Tracking New Trends and Applications in Waveguide Technology
Live sound audio systems are continually evolving to meet higher expectations from audiences regarding sound quality and from engineering crews seeking performance, efficiency and fidelity. Waveguide technology has emerged as a crucial area of innovation, and recent advancements, such as QSC’s new LEAF™ (Length-Equalized Acoustic Flares) technology, are setting new benchmarks for what waveguides can achieve.
Though often hidden behind speaker grilles, waveguides play a vital role in shaping sound waves and ensuring consistent coverage across venues of all sizes. A waveguide is an acoustic component that directs high-frequency sound waves from compression drivers into a controlled, purposeful wavefront. It also serves as an acoustic impedance adapter, bridging the high impedance at the driver’s exit with the much lower impedance of the surrounding air.
The result? Louder, clearer high-frequency output and the ability to manage how sound spreads across an audience. Waveguides are also crucial in determining crossover points between high- and low-frequency drivers, directly affecting a system’s clarity and phase alignment.
Legacy Challenges in Waveguide Design
Despite their widespread use for several decades, designers of traditional waveguides have long struggled with a handful of persistent issues:
- Inconsistent Wavefront Flatness, leading to uneven sound dispersion and poor coupling with adjacent loudspeakers, particularly at the highest audible frequencies.
- Bulky Physical Depth, particularly when adding a horn-type flare to shape sound in multiple directions.
- High Crossover Points, resulting in low-frequency lobing and phase-related coverage issues between low and high drivers around the crossover frequency.
- Low Sensitivity, requiring more powerful (and typically more expensive) compression drivers and amplifiers to achieve desired output levels.
- Resonance and Sound Coloration, creating distortion or “ringing” that compromises audio fidelity.
Enter QSC LEAF: A Game-Changer in Acoustic Design
The QSC LEAF Waveguide is designed to deliver the performance of larger waveguides in a more compact form, as employed in QSC’s recent LA108 and LA112 line array designs. LEAF technology originated from the need for smaller, efficient waveguides capable of producing the same acoustic quality as their larger counterparts.
Protected under U.S. patents US 11,509,997 B2, US 11736859B2 and US 12075209B2, QSC’s LEAF technology introduces a revolutionary approach to waveguide design. LEAF addresses the major shortcomings that have plagued earlier designs by optimizing the geometry and functionality of internal wave paths.
LEAF is based on a two-part structure. One part is a “Path Equalization” section designed to be as shallow as possible, enabling a greater reduction in physical depth while ensuring phase alignment at the waveguide exit. This guarantees a flat wavefront, with the capability to tailor the flare shape and depth for optimal performance across diverse applications. Consequently, LEAF can be utilized in more physically confined applications than any waveguide that has come before, such as in QSC’s KC12 “K Column” loudspeakers.
The second part is a “Flares” section, where each channel expands in two simultaneous directions, creating what QSC calls “mini-horns.” This approach allows for maximum wavefront shaping and optimal impedance matching with the surrounding air, resulting in greatly improved sensitivity, smoother frequency response and lower possible crossover points.
This structure contrasts with the two-step expansion found in many traditional models, which often limit wavefront control and sensitivity performance, especially around the crossover frequency, while still requiring a much larger package.
Real-World Gains: Performance Comparisons
In live sound applications, Waveguide technology manages the dispersion of sound waves, enhancing clarity, coverage and directionality. It can provide uniform sound distribution across large venues, reduce feedback, ensure precise targeting of sound and improve intelligibility in reverberant spaces. Its design is critical for tailoring the sound field, particularly in challenging acoustic environments or large-format live events.
QSC’s LEAF-enabled loudspeakers, such as the LA108 and LA112 models, have demonstrated tangible advantages over competitors:
- Lower Crossover Points: As low as 1,300 Hz, compared to 2,000+ Hz in similar products. Future LEAF-enabled loudspeakers could feature even lower crossover points.
- Greater Sensitivity: Broadband sensitivity advantage, with 6+ dB more output at certain critical frequencies when using the same compression drivers.
- Flatter Wavefronts: Resulting in more uniform coverage and superior coupling with adjacent array loudspeakers, especially at the highest frequencies.
- Reduced Resonance: Less coloration and distortion of sound.
- Compact Design: Superior performance without the bulk and the ability to bring waveguide technology into more space-constrained products than ever before.
LEAF-equipped models excel in nearly every key audio metric compared to competing products.
Feedback from artists and sound designers has been crucial in refining the LEAF waveguide, ensuring it meets the real-world needs of its users. The collaboration between engineers and artists helps hone the acoustic components and add that final touch of audio excellence, often described as “secret sauce.” This partnership ensures that the final products deliver superior sound quality and align with the expectations and needs of performers.
The LEAF waveguide’s adaptability is evident by its integration into various QSC products, from high-end line arrays to portable speakers for mobile DJs and singer-songwriters. This versatility is largely due to the innovative use of computer simulations and 3D printing in its development, which has significantly reduced the need for physical prototypes and accelerated the design process. These tools make precise planning and adjustments easier, ensuring that each waveguide is finely tuned for its specific application.
Where Waveguides Go Next
With the introduction of LEAF, the industry is moving towards intelligent acoustic engineering, where compact form factors, precision coverage, and high output are no longer mutually exclusive. Advances in waveguide design will continue to shape the development of line arrays and portable systems, particularly in high-demand settings like touring, fixed installations and immersive audio systems.
The LEAF waveguide is set to evolve alongside other advances in audio engineering, adapting to new demands and technologies in the industry. This evolution is driven by the waveguide’s inherent flexibility and the ongoing improvements in simulation and manufacturing techniques.
Keeping pace with the ongoing progression of audio technology, the LEAF waveguide will likely continue to see enhancements in its design precision and efficiency. The ongoing development of computer simulations will enable even more intricate modeling of sound waves, allowing engineers to push the boundaries of compactness and acoustic performance. This means future versions of the LEAF waveguide could achieve even greater sound clarity and projection while maintaining a small footprint.
The integration of artificial intelligence and machine learning in audio engineering has the potential to revolutionize how waveguides are designed and optimized. AI could analyze vast amounts of acoustic data to identify patterns and suggest design modifications that may be less obvious to human designers. This would enable the creation of waveguides tailored to specific applications, dynamically adapting to different environments and usage scenarios.
As the demand for high-quality audio in various settings grows, the LEAF waveguide could be tailored for a wider range of products, from ultra-portable devices to sophisticated sound systems for large-scale events. The ability to customize the waveguide design for specific acoustic environments means it could find its way into more niche markets, catering to the unique needs of each segment.
Audio manufacturers will continue to push the boundaries of what is possible in live sound applications. Led by companies like QSC, waveguide development will strengthen the technology as a critical enabler of high-performance sound systems.
For more info, visit www.qsc.com.
David Fuller is the vice-president of engineering and product management at QSC Audio
