That moment when you buy a shiny new subwoofer, bring it home, and fire it up for the first time, only to be disappointed by its lackluster performance. And then you wonder, “Why does my subwoofer sound weak?” If this has happened to you, don’t despair! In most cases, a few simple fixes can get your subwoofer sounding as good as you expected.
Before you go back to the electronics store, let’s look at some common reasons why subwoofers sound weak and how to fix them.
What is a subwoofer again?
Before explaining why your subwoofer might sound weak, let’s define what a subwoofer is and does. Trust me. It’s going to be important later. A subwoofer is a loudspeaker reproducing low-frequency audio signals, typically below 200 Hz. The primary purpose of a subwoofer is to supplement the low-frequency response of full-range speakers, which are not designed to reproduce very low frequencies.
There are two main types of subwoofers: active and passive. Active subwoofers have built-in amplifiers, while passive subwoofers rely on an external amplifier to power them. You can typically recognize a subwoofer in your sound system by its large size. This is because low-frequency sounds require a larger speaker cone to produce than high-frequency sounds.
Why does my subwoofer sound weak? 9 most common reasons
Now that we know what a subwoofer is, let’s look at some common reasons why the sound might be weak.
1. Lowered Bass Level
A common reason a subwoofer sounds weak is that the bass level has been turned down or muted. If you never had a subwoofer before, you might have moved the bass-level knob without realizing it. After all, the difference wasn’t noticeable until you added a subwoofer to the mix.
Turn up the bass level until you achieve the desired sound to fix this. If you’re using an AV receiver, there might be a dedicated subwoofer knob or level control that you can adjust. Otherwise, look for a general bass-level setting in your home theater or surround sound system.
2. Incorrect speaker settings
Not a common problem unless you can select the crossover frequency in your sound system. The crossover frequency is the point at which your subwoofer will start reproducing sound. For example, if your crossover frequency is set to 100 Hz, all frequencies below 100 Hz will be sent to your subwoofer, and all frequencies above 100 Hz will go to your main speakers.
If the crossover frequency is too low, you might not get enough bass from your main speakers. Conversely, if the crossover frequency is too high, your subwoofer might not get enough low-frequency information to reproduce.
If this information is too technical or you don’t see any “crossover” knob in your sound system, you can skip this issue as it only applies to advanced sound setups.
3. No low-frequency output
This is a technical way to say that your music doesn’t have enough bass. If you’re playing music with little or no low-frequency content (e.g., classical music), there’s not much your subwoofer can do to reproduce sound.
One way to solve this problem is to find music specifically mixed for subwoofers, such as some EDM (electronic dance music) tracks. These songs are designed to have a lot of low-frequency content and make your subwoofer sound its best.
If you don’t want to listen to EDM, try adjusting the EQ settings in your music player. Boosting the bass frequencies will give your subwoofer something to work with and might make a noticeable difference, but don’t overdo it, or your music will sound muddy.
4. Wrong equalizer settings
Equalization, or EQ, is adjusting the balance of frequencies in an audio signal. For example, you can use EQ to boost the bass frequencies in a song that doesn’t have enough low-end.
If your subwoofer sounds weak, try adjusting the EQ settings in your music player or AV receiver. If you don’t see any EQ settings, look for a “Bass Boost” or “Loudness” setting. Boosting the bass frequencies will give your subwoofer something to work with and might make a noticeable difference. Still, if you’re not an expert, using one of the recommended equalizer settings for the music genre you’re listening to is more manageable.
5. Underpowered subwoofer
Another common reason for a subwoofer to sound weak is that it’s not getting enough power. This usually isn’t a problem if you have an active subwoofer (one with its built-in amplifier and AC connection). However, if you have a passive subwoofer, it must be powered by an external amplifier. If you’re building your sound system with separate components, ensure the subwoofer amplifier has enough power to drive your subwoofer.
If your subwoofer is underpowered, the sound will be weak and lack impact. If you’re using a receiver or amplifier, ensure it has enough power to drive your subwoofer. A good rule of thumb is that your amp should be able to deliver at least twice the power of your subwoofer’s RMS rating.
6. Wrong connection
This is another common mistake when setting up their home theater or surround sound system. If you’re not getting any sound from your subwoofer, ensure it’s properly connected to your receiver or amplifier.
Sometimes people connect the subwoofer to the wrong output on their receiver. For example, if you’re using a 5.1 surround sound system, you’ll need to plug the subwoofer into the “Subwoofer Out” port on the back of your receiver, but maybe you connected it to the “rear” or “center” channels, and that’s why it’s not working.
When you’re building a sound system and mixing different brands and components, it’s not uncommon for the connections to be a little confusing. If you’re unsure which output to use, consult the owner’s manual for your receiver or amplifier.
7. Poor acoustics
If you place your subwoofer in a poor location or there are obstacles, this can cause sound waves to cancel each other out and weaken the bass response. Make sure your subwoofer has enough space to breathe and isn’t placed behind a piece of furniture.
The best place for a subwoofer is usually in the corner of the room, but this isn’t always possible or practical. Experiment with different locations and see what sounds best in your room. If you can’t get a good bass response no matter where you put your subwoofer, try adding acoustic treatment to your room (e.g., bass traps, absorbers, or diffusers).
8. Blown subwoofer
If your subwoofer suddenly stops working or the sound is distorted, the driver (the speaker’s part producing sound) may be blown. This issue can happen if you play your subwoofer too loud or if there’s a power surge. Sometimes there’s a rattle noise when the bass kicks in, which signifies that the subwoofer is damaged.
If you think your subwoofer is blown, take it to a repair shop and have them check it out. Depending on the damage’s extent, replacing the subwoofer might be cheaper than having it repaired.
9. Improper polarization
Finally, this is a less common problem, but it’s still worth mentioning. Subwoofers need to have the correct polarity relative to the other speakers in your system. This means that the subwoofer’s “+” terminal needs to connect to the amplifier’s or receiver’s “+” terminal, and the “-” terminals need to attach to the negative poles.
If the subwoofer is reverse-polarized (i.e., the “+” and “-” terminals are swapped), the sound will be weaker because the bass frequencies will cancel each other out. If you’re unsure whether your subwoofer is polarized correctly, consult the owner’s manual or take it to a professional for help.
Again, this isn’t very common, but if you see multiple connections with +/- symbols next to them, make sure they’re correctly aligned.
Why does my subwoofer sound weak? The bottom line
There you have it! These are the main reasons why subwoofers can sound weak. If you’re experiencing this problem, go through this list and see if you can find the root cause. In most cases, it’s a simple mistake that can be easily fixed.
If you have any other questions about setting up your home theater or surround sound system, please post them in the comments below! Did you ever have a problem with your subwoofer sounding weak? How did you fix it? Let us know in the comments!