Rewriting the rules of sound experience beyond traditional headphones, an Indian deep tech startup is transmitting audio through skin and bone! What are the technology and design secrets? Navajith Karkera from Rapture Innovation Labs tells their story to EFY’s Akanksha Sondhi Gaur and Saba Aafreen.
Q. Can you explain what Rapture Innovation Labs does?
A. Rapture Innovation Labs is an audio technology startup that revolutionises personal audio experiences through patented innovative technology. With this, people do not just hear music; they feel it, bringing a live concert experience. Using our patented ‘Impulse Driver’ technology, we aim to recreate this immersive sensation of live sound; something conventional headphones do not deliver.
Q. What inspired the startup, and what gap in the market were you trying to address?
A. The spark came from my father’s home theatre. Standing there, you did not just hear the music; you felt the subwoofer’s low-frequency vibrations pulse through your body. That is what live concerts feel like. But headphones? They could never recreate that experience due to limitations in size, power, and design. While pursuing engineering, my co-founder and I were deeply involved in helmet communication systems and hearing implant research, exploring skin and bone conduction technologies. During one experiment, we integrated our transducer into a pair of headphones just to see what would happen. The result surprised us: we had recreated the physical sensation of sound. That chest-thumping, body-vibrating feeling from a subwoofer is now possible in headphones. We 3D-printed two crude prototypes for ourselves. They were rough, unpolished, but they worked. Soon, others wanted them too. Demand built organically despite the prototype-level design quality. To validate our observations, we used a head-and-torso simulator to benchmark the frequency response and harmonic distortion of our headphones against conventional headphones. The data confirmed it: our technology delivered a significantly enhanced listening experience. That is when we knew we had something. We filed patents, formalised our research, and began developing the transducers and headphones. We incorporated Rapture Innovation Labs in 2018, and by 2019, we had fully pivoted from research projects to audio tech with one clear mission: deliver a physical sound experience where people feel music, not just hear it.
Q. Could you walk us through your product journey and where the company fits into it?
A. Our journey began with research into reproducing sound via skin and bone conduction, leading to our proprietary technology. We enable sound through skin and bone conduction with our Impulse Drivers.
From 2019 to 2022, we developed the transducer and built a headphone around it, launching the first Sonic Lamb headphones in 2023 via crowdfunding for the US and European markets. Later that year, we expanded into India through our website, Amazon, and retail channels.
We are now launching Sonic Lamb Gen 2 in June, recently recognised with a CES Innovation Award in the headphones and personal audio category. This generation refines sound, comfort, battery life, microphone performance, and overall reliability based on two years of engineering learnings. Beyond headphones, we are exploring automotive applications, integrating transducers into seats to let users physically feel music through the body.
Q. Can you give an overview of your company, including its legal structure, founding team, team size, design setup, and product plans?
A. We are a private limited company with a current team of about 52 people across various functions. Our name, Rapture, reflects the feeling of intense joy and pleasure, which we aim to deliver through audio experiences.
We are based in Hubli, roughly 400km from Bengaluru, operating out of a 5000-square-foot (approximately 464.51 square metres) facility split between manufacturing and design, engineering, marketing, and other functions. About 25 team members focus on production, while the rest work in research and development (R&D), design, engineering, marketing, testing, app development, and operational roles like HR and accounts. Our team is primarily focused on engineering and manufacturing.
In terms of products, the first-generation Sonic Lamb headphones are already on the market; the second generation is set to launch in June 2026. We are also collaborating with automotive companies to integrate our technology into vehicle seating, which is expected to take around two more years to commercialise.
Q. How long did it take to develop the company, and what were the key R&D breakthroughs?
A. Early trials in 2019 showed conventional drivers cover mids and highs, but frequencies below 200Hz were the real gap, as subwoofers are impractical in headphones.
This led to about a year of refining Impulse Drivers for low-frequency reproduction, redesigning the headphone architecture to transmit mechanical impulses without distortion or latency, and developing proprietary test infrastructure to ensure consistency and certification like Conformité Européenne (CE), Federal Communications Commission (FCC), and Bureau of Indian Standards (BIS). To overcome India’s limited audio hardware expertise, the team joined Denmark’s SoundHub accelerator, with support from Bang & Olufsen and Harman. Manufacturing precision was a challenge, prompting in-house production. Early sales were modest at ₹10 to 20 million, with expectations now at ₹80 million in 2026 and ₹150 million next year.
Q. Can you share your sales numbers or revenue so far?
A. So far, we have shipped over 7000 units and generated roughly ₹80 to ₹90 million in revenue. Early on, manufacturing capacity constrained growth, and customers had to wait several months. After moving manufacturing in-house, production stabilised, and most sales have happened in the financial year 2025-26. We are now positioned to scale production and sales in the coming years.
Q. Have you raised external funding, or is the company bootstrapped?
A. We have raised funding through a mix of grants and equity investments. Early R&D was supported by government grants from institutions such as the Government of Karnataka, the Department of Science and Technology (DST), and the Indian Institute of Technology (IIT) Bombay. Winning innovation challenges also provided cash support. As technology matured, we raised multiple angel and venture capital rounds.
Q. Are you looking to expand partnerships, vendors, or academic collaborations?
A. With production challenges resolved, we are expanding sales channels beyond our website, including Amazon and retail partners like Imagine, iPlanet, and Future World, reaching roughly 100 stores. Internationally, we are in discussions with distributors in the US and Europe. On the supply side, we maintain a stable vendor network but remain open to high-quality suppliers. Academically, we collaborate with research institutions to study hearing safety and the wellness potential of our technology, which reproduces low-frequency sound through skin and bone, reducing ear exposure while enhancing the listening experience.
Q. Could you explain the fundamental architecture of headphones?
A. Most headphones use a standard setup of a Bluetooth chipset, amplifier, and conventional dynamic drivers, largely unchanged across price points from ₹1000 to ₹100,000. Sonic Lamb differentiates itself by adding our Impulse Driver, a transducer that converts audio into mechanical vibrations. Coupled with the ear pads, it moves with each beat, creating pressure changes felt through skin and bone, as I have said earlier. Frequencies below 200Hz, like bass and sub-bass, are handled by it, while higher frequencies are reproduced by conventional drivers. This lets users physically feel low-frequency resonance, similar to standing near drums or at live concerts, without risking dangerous volume.
Q. So does it essentially work on a bone conduction mechanism?
A. It is a blend of skin and bone conduction, though primarily felt through the skin where the ear pads touch the head. The Impulse Driver generates pressure differences that the skin senses directly, while vibrations also travel through the bone. Bone conduction adds depth, but the core experience comes from precise skin transmission.
Q. Since you built the Impulse Driver in-house, how does this hybrid design work?
A. In our architecture, frequencies below 200Hz are reproduced by the Impulse Driver, which converts audio signals into mechanical movement transmitted through the ear pads and felt through the skin and bone. Frequencies above that range are reproduced by conventional dynamic drivers as audible sound waves. Since the dynamic drivers do not need to reproduce low frequencies, they can be tuned more precisely for mids and highs with lower distortion and higher accuracy. At the same time, our product physically reproduces the bass, creating stronger immersion without compromising audio clarity. So, the system uses two transducers and two media.
Q. How do headphones deliver safe, accurate tactile vibrations while maintaining comfort and audio fidelity?
A. The headphones use woofer pads to transmit the mechanical impulses of the Impulse Driver to the user’s body, with materials, foam density, and structure optimised for clear, distortion-free tactile sensation. The outer leather layer ensures comfort and durability, while the Gen 2 over-ear pads enhance fit for all users. Separate digital signal processing (DSPs) and amplifiers precisely manage audible and tactile signals. Tactile accuracy is ensured through strict manufacturing standard operating procedures (SOPs), laser displacement verification on dedicated jigs, and manual listening by trained testers. After assembly, headphones are tested using silicone artificial ears with microphones and benchmark tracks to confirm correct frequency response and consistent audio quality. Continuous R&D further refines materials, mechanical design, and signal processing to optimise comfort, tactile fidelity, and overall sound experience.
Q. What testing methods were used to validate audio fidelity, vibration response, and overall system performance?
A. We use a combination of advanced acoustic testing, custom engineering validation, and human listening tests. For audio fidelity, we use a head-and-torso simulator (HATS), an artificial head with calibrated microphones that replicates human hearing. Some tests were conducted in Denmark due to the high cost and limited availability of such equipment in India. We also perform environmental and durability tests in temperature, humidity, and ultraviolet chambers, as well as in lifecycle chambers, while developing our own jigs and fixtures to test components like buttons and the intensity dial for up to 500,000 cycles. Since the Impulse Driver is a new technology without established standards, we created custom testing equipment and used laser-based measurements in production to verify low-frequency accuracy and consistency. In addition, extensive human listening tests using trained team members and reference music tracks help evaluate sound quality, balance, and real-world performance across prototypes and production batches.
Q. What were the key design challenges in synchronising tactile feedback with acoustic output, and how were they addressed?
A. The main challenge was reproducing low-frequency vibrations naturally while keeping precise left-right balance across thousands of units. Our ear pads act as diaphragms, and careful tuning of materials, from plastic and metal to foam, ensures vibrations pass efficiently without phase mismatch. Synchronising air-transmitted sound with body-conducted vibrations required improving the transducer’s sensitivity and refining the entire transmission chain (2019–2023). To reduce distortion, low frequencies are handled by the Impulse Driver while mids and highs use a dynamic driver, achieving ~0.001% distortion versus 0.1–0.5% in premium headphones. Early Indian production faced quality and timeline issues, so R&D and assembly were moved in-house, while injection-moulded parts and PCBs remain outsourced. Collaborations with advisors and Denmark’s SoundHub programme provided advanced testing and engineering support. Signal processing uses a Qualcomm SoC with a DSP, combined with firmware and psychoacoustically tuned audio for meditation, workouts, and focused listening. Overall, the technology was developed from first principles, leveraging mechanical and electronics expertise to deliver an immersive, precise, distortion-free tactile audio experience.
Q. What manufacturing design challenges did you face while building this globally benchmarked architecture?
A. The main challenge was that our headphone architecture is far more complex than conventional designs. Typically, headphones use a single dynamic driver per ear, housed in a simple enclosure that contains the electronics. In our case, the Impulse Driver must work in close coordination with the dynamic driver, which significantly increases internal complexity and part count, requiring much greater precision during assembly. This initially created difficulties when we tried outsourcing production to a contract manufacturer, which is why we eventually moved manufacturing in-house. Today, we have trained a team of about 30 people to produce the Impulse Drivers and assemble the Sonic Lamb headphones, allowing us to maintain close monitoring and attention to detail. While core manufacturing will remain in-house, we are exploring outsourcing simpler assemblies such as the headband, while keeping the final assembly and related processes internally, where specialised know-how is required.
Q. How are you protecting the core technology?
A. We protect the technology through multiple layers. First, we have three granted patents, with a few more currently in the patent-pending stage, and we plan to file additional patents in the coming quarter. Second, a significant part of the system is our firmware and DSP tuning, which are embedded in the SoC and developed in-house. Third, because we manufacture the Impulse Drivers and assemble the headphones in-house, a large portion of the advantage lies in manufacturing and process know-how, which makes it difficult to replicate even through reverse engineering. Finally, we maintain defensibility through continuous R&D, with plans to launch improved products each year featuring better performance, efficiency, and refined processes.
Q. What makes your technology difficult for competitors to replicate?
A. Traditionally, audio reproduction relies solely on speakers and sound waves, whereas our approach combines sound waves with mechanical movement to recreate the physical sensation of sound, allowing users to experience music not just through their ears but also physically, as in a concert or movie theatre. This was initially an accidental discovery during development, but it introduced a completely new way of experiencing sound. Most users do not realise this gap because they are accustomed to conventional headphones, but when they compare the experiences, the difference becomes clear. Bridging this gap has become our core competency, and our long-term focus is to build products that leverage this capability, ensuring that any future speakers, headphones, or audio devices we develop continue to deliver this physical sound experience.
Q. How did you design ergonomics and hardware to integrate tactile sound efficiently into your headphones?
A. To make the tactile sound approachable, the headphones retain a familiar form factor, lightweight construction, and long-term comfort, avoiding intimidating premium materials. Users can adjust low-frequency intensity via a physical dial, controlling subwoofer-like response without a smartphone app. Durability is enhanced with swivelling earcups, a silicone headband resistant to heat, humidity, oils, and hair products, and easily replaceable earpads to extend product life.
Hardware and firmware optimisations improve efficiency: the first generation used a 1400 mAh battery for about 42 hours of playback, while the second generation achieves the same runtime with a 700mAh battery. The Impulse Driver activates only at low frequencies; the dynamic driver handles mids and highs. Low-power mode engages when bass is minimal, and the driver disables during calls. Together, these strategies are expected to deliver almost 50% better power efficiency without compromising the tactile audio experience.
Q. What were the hardware challenges during development, and how were they solved?
A. The most complex challenge was designing and integrating the Impulse Driver, optimised for low-frequency reproduction and seamlessly embedded in the headphone architecture. Compared to conventional headphones, the design is far more complex, with additional mechanical parts, dual amplifiers, a powerful DSP, and a physical dial for adjusting impulse intensity. Externally, typical; internally, intricate engineering.
Development spanned nearly four years, with two more years to stabilise manufacturing. Many components underwent dozens of iterations, sometimes up to 30 cycles, to ensure consistent, high-quality performance. Targeting the premium segment, the product was designed to exceed expectations set by global audio brands. Achieving this required persistent experimentation, rigorous validation, and a committed engineering team, building a world-class tactile audio product from India despite the country’s limited domestic ecosystem for audio hardware development.
Q. What challenges did you face building a deep tech hardware startup in prototyping, supply chain, and funding?
A. Building a deep tech hardware startup involved intensive prototyping with repeated iterations and in-house test equipment to ensure performance and reliability. Supply chain challenges included sourcing premium materials such as metal, leather, magnets, and copper coils, where India’s ecosystem lacked precision, necessitating selective imports from China and close vendor collaboration to achieve flawless finishes and durability. Audio expertise was scarce domestically, so we leveraged mentorship, programs like SoundUp in Denmark, and legacy industry practices. Funding was constrained as hardware attracted fewer investors; early-stage capital came from about ₹8 million in government grants and milestone-based investments. Each iteration required R&D, salaries, prototypes, and custom testing, while demonstrating technological innovation and execution capability, which helped us gain credibility, positioning us to benefit from the 2025 shift toward funding deep tech hardware ventures.
Q. Beyond headphones, which industries or products could leverage your tactile audio technology?
A. Our technology applies to headsets and seating systems. In headsets, gaming and virtual reality (VR) benefit from tactile low-frequency feedback, making effects like explosions or thunder more immersive, while VR headsets gain enhanced sensory depth beyond conventional speakers through Impulse Drivers. In seating, automotive, home theatre, and cinema applications, seats can embed tactile sound to deliver uniform low-frequency experiences, overcoming issues such as uneven subwoofer distribution, rattling, or aftermarket installation requirements.
Q. What does winning the CES Innovation Awards 2026 mean for the company and for Indian hardware innovation globally?
A. For us, this recognition is a major milestone, especially for the R&D team, because it validates the years of engineering effort that went into developing this technology. It is particularly significant because no Indian company has previously won this award in the audio category, making it an important moment not just for us but also for the broader Indian hardware and audio industry. It demonstrates that deep tech innovation in consumer audio can emerge from India and gain global recognition. We believe the award also helps redirect attention back to the core audio experience and sound quality. Over the past decade, much of the focus in the headphone industry has shifted toward features like active noise cancellation or design aesthetics, which are useful but not the fundamental purpose of headphones. Our goal has been to refocus innovation on sound quality, immersive experience, and long-term comfort, and this recognition highlights the importance of advancing the actual listening experience while setting a benchmark for Indian hardware innovation on the global stage.
Q. How will you evolve the platform, including APIs, integrations, or applications beyond personal audio?
A. Our current focus remains on personal audio with headphones and seating solutions, but platform evolution targets VR, gaming, and pro audio via B2B partnerships, supplying our technology to established brands. Simultaneously, we continue scaling the B2C headphone business. The upcoming Gen 2 headphones support specialised audio, leveraging hardware capabilities in collaboration with Dolby and other experts, and future iterations will include active noise cancellation, integrating advanced software and DSP. All launches will be phased in, ensuring that new products incorporate these technical capabilities.
Q. What are your plans for future growth and breakthroughs in immersive audio?
A. We plan to scale production with two new lines for our Impulse Drivers and headphones, expand the team across engineering, sales, and marketing, and strengthen distribution, campaigns, and e-commerce. R&D continues to focus on next-generation drivers, new chipsets, and improved tooling for the Gen 3 product planned for 2028. While early years emphasised engineering and manufacturing, future investments balance technological innovation with market outreach to support global growth. Our goal is to enhance the physical sound experience across multiple form factors, building on early validation from 7000+ users, and positioning Sonic Lamb as the global choice for immersive audio.
