Last Updated on February 16, 2024 by Muisc Pro Editorial Team
Public Address (PA) systems have evolved significantly over the years, leading to the development of two primary types of sound system designs: single point source and multiple point source. Each design offers unique advantages and challenges, which are crucial to understand when setting up a PA system.
When setting up a PA system, choosing the right kind of speaker is crucial. This decision should be based on several key considerations, including the size and shape of the area that needs sound coverage, the type of music the system will support, and the system’s gain before feedback (GBF). Other factors include the architectural design of the space, which might necessitate focusing sound away from reflective surfaces, as well as aesthetic concerns and sightlines. These elements collectively determine the most suitable speaker type for a given environment, whether it be a line array system or a point source system.
The Basics of Multi-Point Source Systems
Multi-point source systems emerged from the need for very high output power. This concept allows for the distribution of sound through multiple components, aiming to increase the volume and coverage of audio output. Initially, multi-point sources consisted of numerous cabinets stacked together, intended to project sound in all directions. Despite their high output, these systems often suffered from significant drawbacks, including the suppression of high-frequency sounds and time-shifted outputs, leading to a poor system impulse response. The evolution of multi-point systems saw the introduction of one-axis systems, which offered improved frequency response and clarity over their predecessors.
Point Source Speakers
Point source speakers, also known as “point-and-shoot” or “traditional” speakers, are common in various settings. They are typically rectangular and designed to cover specific vertical and horizontal angles thanks to their horn configurations. These loudspeaker systems can be used individually or as part of a larger array vs. single point, offering flexibility in deployment and the ability to provide precise aiming for overall sound coverage.
Advantages
- Versatile in use, suitable for various room sizes, aesthetics, and budgets.
- Available in multiple sizes; smaller models are portable and easily repositionable.
- Can be concealed without compromising sound quality, blending practicality with aesthetics.
- Provide effective pattern coverage; size and shape of the horn enhance mid and high-frequency control.
- Larger horns improve pattern control, making them ideal for small to medium-sized rooms.
- Capable of controlling both horizontal and vertical sound coverage.
- Offer advantages over line arrays and column speakers in certain environments.
- More cost-effective than line arrays, due to fewer enclosures and components per unit.
Disadvantages
- Limited low-frequency pattern control compared to line array systems.
- Generally shorter in height, affecting their ability to control low frequencies.
- Arraying challenges require skill to prevent acoustic lobing and interference at cabinet seams.
- “Long-throw/short-throw” configurations may cause interference without careful design.
- Insufficient throw distance for deeper spaces, potentially requiring delay speakers.
- Delay speakers can introduce sound quality inconsistencies across the listening area.
- Clarity in the front area may be affected by interference from delay speaker frequencies.
Vertical Line Arrays
Vertical line arrays represent a modern solution in sound reinforcement, particularly visible in large concert environments. These systems consist of line array speakers, each equipped with several drivers, arranged vertically and often forming a long J-shaped configuration on both sides of the stage. Over the last decade, their adoption in large venues has surged, thanks to the unique benefits they offer in sound distribution and quality, distinguishing them from point source loudspeakers and column arrays.
Advantages
- Maintain consistent sound levels across the listening area, from front to back.
- Uniformity achieved by adjusting physical angles and amplitudes of individual modules.
- Direct sound efficiently to the rear, ensuring a uniform audio experience for the audience.
- Excel in controlling vertical spread of low frequencies, reducing unwanted sound reflection from ceilings and leakage onto the stage.
- Minimize feedback from open microphones, enhancing sound clarity and gain before feedback (GBF).
- Notable sound pressure level (SPL) capability, with multiple drivers producing a coherent wavefront of sound.
- Often exceed required SPL, making them suitable for high sound reinforcement needs.
- Allow the system to operate below its maximum stress point, ensuring better longevity and performance.
Disadvantages
- Vertical orientation may not suit shallow rooms, as design is optimized for longer distances.
- Difficulty in matching coverage needs for horizontally oriented spaces.
- Effective deployment requires sufficient vertical height for desired pattern control.
- Lack of height can lead to sound reflection issues off ceilings and stages, reducing sound quality and increasing feedback.
- Potential sightline obstruction, affecting audience view of the stage or video screens.
- Significant cost due to the large number of modules and drivers required, posing a financial challenge.
Column Array Speakers
Column array speakers, known for their sleek design and vertical driver arrangement, offer a unique solution for sound reinforcement, similar to their counterpart, the line array. These speakers combine multiple drivers within a single, narrow cabinet, making them a visually appealing option for various spaces, including houses of worship and contemporary venues.
Since their inception in the mid-20th century, column speakers have seen fluctuating levels of popularity. Initially favored for their pattern control in large, reverberant spaces like cathedrals, they experienced a decline in use before recently regaining popularity. This resurgence is attributed to technological advancements and improved performance capabilities, extending their use into more modern worship spaces and beyond. Column speakers come in two main varieties: passive and powered, each with its own set of benefits and potential drawbacks.
Advantages
- Aesthetic compatibility with both traditional and modern environments.
- Slender design for discreet integration, often mounted near architectural features with minimal disruption.
- Passive column speakers offer cost-effective vertical pattern control.
- Recent passive technology allows for adjustable coverage patterns and extended bass response.
- Powered column speakers enable electronic coverage adjustment for precise sound aiming.
- Enhanced speech intelligibility and music clarity through precise control.
- Deliver consistent sound levels across the listening space without multiple enclosures.
- Affordability due to the simplicity of a single enclosure and reduced amplification needs.
Disadvantages
- Passive column speakers require physical aiming, potentially clashing with aesthetic preferences due to visible tilt.
- Generally produce lower volume levels and less bass output compared to full-size vertical line arrays.
- Possibility to enhance bass output by adding subwoofers to the system.
- Less effective in controlling horizontal sound patterns compared to point source speakers.
- Particularly challenged in providing effective coverage in shallow rooms.
Conclusion
In the debate between line array and point source speakers, each system offers distinct advantages and challenges that must be carefully considered in the context of the specific needs of a venue or event. Line arrays provide exceptional vertical sound dispersion and consistency over large distances, making them ideal for bigger venues or outdoor spaces. On the other hand, point source speakers offer versatility, ease of setup, and cost-effectiveness, with a performance that excels in smaller to medium-sized environments. The choice between line array and point source systems ultimately depends on factors such as the size of the space, the architectural characteristics, the type of event, and budget constraints. By understanding the unique attributes and limitations of each speaker type, sound engineers and event organizers can make informed decisions to ensure high-quality sound coverage and audience satisfaction.