High-resolution wireless audio is the future for the market, and consumers are demanding it.
High-resolution wireless audio is the future for the market, and consumers are demanding it. In fact, in recent surveys conducted by Qualcomm, sound quality is the top priority for end-users, with 52% of the respondents saying that they are seeking high-resolution or lossless quality audio. To support this demand, streaming services from Apple, Spotify, and Amazon have all made recent commitments to supporting high-resolution streaming audio in the future, but how will wireless earphones and other consumer hardware keep up? The consumer experience will be negatively impacted if device makers don’t catch-up to create products that can support the delivery of high-resolution music to the user. In the case of True Wireless Stereo (TWS) devices, choosing a Bluetooth Audio SoC that supports high-resolution audio codecs with robust connectivity becomes important. Moreover, the speaker drivers deliver the last mile of audio to the user’s ears and choosing drivers that can deliver high-fidelity audio in a compact form factor becomes very critical.
The article will focus on the evolution of TWS and some of the technologies and trends that are driving its growth. It will provide an overview of TWS and considerations that product design and engineering teams must know about in order to create the devices of the future that will continue to drive market growth.
TWS earbud market growth
The first TWS earbuds, Bragi Dash, were released in 2015, but it was not until Apple’s announcement of AirPods in 2016 that the technology started to see increased interest. In subsequent years, the market for TWS devices has continued to grow. In fact, in 2020 alone, the number of TWS devices grew by over 30% compared to the year before. Costs have also changed — Bragi Dash came with a price tag of around $300 when they first launched. Almost a year later, the company released a new model going by the name of ‘The Headphone’ roughly at half the price of its predecessor. Today, brands like JBL, Skullcandy, OnePlus, etc. have come up with entry-level earbuds under $100 that offer solid performance for the price. As the technology gets more affordable, it is expected to penetrate the new and growing markets even further.
On the high-end of the market, TWS manufacturers will continue to push the boundaries and add new features to differentiate from the rest, grow revenue, and maximize value capture. The potential of TWS has not been fully realized and continued innovation in several key technology areas ensures that the growth and evolution of these devices will occur, as seen in Figure 2, which roughly illustrates the evolution of TWS audio features.
The role that high-resolution audio streaming plays in TWS growth
Due to the popularity of lossy codecs such as MP3, AAC, etc., used for streaming audio, most consumers grew accustomed to listening to lossy, compressed versions of their favorite music tracks. These popular codecs have served a critical purpose in making music more widely available. They also made the acquisition and distribution of music cheaper and more accessible for more listeners, for listening to music on the go through a wide variety of devices. However, audio enthusiasts have long been waiting for superior, lossless audio quality from the big streaming services providers. With the recent push on high resolution or lossless audio from streaming vendors and related announcements from major Bluetooth SoC vendors like Qualcomm, more consumers will discover the pleasure of listening to high resolution music, and will start demanding it on their TWS devices.
Speaker drivers in earphones deliver the last mile audio in the audio chain in ear-worn devices such as TWS and are therefore critical to the delivery of high-resolution music to users’ ears.
Balanced Armature (BA) speaker drivers deliver improved fidelity and detail over traditional dynamic drivers in TWS devices. BAs produce a high-fidelity sound through the use of a reed that is balanced in the static magnetic field between two magnets within the driver’s outer shell. A stationary coil driven with the audio source magnetizes the reed, causing it and the attached diaphragm to move in step with the music. The sound produced is pure in quality and clarity and is free of unwanted resonances in the audio band. BAs also have a superior high-frequency response making them a good choice for high-resolution music. In addition to delivering high-fidelity sound, BAs also comes in a compact form factor and consume lower power compared to the incumbent dynamic drivers.
Sometimes BAs are combined with dynamic drivers in what is commonly called a hybrid speaker driver. In this configuration, the BA driver functions as a tweeter to deliver on the critical high-end portion of the audio spectrum, while the dynamic driver functions as a woofer. The hybrid combination helps TWS designers deliver products with superior sound quality combined with active noise cancellation (ANC). Hybrid drivers provide a superior value proposition to TWS designers and are starting to become more common in high-to-mid end TWS devices. BA technology advancements will continue to improve power consumption while delivering high-fidelity sound in compact form-factor designs, allowing for more freedom of choice and product innovation for OEMs.
Other important technology trends and factors that support the TWS experience include:
Active Noise Cancellation (ANC) and transparency mode have become common features in recent years, but some TWS devices are now using artificial intelligence (AI)-driven adaptations to automatically change the noise cancellation or transparency mode settings by analyzing the sound in real-time. The adaptation algorithms account for changes in the ambient environment and even variations in the fit to deliver the best possible performance in all conditions.
AI-enabled approaches are also starting to be used for contextual awareness, hearing enhancement and output audio processing in TWS devices. For example, contextual awareness could create functions such as contextual volume control and noise suppression for TWS devices based on your environment. This could be used to have the volume lower when a device recognizes someone is saying your name, or noise suppression settings are automatically adjusted when the user is walking through a very loud or very quiet environment.
Running complex real-time AI algorithms on TWS devices require power-efficient processors with sufficient horsepower and memory. With improvements to edge audio processors and algorithms, TWS devices will continue to get smarter.
Techniques such as spatial audio can deliver an excellent theatre-like experience for users consuming rich media content. Spatial audio refers to a suite of algorithms, including directional audio filtering and head-tracking that provide the feeling of being present in a three-dimensional acoustic scene to a listener. Spatial audio and other output audio processing techniques will deliver users an immersive experience when enjoying videos, movies, or video games.
While voice assistants are widely used in devices such as smart speakers, they are still in the early stages of adoption in TWS and other hearable devices. As users get more comfortable with using their favorite voice assistants on the go and with the increasing maturity of the voice assistant ecosystem, the adoption of voice assistants in TWS will likely take off. Also, with continued improvements in voice processing technology, features such as natural language processing (NLP) for command recognition and voice biometrics for user identification might start making their way into TWS devices in a not-too-distant future.
The TWS market continues to grow and evolve as each generation brings several new features to the market, but this rapid pace of evolution puts pressure on all TWS manufacturers to invest significantly into R&D to keep pace with the market. Designing for TWS is a complex engineering challenge, requiring in-depth knowledge across multiple domains and solid system-level acoustic expertise. While the top OEMs have in-house engineering teams comprising hardware, software, algorithm engineers, and acoustic expertise, mid-tier and smaller device makers face an uphill task to keep pace with innovation. Ground-up development is expensive and often prone to delays.
The improvements in the sound quality coupled with advanced AI features will bring quintessential experiences to consumers through their TWS devices. We are set to witness some phenomenal breakthroughs in the years to come.
This article was originally published on EE Times Europe.
Raj Senguttuvan is the director of strategic marketing at Knowles Corporation.