The Making of Axon Body 3: Adventures in Audio
What’s behind the improved audio quality? Without getting too jargon-y, here's a recap of some of the advancements:
- The sampling rate has increased to 48 kHz. A higher sampling rate means you're essentially capturing more sound per unit of time (the way a video captures more images than a series of photos). This allows you to you capture higher-frequency audio, even things a human ear might not be able to hear. You might be thinking, Why would we want to record things a human can't hear, if the point is to have accurate evidence? Well, for example, some audio frequencies associated with gunshots are at the top of the range; if our microphones can pick those sounds up, it allows for better, more accurate detection that can be leveraged to send notifications or alerts for help.
- There are four omnidirectional digital microphones (up from one). With multiple mics being spaced a few centimeters apart (two on the front, two on the bottom), they capture sound at slightly different times, depending on which direction a noise is coming from. The processing power inside the camera can help determine the source of the sound based on when it “hits” each microphone, and then optimize for that. So, more microphones plus more processing power equals a better ability to parse out the specifics of a sound, whether it's what direction it came from, or if it's wind or ambient noise that can be de-emphasized so that human voices are primary.
- LE-centric algorithms can advance over time. We’re using a Qualcomm chip set, which packs a punch in terms of digital signal processing (DSP) power inside the device. That means as we develop new algorithms to detect and optimize for different sounds, the device hardware can keep up. For starters, we’re incorporating Nokia’s OZO Audio technology, a leading edge spatial audio capture and processing solution featured in some of the world’s most advanced smartphones. (Fun fact: We were introduced to the Finland-based OZO team by our VP of Imaging, Juha Alakarhu, who worked on some imaging magic for Axon Body 3 from our offices in Tampere.) There may be other audio technologies incorporated in the future that can be accommodated by the hardware.
To hear Ryan tell it, working on these complex audio issues was “a lot of fun.” He helped with every decision, from where the mics should go, to what their vents should be made of, to how to incorporate the DSP technology. But the highlight was when he built a sound chamber with two colleagues to use for audio experiments after a whirlwind online auction win. He spent a lot of time in that chamber, experimenting with nail guns and blank-firing guns that would put our audio algorithms to the test.
Ryan and the custom-built sound chamber where Axon Body 3’s audio was tested and refined.
We’re proud of all the work by people like Ryan that has gone into Axon Body 3. We look forward to your feedback once you’ve tested it for yourself.