Transparent Sound LED Screens: Leading the New Wave of Digital Cinema

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On 02/27/2025

With the continuous advancements in LED display technology, LED cinema screens have gained widespread recognition for their superior display performance and energy efficiency. Applications of these screens are becoming increasingly common worldwide. However, traditional LED cinema screens often use a fully enclosed box structure, which lacks sound transparency. This design limits the ability to place speakers behind the screen, leading to a misalignment between the sound and image. As a result, the audio quality may not fully align with the on-screen action, limiting the cinematic experience. The introduction of transparent sound LED screens effectively solves this issue, providing better alignment between sound and image, and promises to lead the future of digital cinema.

Table of Contents

What Are Transparent Sound LED Screens?

A Transparent Sound LED screen, also known as an LED sound-transparent cinema screen, is a type of LED display with a specialized perforated structure that allows sound to pass through. This design enables the sound source to align directly with the on-screen action, improving the overall audio-visual experience for viewers.

These screens are a fusion of traditional LED cinema screens and sound-transparent technologies. They offer the visual excellence of conventional LED screens combined with exceptional sound reproduction quality, ensuring that both the display and the audio are optimized for a truly immersive cinema experience.

How Transparent Sound LED Screens Work

Transparent Sound LED screens operate through two primary methods: perforated structure LED screens and acoustic LED screens.

Perforated Structure LED Screens: These screens feature a unique design with small, strategically placed holes in the screen material. The size, shape, and distribution of these holes allow sound waves to pass through while maintaining the integrity of the visual display. This enables speakers to be placed behind the screen, achieving a seamless alignment between the audio and the visuals.

Acoustic LED Screens: In contrast to perforated designs, acoustic LED screens integrate speakers directly into the LED structure itself. This technology is still in the research and development phase and has not yet seen widespread commercial use. Unlike traditional transparent screens, acoustic LED screens aim to create sound directly from the display surface itself, without needing perforations for sound passage.

Key Technical Requirements for Transparent Sound LED Screens

To achieve the same high-quality audio as traditional cinema screens, the position of the primary speakers must align with the rear of the screen, ensuring the sound comes from the correct location relative to the on-screen action. This requires a high level of sound transparency from the LED screen, meaning it must allow sound waves to pass through without significant distortion.

Measuring Sound Transparency: The sound transparency of an LED screen is typically measured using a parameter called “sound attenuation,” which compares the sound pressure levels before and after passing through the transparent structure. The lower the attenuation, the better the sound is transmitted through the screen.

Standards such as JB/T 7809-2005 (Projection Screen Characteristics and Measurement Methods) stipulate that the difference in sound attenuation between 8000Hz, 12500Hz, and 500Hz should not exceed 4dB and 6dB, respectively. Furthermore, the Total Harmonic Distortion (THD) for sound passing through the LED screen should not exceed 1%, ensuring minimal distortion.

Additionally, the effective hole ratio (i.e., the area of holes relative to the total area of the screen) should be at least 9% to maintain a balanced audio-visual performance.

Factors Affecting Audio Quality in Transparent Sound LED Screens

Several factors influence the audio performance of transparent LED screens, including the size, thickness, and arrangement of the perforations, as well as the presence of cavities between layers in the display.
Perforation Size: Studies show that smaller holes generally result in better high-frequency sound transmission, with less sound attenuation at frequencies above 8kHz.

Hole Thickness: The thickness of the perforated material significantly impacts high-frequency audio quality. Thicker holes, particularly in the high-frequency range, cause greater sound attenuation, as well as increased distortion.
Hole Shape: The shape of the perforations also affects sound transmission. The three common hole shapes are:
● Conventional Round Holes: Provide balanced performance but may not excel in specific frequency ranges.
● Forward Horn Shape: Improves mid-frequency sound transmission, particularly in the 500Hz–2500Hz range.
● Reverse Horn Shape: Less effective than forward horn shapes but still provides reasonable audio performance.
Cavities Between Layers: Spaces between the bottom layer and the printed circuit board (PCB) can cause resonance that impacts sound quality, especially in the 5kHz to 8kHz range. The design of these cavities must be optimized to minimize negative effects.
Arrangement of Holes: The arrangement of the perforations (whether regular or irregular) does not significantly impact the sound performance as long as the effective hole ratio is maintained.

Design Considerations for Transparent Sound LED Screens

The design of transparent sound LED screens involves several crucial steps to ensure both excellent visual and audio performance.
● PCB Design: The positioning of chips and driving circuits on the PCB must be optimized to maximize the perforation area. This ensures an even distribution of holes and a sufficient effective hole ratio.
● Hole Size and Distribution: The perforation size should range from 0.6mm to 4mm in diameter, depending on the required balance between sound transparency and manufacturing complexity.
● Reducing Interference: Light interference from the environment, especially from behind the screen, can significantly degrade the screen’s visual quality. To minimize this, the perforated holes should be coated with light-absorbing materials to prevent stray light from affecting the display.
● Meeting DCI Standards: According to Digital Cinema Initiatives (DCI) standards, transparent sound LED screens must meet stringent safety and performance requirements. Embedding the main speakers into the screen body can improve the physical security of the screen and ensure compliance with DCI’s physical safety guidelines.

The World’s First Transparent Sound LED Screen

The world’s first transparent sound LED screen was unveiled on June 26th by Unilumin Technology at the Deji Plaza in Nanjing, China. The screen, designed for cinema applications, measures 20.48 meters in width and 10.8 meters in height, offering ultra-high-definition 4K resolution and a high refresh rate of 96 frames per second. The peak brightness reaches up to 300 nits, providing exceptional contrast, color accuracy, and detail rendering.

This groundbreaking transparent LED screen utilizes a unique perforation design and places the main speakers behind the screen to optimize both sound and visual performance. This design not only improves the sound transparency but also significantly reduces the space required behind the screen, allowing for a more spacious and comfortable theater environment for viewers.

Conclusion

Transparent sound LED screens are a revolutionary technology in the digital cinema industry, offering a seamless integration of high-quality visuals and sound. By using advanced perforated structures or integrating acoustic technologies, these screens enhance the viewing experience by aligning audio with visual content. As the technology continues to evolve, transparent sound LED screens are poised to lead the way in the future of cinema, improving both the aesthetics and functionality of movie theaters worldwide.