BOOM September Issue | Page 47

Wireless These headphones are free of cords and cables, and can be used comfortably without worrying about cable length and tangling. Wireless headphones usually work on one of three major transmission technologies: radio frequency, infrared and Bluetooth. The first two require a dedicated base unit which connects to the source device and transmits the frequency to the headphones, while the third uses the popular Bluetooth technology and can be paired wirelessly with a wide range of smartphones, tablets and computers. RF headphones usually work over larger distances, while infrared headphones rely on line-of-sight, and Bluetooth has a 30m range limit in most cases. Pros: Better portability and more suitable for outdoor use. Also useful for home use when the source device is placed at a large distance, such as when watching TV or listening to music in the living room. Cons: Sound quality is usually not as good as wired headphones. Range issues and battery life can also create problems in the sound and listening experience. These are the main types of headphones you'll be looking at in the market, but if you're confused by some of the jargon you come across in the shops, don't worry. There are a few basic terms you should know about, and you can probably ignore the rest. You'll find most of these mentioned on e-commerce websites, or on the box of the set you're buying. Headphone Jargon Drivers The core components of any headphones, the drivers are used to convert the electrical signal fed to the headphones into an audible sound signal that can be perceived by the human ear. There are various types of drivers used in headphones, including the most commonly used moving coil (dynamic) drivers, balanced armature drivers, planar magnetic drivers and electrostatic drivers, among others. They use different technologies to power the sound, with some technologies offering better, more powerful sound than others. Dynamic drivers are used in all kinds of headphones, balanced armature drivers are general used in in-ear headphones due to the small size, while planar magnetic and electrostatic drivers are the largest and are usually used in built-for-home over-ear headphones. Some headphones, known as hybrids, use a combination of two drivers (most commonly a combination of dynamic and balanced armature drivers). Generally speaking, bigger drivers don't necessarily mean better as there are other factors as well, but they are a contributing factor, particularly for bass. However, it's best to audition headphones before buying, or read reviews to make sure the product is suited to you. Typically, earphones like the ones bundled with your phone will be around 15mm, while over-ear sets will be around 30-50mm. Closed- and open-back Headphones can be either closed or open at the back of the driver enclosure. Since a driver fires both into and away from your ear, an open-back headset will allow the sound to escape outside, while a closed-back headset will block the exit of the outward sound. There are pros and cons to both. Closed-back headphones prevent others from listening to what you're listening to and are therefore more suited TECH for public places as opposed to open-back headphones which leak sound and are perceived as inconsiderate to use in public. However, open-back headphones (like the ones pictured below) have a much more open sound, giving a more comfortable and realistic listening experience, while closed-back headphones sound more 'in-your-head'. Suitability depends on the purpose for which you need the headphones, and auditioning or reading reviews is recommended. Frequency response The fre