Audio Roundup: The Sweet Sound of Miniaturized, Efficient Audio Devices

With the goal of improving the efficiency, utility, and performance of audio systems, several companies have recently released new devices to overcome key challenges in the audio electronics industry. While these new products take many forms—from class D amplifiers to solid-state speakers—they provide designers with tools to make audio devices smaller and easier to use.

Novosense Unveils Automotive Class D Amplifier

Up first, Novosense recently unveiled a new class D audio amplifier that targets automotive applications. The class D amplifier architecture, with its superior efficiency compared to other designs, is a natural choice for automotive engineers, especially working with battery-powered vehicles. 

In terms of integration, the NSDA6934-Q1 supports up to four output channels, each of which can be driven up to 75 W for a total of 300 W output power. In addition, the amplifier includes a low-latency mode, which can reportedly reduce the transmission path delay by up to 70%, improving the audio experience for end users and simplifying the design process for engineers.

In modern automobiles, many different speakers are placed throughout the vehicle, making a multichannel, high-power audio amplifier useful. Image used courtesy of Novosense

In addition to its high-power outputs, the chip includes several protection features and improved EMC performance, making it easier to integrate in compact environments. The amplifier’s operation is also tunable, ensuring that the design experience comes with fewer headaches and more flexibility. Novosense has scheduled the NSDA6934-Q1 for mass production in the first half of 2025, with samples available now.

Nuvoton Reveals Filter-Free Class D Amp for Consumer Devices

Nuvoton has also released a new class D amplifier targeting consumer electronics. Consumer electronics, such as Bluetooth speakers or wireless doorbells, must use their limited stored energy in the most efficient way possible. Nuvoton designed its new amplifier chip to improve the user experience and reduce the frequency of charging while simultaneously improving performance.

The Nuvoton class D amplifier integrates many of the necessary components on-chip, allowing denser integration in small audio devices such as speakers or handheld tablets. Image used courtesy of Nuvoton

The NAU82110YG (datasheet linked) offers improved SNR performance, with a reported 103 dB SNR, ensuring that, even at high gains, noise does not become an issue. Furthermore, the low quiescent current of 6 mA at 12 V input helps to preserve power. The chip can provide up to 18 W of power to a 4-Ω load and features a 4.6-ms startup time in addition to numerous safety features.

xMEMS Solid-State Speakers Debut in AI Glasses

Finishing off this roundup, xMEMS has recently announced that its Cowell micro speaker will be shipping in a new AI sports glasses product from BleeqUp. The micro speaker, measuring just 3.2 mm × 6 mm, uses solid-state technology to considerably reduce the size of audio transducers while delivering high-fidelity sound to the user.

Compared to traditional coil-and-magnet technology, xMEMS' solid-state speaker technology leverages the piezoelectric effect to produce sound waves, removing the need for bulky coils and magnets and allowing speakers with similar sound levels to be integrated in smaller devices.

With the Cowell micro speaker, shown here in a hearing assistance reference design, audio transducers can be incorporated in extremely small designs. Image used courtesy of xMEMS

In the BleeqUp glasses design, the Cowell micro speaker acts as a tweeter, handling primarily high frequencies and leaving lower audio frequencies to a traditional dynamic woofer. While the Cowell design itself is not new, the integration of xMEMS’ technology in a commercial product demonstrates the potential value of solid-state speakers and sets the stage for the company's next-generation Sycamore speaker, which will reportedly deliver the full audio spectrum in a one mm-thick device.

Music to an Audiophile's Ears

When looking at all these new pieces of audio technology, several trends become apparent. For one, higher efficiency is a major focus for all designers, as more battery-powered audio devices are deployed. In addition, the size of audio electronics and transducers is a critical issue that will require higher levels of integration for speakers and supporting silicon. As evidenced by these devices from Novosense, Nuvoton, and xMEMS, audio components are on this forward trajectory toward smaller, better-performing, and more efficient devices.