Adding Subwoofer to PA System: Ultimate Sound Enhancement Guide

Table of Contents

Last Updated on February 13, 2024 by Muisc Pro Editorial Team

Adding a subwoofer to your PA system can significantly enhance its sound quality. Subwoofers are designed to reproduce low frequencies, typically between 30 Hz to 150 Hz, which are essential for achieving a full, rich sound. This range complements the capabilities of standard PA speakers, which can produce a wide range of frequencies but may struggle with the lower end, especially at higher volumes. The inclusion of a subwoofer can transform your audio experience by enhancing bass frequencies and providing the punch needed for kick drum sounds, vital for pa speakers in live performances, particularly in settings like DJ sets or live band performances, by adding volume and delivering the deep, booming bass that energizes the audience.

Integrating a Subwoofer into Your PA System

When adding a subwoofer to your PA system, the first step is to decide between an active or passive subwoofer. Active subwoofers, also known as powered subwoofers, have a built-in power amp, making them ready to use and capable of handling low frequencies efficiently without additional equipment, while passive subwoofers require an external amplifier. Your choice will depend on your complete PA system’s existing components, including the use of a high pass filter to ensure a smooth transition between low frequencies and high pass frequencies for convenience and setup complexity.

Key Features to Consider in a Subwoofer

When selecting a subwoofer for your PA system, several features merit attention, affecting performance and integration ease.

  • Power and Power Handling Capabilities: For both active and passive subwoofers, power (or power handling) is a crucial factor but not a direct indicator of volume. Ideally, a subwoofer should match or exceed the power output of your main speakers to ensure balanced sound reproduction.
  • Speaker Size and Frequency Range: The size of the subwoofer and its frequency range are good indicators of its sound depth and performance capacity. Larger speakers are generally capable of producing lower frequencies, crucial for a full-sounding audio output.
  • Pole Mounts and Casters: Many subwoofers include pole sockets for easy alignment and space-saving speaker mounting. Additionally, casters are invaluable for portable systems or setups that require frequent movement, sparing you from heavy lifting.

Setting Up Connections and Crossovers

Proper integration of a subwoofer involves understanding crossovers and connections. A crossover divides the audio signal into different frequency ranges, directing low frequencies to the powered subwoofer and higher frequencies to the full range speakers, ensuring a complete PA system. Most modern PA systems and subwoofers come with built-in crossovers, simplifying this process. Connecting your subwoofer, especially when using PA speakers to accurately reproduce the kick drum sound, typically involves linking the mixer’s output to the subwoofer’s input, then connecting the subwoofer’s output to your loudspeakers. Alternatively, using an aux send from the mixer to the subwoofer allows for more selective control over which frequencies are sent to the sub, helping to avoid unwanted low-frequency noise in your output.


Connector Types and Input/Output Options: The variety of connectors (XLR, 1/4″, speakON, etc.) and the availability of input/output configurations, such as daisy chaining or stereo summing, are important for system compatibility and setup flexibility. These features facilitate easy integration with existing equipment and adaptability for different sound reinforcement scenarios.

The Importance of Crossover and DSP: Powered subwoofers, equipped with a power amp, usually come with built-in active crossovers, essential for directing bass frequencies efficiently between the subwoofer and PA speakers, which are essential for directing frequencies efficiently between the subwoofer and main speakers. An adjustable crossover frequency is beneficial for fine-tuning your system’s sound. Additionally, some subwoofers feature DSP (Digital Signal Processing) for advanced integration and tuning options, optimizing the power alley in a complete PA system for enhanced listening experiences in different sound reinforcement scenarios, enhancing the overall performance when combined with complex systems. DSP capabilities may include extra tuning options, remote control, and better alignment with main speakers, offering a higher level of customization and control over your sound.

Enhancing Sound Quality Through Filtering

To achieve a seamless audio experience, filtering plays a crucial role in managing frequencies between your subwoofer and loudspeakers. Subwoofers often feature filtering options like “through” and “high pass filter” (HPF), which determine how frequencies are distributed. Using a high pass filter, part of the crossover network, ensures that only frequencies above the crossover point are sent to the loudspeakers and floor monitors, creating a smooth transition between full range speakers and passive subs, which can conserve energy and reduce distortion. This not only makes your system more efficient but also enhances the overall sound quality by limiting intermodulation distortion (IMD) that can occur when a wide range of frequencies is produced by the same speaker.

Gaining More Control Over Your System

Modern subwoofers offer various controls that allow for fine-tuning of the system’s audio response. Features like a “level” knob let you adjust the output of the subwoofer to match the main speakers or to suit the specific environment. Additionally, some subwoofers offer a “cardioid” setting, which optimizes bass directionality, focusing the sound towards the audience and away from the stage. This is particularly useful for live performances. Other subwoofers may include a phase inversion setting, which can enhance low-frequency response by adjusting the phase of the bass. These controls provide the flexibility to customize your PA system’s sound to meet the needs of any event or venue, ensuring the best possible audio experience for both performers and audiences.

Exploring Subwoofer Options for Your PA System

Subwoofers, an essential component of a PA system, are categorized into active (powered) and passive (unpowered) types, each with unique features and benefits that cater to different setup needs.

Active/Powered Subwoofers

Active subwoofers incorporate built-in amplifiers, simplifying the setup process by eliminating the need for external power amps. This integration not only makes them convenient but also includes active crossover circuits that allow for direct connection from the mixing board, routing high-passed signals to the rest of the PA system. Though active subs may be heavier and slightly more expensive due to their added electronics, the convenience and reduced need for additional equipment often justify the cost.

Passive/Unpowered Subwoofers

Passive subwoofers, characterized by their simplicity, typically consist of a low-frequency driver and may include an induction circuit for frequency rolloff. They are lighter and more affordable but require an external amplifier and, in most cases, a crossover for optimal integration into a PA system. This necessitates additional investment, making them suitable for setups where customization and specific amplifier pairing are preferred.


In conclusion, incorporating a subwoofer into your PA system can dramatically improve the depth and quality of sound, providing a richer and more immersive audio experience. Whether you opt for an active subwoofer for its convenience and integrated features or a passive subwoofer for its flexibility and customization potential, understanding the key features such as power handling, speaker size, connectivity options, and advanced controls like DSP and crossovers is crucial. By carefully selecting a subwoofer that matches your system’s requirements and preferences, you can enhance your live sound setup, ensuring powerful, clear bass that resonates well with your audience. Remember, the right subwoofer not only complements your existing PA system but also elevates the overall performance, making every event memorable.


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