.