In live sound, delivering exceptional clarity and even coverage is essential to meeting audience expectations and ensuring the artist’s vision is faithfully represented. Yet, for a long time, there have been accepted shortcomings in trying to achieve this with conventional sound technology. Here at HOLOPLOT, we’ve redefined how live sound can be delivered and controlled, using pioneering technology to overcome traditional limitations and set a new benchmark for audio quality and precision that benefits sound designs in any environment, including live settings. Our Matrix Array systems achieve a more even coverage across the entire audience area by precisely steering and shaping sound, a feature that helps to improve levels and clarity, which in turn allows for a widening of the so-called ‘sweet spot’.
As live event spaces become larger and more acoustically complex, the pitfalls of conventional audio solutions have become more evident. Traditional systems rely heavily on volume to reach distant areas, which often results in an unbalanced listening experience. Audience members close to the stage are subjected to high sound pressure levels (SPLs), while those farther back receive unintelligible sound due to excessive room excitation or the loss of level over distance.
Invented in the 1930s, stereo is still the go-to sound reproduction method for theaters and live performance spaces alike where the focus point is a frontal, centrally positioned stage. But true stereo imaging is only achievable within the so called ‘sweet spot’. This is due to the psychoacoustic phenomenon of the phantom centre. This phenomenon lets a sound source appear to emanate from a point between two speakers in a stereo configuration and is subject to the same sound arriving at both ears simultaneously and with the same intensity. The use of level panning then allows you to position a sound within the stereo image. Anyone not positioned in the sweet spot in the middle of a venue perceives the audio as coming from the loudspeaker closest to them. This causes a disconnect between what we see and what we hear.
With increased awareness around Sound Quality and Sound Control and driven by audience expectations set by high standards of headphones and home cinema technology, there’s been a push to address these limitations. At HOLOPLOT, we’re at the forefront of this evolution, providing tools and techniques that allow sound to be steered, controlled, and optimized in unprecedented ways.
Historically, high SPL levels were assumed to equate to better sound coverage. To ensure clear audio at the rear of such a venue, engineers have to tackle the well known rule of loss of level of 6dB/doubling of distance for a point source or 3dB/doubling of distance for a line source. With conventional systems this means that they’re often driven at extremely high SPL levels at the front to ensure enough level reaches the back. This results in uncomfortable loudness for those closest to the stage. Additionally, reflections and echoes in large spaces make it difficult to achieve uniform coverage, impacting sound quality and audience satisfaction.
This approach heavily sacrifices intelligibility and creates fatigue for listeners. Audiences in turn often assume that if they can’t understand the lyrics, it must be because the system isn’t loud enough and not because there’s a lack of intelligibility.
Achieving intelligibility is not simply a matter of increasing volume; rather, it requires careful control over the direct-to-reverberant sound ratio, the background noise level, and how sound behaves over distance.
Our technology revolutionizes this approach. With our unique optimization algorithms and multi-beam capabilities, we’re able to control sound not only in the vertical but also in the horizontal axis, allowing us to achieve a consistent SPL level from the front to the back of the venue, even across large distances. Engineers can mix sound for the ideal level at front of house (FOH) without worrying about whether it will be too quiet at the back. This ability to precisely control SPL levels across the venue not only enhances audience experience but also adheres to WHO sound level guidelines, ensuring a safer listening environment for all.
It’s not possible to extend true stereo imaging outside of the natural sweet spot. This applies to any left/right audio deployment. If, however, it can be achieved that the sound level of the left and right array does not change with proximity, you can extend the stereo sweet spot. Our Matrix Arrays generate a much more even coverage thanks to proprietary compensation algorithms that compensate for level loss over distance. This allows us to expand the zone in which both arrays can be perceived at the same intensity, maintaining the integrity of the stereo mix.
This concept works for venues and audiences of small to medium size. Once audience sizes increase, the imaging naturally suffers. For conventional systems, this means mixing engineers resort to mixing in mono, and audiences usually perceive that mix from the sound source closest to them. Additionally, ‘spill’ from the neighboring array interferes with the mix, contributing to a less natural listening experience.
A HOLOPLOT system addresses larger audience sizes differently. When a system is scaled up, the beam opening angles need to be widened to cover every seat in the house. But if we continue increasing the horizontal beam width, we run into problems with the arrival times for off-center listening positions.
To mitigate this, we taper the beams to reduce the problems of arrival times, limiting the beam opening angles to becoming too great. Where these issues are the most prominent (closest to the stage) front fills are deployed using a downmix of both main arrays to reduce the problem of extreme steering angles, arrival times, and loss of uncontrolled high frequencies as you get closer to being off-axis to the beam.
If an audience area is so large that the distance between two hangs of Matrix Arrays on either side of a stage is too great, causing echoes due to the delayed arrival time of the sound from the left and right sources, splitting up the coverage zone keeps the signals from each array separate, minimizing ‘cross-talk’ for dual mono use, significantly bettering clarity and intelligibility.
3D Audio-Beamforming lets you define target zones to mitigate loss in audio imaging caused by extremely large coverage areas. By dividing the coverage area into zones we prevent unaligned arrival times of the beams from the left and right arrays. Using defined zones at the front and to the extreme sides of the coverage area we’re able to taper the gain to ensure that outside of the alignment zone (within 50ms), the audience will only experience a mono summed mix, resulting in clear, echo-free sound. This is a feature unique to HOLOPLOT and can only be achieved using 3D Audio-Beamforming.
To help make the decision when zoning is the appropriate approach as opposed to the beams from both arrays being able to naturally reach every seat, we look to the laws of the Haas effect. It dictates that if the arrival times of sounds from two audio sources differ by less than 50 ms, equating to approximately 17m, they are perceived as a single auditory event. This is regularly exceeded with stages getting wider to accommodate large scale productions, meaning that if the difference exceeds 50 ms, they are perceived as separate events. A difference greater than 50 ms results in a clearly audible echo, especially in close proximity to the stage so zoning should be considered to prevent this.
Using HOLOPLOT simulation tools, anticipated delay spread across the audience zone can be assessed. The results of the simulation dictate where problematic times of arrival are likely to occur. This then informs where the audience area should be divided into sections to allow for better control of the level and the mix that goes to these zones.
With live sound, protecting equipment and preserving audio quality are paramount. Our products have different built-in limiter structures for sub HF and LF drivers. For our products, this means 81 and 96 separate driver limiters respectively, ensuring safe operation. The limiters are designed so they reduce any audible distortion to guarantee the highest sound quality.
On a system level this can be monitored via our HOLOPLOT Control software which includes metering functionality for each pass band within the modules or arrays respectively. Blown drivers have always been a prominent service issue in our industry. Our products prevent being driven too hard, ensuring the longevity of the products.
At HOLOPLOT, we’re dedicated to advancing the possibilities of Sound Control in live environments. By combining precision sound steering, consistent coverage, and advanced beam optimization, we provide engineers and artists with unprecedented tools to create the best audio experiences.
Matrix Array systems redefine what live sound can achieve. With the ability to precisely control sound propagation, optimize clarity, and eliminate limitations of narrow sweet spots, we’re ushering in a new era of live sound. For artists, engineers, and audiences alike, this means more than just clear, consistent audio - it means an experience that’s as close to the artist’s intent as possible, every time.