Researchers built a low-cost camera system that recreates sound from vibrations

Researchers at Carnegie Mellon University have developed a camera system that can seemingly detect sound vibrations with a level of precision that makes it possible to recreate the audio without inference or a microphone. A team from CMU’s School of Computer Science’s Robotics Institute (RI) built the system, which has two cameras and a laser. It can detect “high-speed, low-amplitude surface vibrations” that the human eye can’t see, the university said in a press release.

The system features regular cameras rather than high-speed ones used in previous research, which should lower the cost. “We’ve made the optical microphone much more practical and usable,” Srinivasa Narasimhan, an RI professor and head of the Illumination and Imaging Laboratory, said. “We’ve made the quality better while bringing the cost down.”

An algorithm compares speckle patterns captured by a rolling shutter and a global shutter. It uses the differences between the patterns to calculate the vibrations and recreate the audio. A speckle pattern (which is created by the laser in this case) refers to the behavior of coherent light in space after it’s reflected off of a rough surface. That behavior changes as the surface vibrates. The rolling shutter rapidly scans an image from one end to the other, while a global shutter captures an entire image at the same time. 

“This system pushes the boundary of what can be done with computer vision,” assistant professor Matthew O’Toole, a co-author of a paper on the system, said. “This is a new mechanism to capture high speed and tiny vibrations, and presents a new area of research.”

The researchers say they were able to isolate the audio of guitars that were being played simultaneously. They claim that the system was able to observe a bag of chips, and use vibrations from that to reconstruct audio being emitted by a nearby speaker with higher fidelity than previous optical microphone approaches.

There are a lot of potential applications for this tech. The researchers suggest, for instance, that the system could monitor vibrations from machines in a factory to look for signs of problems. Sound engineers could also isolate the sound from an instrument to improve the mix. In essence, it could help eliminate ambient noise from audio recordings.

追求更好音質，Westone、Sennheiser 有線耳機特賣

Amazon 上有發售各大品牌的有線入耳式耳機，當中包括知名的 Westone、Sennheiser 等，他們也會定期推出特價，就像現在偏入門級的 Westone W40 2019、Sennheiser IE300 以及 Etymotic Evo 三款入耳式耳機都正減價發售。…

Dolby team-up promises more immersive car audio

You might not have to buy a Lucid Air or Mercedes to listen to spatial audio in your car. Dolby and Swedish firm Dirac are collaborating to demo more immersive in-car audio technology. The partnership melds Dirac’s optimization algorithms with Dolby Atmos support to deliver 3D sound as well as improve audio quality across the board. The combo can compensate for poor cabin acoustics (such as reflective surfaces and awkward speaker placement) while promising advanced sound staging normally reserved for home theaters.

The two companies are showcasing their teamwork in demo cars, but you may have to wait a while to hear it in a vehicle you can drive. The first car to take advantage of Dolby and Dirac tech is the Nio ET7. The electric sedan won’t come to Europe until later this year, and the Chinese brand has yet to commit to a North American expansion.

Still, the efforts might go some way toward democratizing Atmos and quality car audio. You might not need to buy a luxury car (or a pricey option package) to listen to spatial sound or otherwise enjoy the quality you normally get at home. Audio performance could be a particularly strong selling point as self-driving cars rise to prominence. If your car is going to be a lounge on wheels, you’ll probably want the speaker system to match.

HyperX’s Cloud Mix Buds makes managing multi-device audio a breeze

Wireless headphones have gotten better at connecting to multiple devices in recent years. But pairing can still be kind of a hassle, especially if you’re gaming on a range of devices including consoles, phones and PCs. But after testing out its new Clo…

Sony would love if you bought its $3,700 Walkman for over-the-top audiophiles

Are you the sort of music listener who’ll happily pay more for a set of earphones than you would on a nice computer? If so, Sony has the MP3 players for you. The company has released two ultra-high-end Walkman MP3 players aimed squarely at audiophiles. The headliner, the $3,700 NW-WM1ZM2 (pictured at left), mates an S-Master HX digital amp with “fine-tuned” capacitors, thick Kimber Kable (to link the amp to the headphone jack) and a 99.99 percent pure gold-plated, oxygen-free copper chassis — all of which supposedly contribute to “clear, expansive” output. Even the reflow soldering includes gold that purportedly boosts sound localization and widens the sound stage.

You can also expect more practical improvements from the Android-based player, including a larger five-inch (and finally 720p) display, a larger power supply and an improved upscaling algorithm for CD-quality (16-bit, 44/48kHz) audio. You’ll get 256GB of expandable storage for your tunes, WiFi streaming, a USB-C port and 40 hours of battery life when playing 96kHz FLAC audio. The ZM2 supports up to 32-bit, 384kHz audio in formats like MQA and WAV, so you’re more likely to be limited by your source material than your hardware.

Don’t worry if that feels excessive, as there’s also a lower-cost model… relatively speaking. The $1,400 NW-WM1AM2 (shown at right) offers much of the core functionality of the ZM2, but in an aluminum alloy body with ‘just’ a low-resistance oxygen-free copper cable. You’ll also have to make do with 128GB of expandable space.

Both Walkman models are available now. As with many devices aimed at audiophiles, there’s a question of whether or not the exotic components and materials will be noticeable in your listening experience. Moreover, you’re limited by the lowest common denominator in your setup. Even if you listen to songs that can take advantage of the design (Apple Music’s 24-bit, 192kHz hi-res lossless suddenly seems modest), you’ll have to find headphones or speakers that are up to the job. Both players are mainly aimed at wealthy music fans determined to maximize audio fidelity, even if they might not hear the difference.

Apple’s AirPods Max are back on sale for $449

While the AirPods Max are Apple’s most advanced headphones to date, they’re also the company’s most expensive. Normally priced at $549, all of the colors of the AirPods Max are on sale right now. Most of them are $100 off and down to $449, while currently the pink and the space gray models are $120 off and down to $429.

Shop AirPods Max at Amazon

These headphones will be most useful to Apple diehards as the combine the conveniences of the H1 chipset with remarkable audio quality and ANC. We gave them a score of 84 and found them to have excellent, balanced sound with Adaptive EQ and spatial audio support, plus ANC that’s strong enough to block out most surrounding noises. They have a uniquely “Apple” design, complete with aluminum earcups and a mesh headband, and it’s actually quite comfortable despite being on the heavier side. We also appreciate their reliable onboard controls: you can use the rotating crown to adjust the volume, and there’s a dedicated button that switches between ANC and Transparency mode.

Inside the AirPods Max is Apple’s H1 chipset, which means these headphones have all of the conveniences that the company’s wireless earbuds do. They’ll pair quickly with iPhones and other Apple devices, and you can switch seamlessly from taking a call on your iPhone to listening to music on your MacBook. The chip also powers hands-free Siri access, so you can ask the virtual assistant to do things for you without lifting a finger. Admittedly, they’re still high-priced headphones even when on sale — you could pick up the new Sony WH-1000XM5 for less — but the AirPods Max are a good choice for those that live within the Apple ecosystem.

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