Webinar: Elevate Your Reality: Audio Design Solutions for Smart Glasses

Analog Devices

Webinar Date: February 13, 2024

Elevate Your Reality: Audio Design Solutions for Smart Glasses

This post covers Key Takeaways and Frequently Asked Questions from the Analog Devices Elevate Your Reality: Audio Design Solutions for Smart Glasses webinar regarding use-cases and benefits of Open-Ear Audio for smart, augmented, and virtual reality glasses. Whether you’re a seasoned professional or a curious newcomer, you’ll find plenty of valuable information watching the webinar. Links to the Webinar, Resources, and Related Content are provided within the post. A copy of the PowerPoint presentation will be provided for customers that register to watch the recorded webinar. All Snippets and Content Compliments of Analog Devices.

The expected growth of smart and augmented reality glasses is leading designers to adopt a new solution for sound playback: Open-Ear Audio. Open-Ear audio is an important aspect of the latest technology in virtual reality or “Smart Glasses.”. Headphones that do not isolate ambient sound from entering the ear canal are known as open-ear audio devices that allow the user to be aware of what is happening around them.

Applying this methodology creates challenges for designers hoping to maximize sound quality. Analog Devices’ Audio Marketing Manager, Ryan Doyle leads this webinar with use cases and benefits of this new and emerging form factor, along with help on how to improve audio performance in innovative designs. Among the challenges of implementation, time-to-market minimization with limited audio expertise is also discussed.

In this webinar, you will learn about the use-cases and benefits of this new form factor, some of the challenges, and the Analog Devices technologies to help improve audio performance for your designs.

Tune in to learn:

  • What is Open-Ear audio playback?
  • What are some useful applications and form factors?
  • How can you create high-performing audio solutions?
  • How can you minimize time to market even without much audio expertise?

Frequently Asked Questions

are there mainline linux drivers for these digital amplifiers?

  • Great question! We are going to connect with some coworkers to get the right answer for you. We will update this post once we hear something back.

can MAX98390 be used to drive a piezo speaker?

  • We are going to check with someone on this. We will update this post once we hear something back.

which device is optimised/recommended for bone conduction applications?

  • we are going to check on this. We will update this post once we hear something back.

You mentioned a laser characterization service as part of the support for the MAX98390. Can you elaborate? Why is that needed?

  • When you receive a MAX98390 EV SYS and start designing your prototype, DSM Sound Studio walks you how to get an approximation of the excursion and temperature bounds of the speaker and enclosure. That’s why we include a temperature sensor on the EV SYS to collect ambient temperature information, for example. But once you are finished with your design and have your speaker chosen and placed where it will be for production, it’s time to get a more accurate reading. So, you can email us a request for calibration, and our applications team will receive in a few samples of your prototype and measure it very precisely using our proprietary measurement system. You’d want to make sure that the transducer surface is exposed so that we are able to measure it. You can find more details about this process on our website.

Earbuds and headphones usually feature active noise cancelation at this point. Is ANC feasible in an open-ear form factor, such as smart glasses?

  • That’s a great question. While it might not be impossible, there are a lot of big challenges to overcome to have effective noise cancelation. By the way, let me clarify by saying I’m not referring to canceling out background noise for phone-calls. There are a host of software algorithms for that, with our own Pure Voice algorithm included as well. But for canceling background noise so that you can hear music better while on the train for example, that isn’t that feasible from an acoustics standpoint. The distance of a feedback measurement microphone would be far away from where sound enters your ear canal, so there are limits on the frequency range of effective cancelation. And in order to cancel noise, the speaker has to work fairly hard, which is even harder given how far away the speakers are from your ears. If such a feature is introduced, I imagine that the effectiveness will be very limited. Another thing to keep in mind is that open-ear listening goes hand-in-hand with situational awareness and ANC can get in the way of that.

You mentioned Bone Conduction and that the technology is not currently being used on AR, VR and smart glasses. Why not, and do you expect that to change in the future?

  • One of the tricky things about bone conduction is that you need to have solid contact near the opening of your ear to transmit vibrations to your eardrum. I think one of the reasons that we don’t see it used in glasses or headmounted displays is that since these devices have to fit such a wide variety of user head shapes, it can be a major challenge to make it work for everyone. If good contact isn’t made, you might get very little sound at all. There’s a chance that we will see it more in the future though if that shortcoming can be addressed, with hearing enhancement being a logical application. In that case, bone conduction could be an advantage; with traditional speakers and open-ear playback, there’s a slight delay in audio getting from the speaker to your ear as it travels through the air, and bone conduction doesn’t have that problem. Very low latency is critical here.

What audio trends are you watching in the coming years for open-ear audio?

  • I think we’re going to continue to see improvements in quality with respect to size. I think for a lot of end-consumers and manufacturers, the goal is to have glasses designs that don’t have to compromise fashion for electronics. So there will always be a desire to minimize electronics and maximize battery life. This is one of the reasons that Analog Devices is a trusted partner with our customers, since our products excel at efficiency and small size.
  • I’m also expecting voice assistants to play a larger role in smart glasses, with spoken audio responses being a key part of the experience. This isn’t a new idea, but I think we are getting closer to having all-day devices that can instantly answer your questions and perform other tasks without having to take out a phone.
  • Farther down the road, I’d like to see higher speaker-count devices; maybe that implement new speaker tech like MEMs. With higher amounts of speakers on each arm, there could be a lot of improvements in loudness, lower leakage, and more immersive spatial audio. Spatial audio or surround sound could help consumer discern between different notifications based on where the sound is coming from for example, leading to more accurate outcomes. Our amplifiers typically support multi-channel TDM inputs with the MAX98388 capable of playing TDM16 streams.
  • One last area that I could see some real innovation is in outloud hearing assistance. Imagine wearing glasses that could amplify voices that you are looking at. This could help people with mild hearing loss who don’t want to wear hearing aids. There’s a lot of stigma with this and many people aren’t getting the help that they need because of it. There are already concepts of these products that have been announced, with production coming soon. One area that Analog Devices can help is in the form of ultra low power DSP. Mics embedded in the glasses will be asked to beamform to pick up sound in front, and low latency processing and output will be needed to make the experience natural when the sound reaches a person’s ears. Our ADAU1860 with a Fast DSP core is an excellent fit for that.

EVAL-ADAU1860EBZ (Eval Board for ADAU1860)

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Example Webinar Slides

-Much more in-depth slides and a copy of the PowerPoint presentation will be provided for customers that register to watch the recorded webinar.