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Reimagining Personal Audio Experience

Do you enjoy listening to music on headphones? Do you feel there’s a compromise in the musical experience compared to a Hi-Fi speaker system? Do you have different headphones for different types of music or activities? If you answered yes to any of these questions, then you might find this piece interesting.

As someone who enjoys listening to music and watching movies at my own pace without disturbing others, I prefer headphones over my hi-fi speakers. However, I developed a keen ear for high-quality audio gear from my early childhood listening to a home theatre system. When listening to music on a home theatre system, I experience the music in an immersive and lifelike way, making me feel like I’m right there in the moment, whether it’s AR Rahman’s compositions or EDM. However, when using headphones, I noticed that headphones failed to do justice to sound quality across different music genres, and I felt like something was missing. At the time, I couldn’t quite pinpoint the issue.

A few years later, while pursuing my engineering degree, I met my co-founder, Jagath. Like many of our peers, we were searching for a great pair of headphones that could cater to our diverse music preferences, from instrumentals to dubstep, and be suitable for movies and gaming. Unfortunately, we couldn’t find such headphones.

There have been significant advancements in personal audio devices, such as the introduction of Bluetooth for wireless audio, improvements in audio quality and battery life, active noise cancellation technology, built-in voice assistance support, and the launch of smart headsets that can monitor heart rate and blood oxygen saturation. While these advancements were significant, we felt that headphones were still missing the live and immersive experience that speakers can provide. We believed that the audio industry had deviated from its core value of improving audio quality and experience.

Finally, we discovered the missing link when we started researching and developing projects involving hearing implants and audio communication interfaces for safety helmets. These projects aimed to allow users to hear reproduced sounds without using their ears. We were inspired by how Beethoven could listen to his music compositions despite being deaf. It turns out that Beethoven used to put a pencil in his mouth and touch the other end of the soundboard of the piano to feel the vibration of the notes. Many musicians with hearing loss rely on physical interactions to feel the sound, such as touching vibrating surfaces on musical instruments or sensing the vibrations from the floor using their feet. This realisation led us to question the status quo and reimagine the personal audio experience.

We realised that, as humans, we can perceive sound not only through our ears but also through our bodies. Think about the experience of thunder, the sensation of live drums during festivals, the thumping bass in your chest at a music concert, or the rumble you feel while watching movies in a theatre. Our hearing is less sensitive to low-frequency sounds, especially below 120Hz, but we can feel these frequencies through specialised sensory cells called mechanoreceptors, which detect pressure and vibration on our skin, muscles, and joints. Additionally, we can perceive sound through bone conduction, where vibrations are sensed by us when transmitted through our bones, specifically the skull.

Home theatres and Hi-Fi systems utilise multiple audio drivers to reproduce different audio bands like the low, mid, and high frequencies. They also incorporate specialised audio systems called subwoofers, designed to effectively reproduce the sub-bass audio band that are frequencies between 20Hz and 120Hz which we can feel through our body. In contrast, most headphones use a single tiny driver on each side, allowing users only to hear the music and lacking the specialised technology to emulate subwoofers for reproducing sound that can be felt.

Intending to deliver a blissful audio experience and create the perfect conduit between people and sound, Jagath and I embarked on revolutionising the headphone audio experience by developing our Hybrid Driver Technology. Our system combines the principles of air conduction and body conduction using our proprietary Impulse Driver, enabling people not just to hear music but, thanks to bone and skin conduction phenomena, actually feel it.

To illustrate the integration of our technology within headphones, we present an exploded view of the envisioned design.

audio

The working principle behind our Hybrid Driver Acoustics involves the synergy of two distinct audio drivers and the perception of sound. The acoustic system on each side of the headphone incorporates a dynamic driver, similar to a conventional headphone. It reproduces mid and high frequencies by converting audio signals into sound waves and directing them to the listener’s ears through air conduction. Simultaneously, our proprietary impulse driver converts the audio signal into corresponding mechanical impulses precisely directed to the specially engineered Active Earpads. These Active earpads act as a virtual diaphragm, directing the impulse force to the listener’s head, specifically to the skin and skull region surrounding the head. As a result, the Hybrid Driver technology effectively emulates elements of a full-range driver and a subwoofer system, opening up a new dimension in headphone audio across various music genres and use cases, such as movies and gaming. It allows listeners to experience sound to the fullest, providing a high-fidelity, fully immersive, and personalised audio experience through headphones.

The ultimate question that remains is: How good are headphones with this tech, and is it all just on paper?

Follow us to find out the answer.

Article by –┬áNAVAJITH KARKERA, CEO,┬áRAPTURE INNOVATIONS LABS PVT. LTD.