Boosting Audio System Sustainability with Dirac 

Audio equipment manufacturers are realizing that it’s time to get serious about sustainability. We see that companies are now striving to both enhance audio quality and reduce the environmental impacts of their hardware. At Dirac, we are thrilled to be able to contribute to this change with cutting-edge signal processing technologies that create smarter, more efficient system designs. This article explores how our innovations are transforming the audio industry and setting new benchmarks for sound quality, all while helping reduce environmental impact. 

A significant pillar in our portfolio is Unison (MIMO mixed-phase impulse response correction) technology. This approach enables speakers to work collaboratively, producing superior audio output that typically would require additional speakers. By enhancing the efficiency of speaker cooperation, we can reduce the total number of speakers and amplifier channels necessary in a vehicle. In one indicative case, our team in China developed a high-end car audio system that reduced the number of speakers needed from 23 to just 13. 

This reduction is not merely about minimizing hardware; it directly translates to less material usage and a reduced environmental footprint. Such streamlined design also results in decreased weight, improving the vehicle’s overall fuel efficiency. 

Moreover, the reduction in the number of speakers and amplifier channels also leads to significant energy savings. With fewer components to power, the overall energy consumption of the audio system is reduced, contributing to a more energy-efficient vehicle. This is particularly important in the context of electric vehicles (EVs), where every watt of power saved can extend the vehicle’s range. 

Unison technology also improves the overall audio experience by ensuring precise synchronization and calibration among the remaining speakers. This technology leverages advanced algorithms to correct phase and timing issues, delivering a more cohesive and immersive soundstage. By reducing the number of speakers without compromising on audio quality, Unison technology showcases how innovation can drive both performance and sustainability. 

Another innovation that supports sustainability goals is Dirac Virtual Center. Traditionally, optimal audio staging in a vehicle required a center speaker. However, our Virtual Center technology brilliantly simulates the effect of a center speaker using the existing speakers in the vehicle. This not only simplifies the audio system but also reduces the number of components needed, further contributing to material and cost savings. 

Virtual Center technology works by processing audio signals in a way that creates the illusion of a center speaker, ensuring that dialogue and other central audio elements appear to emanate from the center of the soundstage. This is achieved through sophisticated signal processing algorithms that manipulate the timing and phase of audio signals, creating a focused and balanced audio image. 

By minimizing the need for a physical center speaker, we also reduce the complexity of the audio system’s installation and setup. This makes it easier for manufacturers to integrate high-quality audio solutions into their vehicles without the need for extensive modifications or additional wiring. The result is a cleaner, more streamlined interior design and a more straightforward manufacturing process. 

Our nonlinear control (NLC) technology, which we will present at AES 2024, uses machine learning to enhance loudspeaker performance while reducing the need for heavy and expensive components. By employing Long Short-Term Memory (LSTM) neural networks, we can make the driving force on the voice coil (the part of the speaker that turns electricity into sound) more consistent, improving the mechanical design and compensating for magnetic limitations. 

NLC adjusts the voice coil current to correct force factor irregularities (inconsistencies in the voice coil’s efficiency) without requiring complex mechanical measurements. In tests with an otherwise suboptimal driver, our technology reduced distortion by 10 dB, nearly matching the performance of a well-designed driver. 

Our NLC technology simplifies audio systems by eliminating the need for feedback loops, sensors, and feedback mechanisms, which cuts costs and enhances sustainability. This makes high-quality audio systems more affordable and environmentally friendly. 

A key factor of our NLC technology is its real-world effectiveness, where factors like temperature and aging can impact speaker performance. The LSTM neural networks get ahead of these changes at manufacture time, ensuring consistent audio quality in a range of external conditions. This robustness makes NLC ideal for automotive and portable audio applications, where environmental conditions vary widely. 

Additionally, by focusing on voice coil current and force factor nonlinearity, our NLC technology targets the most stable and predictable aspects of speaker operation. This approach eliminates the need for complex mechanical signal acquisition, such as displacement or velocity measurements, which are costly and difficult to implement in production. 

In addition to developing technologies aimed at new hardware, we also focus on maximizing the lifespan of existing equipment. Dirac Live, our home room correction software, plays a pivotal role in this regard. By fine-tuning audio output to suit the specific acoustics of the environment, Dirac Live ensures that speakers perform optimally, regardless of their age or provenance. Dirac Live also gives users the ability to tweak the sound character of their speakers, which means that users can change the character of their existing setup to meet their evolving tastes. This prolongs hardware lifespan, reducing the need for frequent replacements and minimizing electronic waste. 

Dirac Live uses advanced algorithms to analyze the acoustic properties of a room and adjust the audio output accordingly. This process involves measuring the room’s frequency and impulses responses and applying corrective filters to address any acoustic anomalies, such as reverberation or standing waves. By doing so, Dirac Live enhances the clarity and accuracy of the audio, making even old speakers sound better than ever. 

At Dirac, our mission extends beyond delivering superior audio quality. We are committed to pioneering technologies that save time, money, and resources. By reducing the number of speakers and using advanced signal processing techniques, we are enhancing the audio experience while contributing to a greener future. Our efforts in sustainability prove that high performance and environmental responsibility can go hand in hand.