Best Amp Settings For A Subwoofer

Norvan Martin
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 Truth is, there isn’t a single ideal setting for your sub as it is, not a one-size-fits-all problem. However, you can achieve the best bass output from your sub based on the settings of your amp, the capabilities of your stereo speakers, and the space they are in.

Generally to achieve the best settings for your subwoofer, start by keeping the gain low and setting the low pass filter high. Next, adjust the bass boost to a moderate level or turn it off completely as this will help you cut out unwanted bass frequencies. Finally, adjust the gain of the sub so that it sounds similar in volume to the stereo speakers.

Here is an even quicker way to correctly set your amp for your subwoofer:

  • LPF – ON
  • Frequency 60 Hz
  • Gain – start from 0 and rotate the gain knob clockwise until you feel the sound is too loud or vocals start to appear in the subwoofer output.

In addition, the following settings will also allow your subwoofer to achieve the loudest and most accurate bass:

Subwoofer Low-Pass Filter: 80Hz at 24dB/octave
LCR Main-High Pass Filter: 80Hz at 12dB/octave
Surround High-Pass Filrer: 125Hz at 12dB/octave

Before you get to the specific settings for your amplifier, however, you should first ensure that your amplifier and subwoofer are properly matched. Start by checking the RMS power rating of your subwoofer.

For example, if your subwoofer is rated at 400 watts RMS and 4 ohms, you need to ensure that the amplifier is rated at 4 ohms or higher and the power it can deliver is at least 500 watts. If your amplifier’s power rating is much higher than the sub however, you will need to adjust the gain on the amplifier to limit the amplifier’s output so that you prevent damage due to overpowering the subwoofer.

For more detailed information, below are some easy steps for the best amplifier settings for your subwoofer.

Step 1: Determine The Crossover Frequency

This is the frequency that dictates when the exact point the speakers start to be overtaken by the subwoofer. As the majority of the bass in music and movies is present in the low-frequency range, the crossover frequency is advised to be set at about 75Hz or even lower. This is set for the subwoofer using the low pass filter.

how to set low pass filter on an amp

You can learn more by reading our article on how to set a subwoofer’s crossover frequency.

Step 2: Set The Phase

The time of the subwoofer’s output about the main speakers is controlled by the amplifier’s phase control tool. If the bass sounds from the speaker seem too weak, try setting it to 0 degrees first, and then experiment with switching it to 180 degrees in a gradual process.

If your subwoofer can only be set to 0 or 180 degrees, check out our article on whether to set your subwoofer to phase 0 or 180 in cases where you have a subwoofer switch instead of a dial. You can learn more by reading our article on how to set a subwoofer’s crossover phase. Your subwoofer must not be out of phase.

Step 3: Volume Adjustment

Adjust the subwoofer’s volume so that it blends well with your speakers. While you don’t want the subwoofer to be too quiet, you also don’t want its sounds to drown out the main speaker sound with too much bass

Step 4: Sound Of The Room

Your listening room’s acoustics and arrangement can significantly affect or impact how well or worse your subwoofer can perform. Try several placements to determine where the subwoofer will sound best in your space, and think about applying acoustic fixes to help cut down on glaring reflections and enhance bass response.

Step 5: Consider the Size of Your Room

These factors can have a big influence on the subwoofer’s sound quality. For instance, a bigger subwoofer may be too powerful for a small room and result in distortion. On the other side, a smaller subwoofer may not be capable of providing enough bass in a big space.

Try out various subwoofer sizes and places to see which configuration works best in your environment.

Step 6: Subsonic Filters

This type of filter helps in eliminating extremely low-frequency noise that can cause the subwoofer to distort. Applying a subsonic filter to amplifiers will reduce the deep bass notes in music and movies and also help to remove undesired noise, setting the subsonic filter at a frequency of around 17-22 Hz is advised.

Step 7: Gain Control

This is used to modify the input signal level that the amplifier receives from the source device. A subwoofer that has its gain set too high may become distorted. To prevent this, start with the gain set to the lowest setting and raise it gradually until the desired bass level is achieved.

Step 8: The Type of Subwoofer

The amplifier settings will also depend on the type of subwoofer you have. For instance, the frequency response of a sealed subwoofer will be different from that of a ported subwoofer. You should check out your device’s user manual to get the maximum performance out of your specific subwoofer.


What Does An Amplifier Do?

An amplifier is a device that strengthens a weak audio signal so that it can enable the speakers or headphones to generate louder, clearer sound. Some amplifiers allow the user to customize the sound according to their tastes by including features like tone adjustments, equalization, and volume controls in addition to amplifying the audio stream. Home theaters, automobile stereos, subwoofers, and professional sound systems are just a few examples of the many audio systems that require amplifiers. 

Below are a few stages in an amplifier 

The preamp stage of an amplifier is responsible for amplifying audio signals before they reach the main stage. This stage also carries out other tasks like equalization and tone control in addition to controlling the input signal level.

The power amp stage receives the signal after the preamp stage, which amplifies it further and supplies the power required to drive the speakers. One or more transistors or tubes make up the power amp stage, which boosts the voltage and current of the audio stream.

The output stage receives the audio signal after it has been amplified, and it transforms the electrical signal back into audible sound waves.

Do all Subwoofers Need an Amplifier?

Do you want a quick answer? Yes, your subwoofers will require an amplifier. You can’t utilize your sub without an amplifier since it effectively serves as the speaker and power for the subwoofer.

There are a few exceptions, though. Although it’s unusual, some subwoofers come with an amp already installed. In some automobile models, the sound system will already have an amplifier. In this case, you will not need an amplifier.

How To Identify A Subwoofer From An Amplifier?

You might not be familiar with either phrase if you’re not familiar with sound systems.

The cone-shaped components of a loudspeaker that create the bass sound are called subwoofers. Typically, subwoofers are intended to boost the bass of the music, making it louder, richer, and with a frequency that you can feel throughout your entire body.

On the other hand, amplifiers are a distinct gadget from subwoofers. They are a piece of electrical machinery that enhances subwoofer sound. Additionally, they allow you to modify the sound in many aspects, including the sound being filtered through and how much the bass is amplified.


The best amplifier settings for a subwoofer are determined by the capabilities of the stereo speakers and the space they are in.  An amplifier is a device that strengthens a weak audio signal to enable the speakers or headphones to generate louder, clearer sound. It also allows the user to customize the sound according to their tastes.  If you want to get the best settings from your amp and produce a unique sound, follow the steps in this article.

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Norvan Martin is the founder of He is a professional Electronics Engineer and is passionate about home theater systems and AV electronics. BoomSpeaker was created as an online hub to share his knowledge and experiences as it relates to home theaters and home audio electronics. My email: [email protected]  Connect on Pinterest and Linkedin