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Beamforming refers to a “beam-shaping” technique based on digital signal processing that allows precise control over the direction of sound propagation. This is achieved by using multiple transducers microphones or loudspeakers arranged in an array to generate a sound beam that can be steered and shaped. The goal is to concentrate the sound in a specific direction, minimize noise from unwanted sources, and enhance speech intelligibility in noisy or reverberant environments. In this article, we will explore the subject with a particular focus on its implementation in the loudspeakers of our partner Harmonic Design.
The ability to control the dispersion pattern of loudspeakers that is, the way sound propagates through space from the source has always fascinated electroacoustic researchers and sound engineers. Before the advent of digital technology, however, the topic was rather difficult to address due to the inherent limitations of analog systems. In fact, beamforming has been around for decades, though primarily in fields outside acoustics (notably in radio frequency), where it was first applied in military applications as far back as World War II.
In professional audio, the first practical applications appeared roughly a decade ago, aimed at solving long-standing issues in sound reinforcement, especially in enclosed or acoustically challenging environments.
How does beamforming work and what problems does it solve?
The core principle behind this technology is phase delay and the summation of signals emitted by the array’s loudspeakers. By applying specific time delays to the signals fed into each transducer, the combined emissions reinforce one another in the desired direction while canceling out in others. This can be implemented in both the time and frequency domains.
Beamforming can be considered a more advanced version of beamsteering, a technique used in acoustics to control the direction of sound radiation from a loudspeaker array without physically tilting the cabinets. Through DSP, beamsteering creates a directed lobe of sound aimed at a target zone. However, unlike beamforming, it does not allow the creation of multiple independent beams, suppression of unwanted side lobes, or such precise control over the resulting polar pattern.
By enabling one or more beams to be directed precisely where needed, beamforming techniques provide several key benefits:
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Improved speech intelligibility in reverberant environments such as churches, houses of worship, or large indoor venues with untreated surfaces. These spaces typically feature vast volumes, high ceilings, irregular surfaces, and hard, reflective materials such as stone, marble, or glass—all of which contribute to excessive reverberation that makes speech difficult to understand, particularly when sound comes from multiple sources.
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Reduced sound dispersion into irrelevant zones, ensuring energy is not wasted where it is unnecessary.
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Frequency-independent beamwidth. Unlike conventional line arrays, which become more directional as frequency increases (resulting in a wide low-frequency lobe and a narrow high-frequency one), Harmonic Design’s beamforming systems maintain controlled vertical dispersion across the spectrum.
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Cleaner, more discreet installations. Loudspeakers can remain fixed and partially concealed, while digital signal processing makes it possible to redirect beams as needed.
Harmonic Design’s beamforming technology
Introduced in 2016, Harmonic Design’s beamforming technology enables precise shaping of the loudspeakers’ polar response, focusing sound exclusively in the areas where it is truly needed.
The HD Beam series column loudspeakers feature ultra-slim cabinets just 80 mm wide making them virtually invisible in permanent installations and the narrowest beamforming-based models available on the market. Their elegant powder-coated aluminum housing and fine steel grille allow them to blend seamlessly into any architectural setting. Using a series of full-range drivers, they avoid phase shifts between frequencies and deliver wide, uniform horizontal coverage. The catalog includes eight models, equipped with 8, 16, 24, or 32 transducers (2” or 3” depending on the model) in array configuration.
To tailor each loudspeaker to its specific location, a preliminary simulation is required to adjust beam parameters. For this reason, Harmonic Design’s hd LevelZ remote software includes a comprehensive simulation tool. This allows the user to set parameters such as room height, depth, and positioning, and to preview the 2D beam pattern and SPL plots at various frequencies until the optimal configuration is achieved.
From a technical standpoint, Harmonic Design’s beamforming allows control of the vertical emission lobe within ±60° in 0.1° increments and the creation of up to four separate main beams. Horizontal dispersion is constant at approximately 100°.
Additionally, the proprietary ADO (Advanced Directivity Optimization) algorithm suppresses unwanted side lobes, further enhancing speech clarity even in highly reverberant environments.
Here are some examples of beam steering at selected angles:
Beam at 0°
Beam at -7°
Multiple beam at +5° / -23°
This technology integrates seamlessly with the Dante protocol for digital audio-over-IP transmission and supports modular configurations of up to 32 DSP/amplifier channels, making the loudspeakers highly scalable and customizable to specific reinforcement needs.
Looking ahead
The future of beamforming in professional audio is set to be transformative, with increasingly sophisticated applications in fixed installations, theaters, stadiums, and houses of worship, as well as in touring even if, for now, the latter sector has less demand.
With DSPs becoming more powerful and costs continuing to drop, beamforming systems are steadily becoming more accessible and scalable.
Looking forward, we can expect greater integration with protocols such as Dante for audio-over-IP transmission, alongside advanced customization through acoustic simulation and remote-control software. Beamforming will, in essence, become increasingly “intelligent,” dynamically adapting to environments and audiences, paving the way for tailored immersive sound experiences.
Want to learn more?
Email us at international@audioeffetti.it
