In early powered radios, the headphone was part of the vacuum tube's plate circuit and carried dangerous voltages. It was normally connected directly to the positive high voltage battery terminal, and the other battery terminal was securely grounded. The use of bare electrical connections meant that users could be shocked if they touched the bare headphone connections while adjusting an uncomfortable headset.
However, the Bose 700 earphones have a much slimmer profile when folded up, and they have a few updated elements, including more integration with digital assistants, touch controls, and sensors for Bose’s “augmented reality” apps. Bose has kept some of the best-loved features from its older models as well, such as adjustable levels of noise cancellation, a monitoring mode to let in sound from your environment, and an advertised 20-hour battery life. According to Bose, call quality is improved as well, though CR doesn’t test call quality in headphones.
However, most people won’t be able to hear the difference if they’re older than 24, have some form of noise-induced hearing loss, or are in the presence of outside noise. For this reason, we recommend wireless Bluetooth headphones for those commuting, or in noisy situations. If you’re listening primarily at home at the computer—get a set of wired headphones.
The moving coil driver, more commonly referred to as a "dynamic" driver is the most common type used in headphones. It consists of a stationary magnet element affixed to the frame of the headphone, which sets up a static magnetic field. The magnet in headphones is typically composed of ferrite or neodymium. A voice coil, a light coil of wire, is suspended in the magnetic field of the magnet, attached to a diaphragm, typically fabricated from lightweight, high-stiffness-to-mass-ratio cellulose, polymer, carbon material, paper or the like. When the varying current of an audio signal is passed through the coil, it creates a varying magnetic field that reacts against the static magnetic field, exerting a varying force on the coil causing it and the attached diaphragm to vibrate. The vibrating diaphragm pushes on the air to produce sound waves.
Will Greenwald has been covering consumer technology for a decade, and has served on the editorial staffs of CNET.com, Sound & Vision, and Maximum PC. His work and analysis has been seen in GamePro, Tested.com, Geek.com, and several other publications. He currently covers consumer electronics in the PC Labs as the in-house home entertainment expert, reviewing TVs, media hubs, speakers, headphones, and gaming accessories. Will is also an ISF Level II-certified TV calibrator, which ensures the thoroughness and accuracy of all PCMag TV reviews.
The Astro Gaming A50 emerged in 2012 as the wireless follow-up to the excellent A40. Seven years later and four generations on, they remain the gold standard for gaming audio. With an ability to faithfully reproduce 7.1 channel surround sound through just two earcups, gamers will get critical 3D audio for all of their favorite console titles whether it’s from an Xbox One or a PlayStation 4. Wireless audio can lead to an unacceptable amount of lag, which often sends gamers in search of wired models, but here too, the A50 manage to beat expectations.