1. Types of headphones Headphones are a pair of small loudspeakers, or less commonly a single speaker, held close to a user's ears and connected to a signal source such as an audio amplifier, radio, CD player or portable media player. They are also known as stereophones, headsets or, colloquially cans. The in-ear versions are known as earphones or earbuds. In the context of telecommunication, the term headset is used to describe a combination of headphone and microphone used for two-way communication. Choice of headphone –determined by need 4 categories: circumaural supra-aural Earbud In-ear

2. Circumaural headphones Also called full size headphones have circular or ellipsoid earpads that encompass the ears completely surround the ear fully seal against the head to attenuate any intrusive external noise Because of their size, circumaural headphones can be heavy some sets which weigh over 500 grams (1 lb) Good headband and earpad design is required to reduce discomfort

3. Supra-aural headphones Supra-aural headphones have pads that sit on top of the ears-around them bundled with personal stereos during the 1980s smaller and more lightweight than circumaural less attenuation of outside noise Ear buds (intra-concha) rest in the bowl of the ear, outside the ear canal, though a portion might extend into the canal typically come with iPods and other portable audio players.

4. In ear Earbuds or earphones are headphones of a much smaller size that are placed directly outside of the ear canal, but without fully enveloping it. generally inexpensive favored for their portability and convenience type bundled with personal music devices HEALTH ISSUE Due to their inability to provide any isolation they are often used at higher volumes which increases the risk of hearing-losshearing-loss Probably the most popular type of headphones, they are small, lightweight, can easily be transported, and are normally relatively cheap Ear bud headphones are not particularly efficient headphones fit loosely outside the ear - some of the audio you are listening too gets lost and leaks sounds from the outside world also make it into your ear distortion in the audio reproduction. not provide a significant upgrade in performance or comfort.

5. Sound isolating earphonesSound isolating earphones - also known as Ear Canal HeadphonesEar Canal Headphones In-ear monitors (also known as IEMs or canalphones) are earphones that are inserted directly into the ear canal providing isolation from outside noise. Canalphones offer portability similar to earbuds, and also act as earplugs to block out environmental noise There are two main types of IEMs: universal and custom Universal canalphones provide one or more stock sleeve size(s) to fit various ear canals, which are commonly made out of silicone rubber, elastomer, or foam, for noise isolationsiliconeelastomer Many come with additional earpieces (canal tips) of varying sizes to ensure a proper fit. Custom canalphones are fitted to the ears of each individual. Castings of the ear canals are made and the manufacturer uses the castings to create custom-molded silicone rubber or elastomer plugs that provide added comfort and noise isolation More expensive resell value is very low

6. small rubberised ear-tip sleeve small, lightweight and very portable. they isolate your ear from the outside world by upto minus 20dB originally developed for musicians to protect their hearing whilst being able to listen to the rest of the band at a sane volume level. HEALTH ISSUES Many people use sound isolating earphones while exercising, but some comment that they can hear any impact on the body as a dull thud inside their ear. This can also occur if the earphone lead is knocked. This is caused by the fact that the sound isolating material over the tip is transmitting the sound more directly to the ear drum. dangerous if listening while running, cycling, skiing or any activity where you need awareness of the people and objects around you best quality sound for every day portable use you are travelling or on the move the lack of distortion added by the active electronics in a noise cancelling headset

7. Head set equivalent functionality of a telephone handset with hands-free operation most common uses for headsets are in console or PC gaming, Call centres and other telephone-intensive jobs made with either a single-earpiece (mono) or a double-earpiece (mono to both ears or stereo) microphone type where the microphone is held in front of the user's mouth, or a voicetube type where the microphone is housed in the earpiece and speech reaches it by means of a hollow tube. Telephone headsets headset functions by replacing the handset of a telephonehandset All telephone headsets come in a standard 4P4C commonly called an RJ-9 connector4P4C

8. Wireless headphones advantage that you are no longer restricted by cables with no restrictions on your movement. generally don't sound quite as good as equivalently priced wired headphones The audio gets processed by electronics in the base unit, gets transmitted via radio signal (or in some cases infra-red) and then is converted back to an audio signal by the headset.-adds extra noise to the audio signal For example if you compare a pair of Sennheiser RS140 wireless headphones against a pair of similarly priced Sennheiser HD595 wired headphones there is a noticeable difference in audio qualitySennheiser RS140 wireless headphonesSennheiser HD595 wired headphones detect a background hiss with the wireless pair during quiet passages of music but don't go expecting audiophile quality sound. The best wireless headphones we have heard are Sennheiser's RS wireless headphone range - see the Sennheiser RS110, RS120, RS130 and RS140 modelsbest wireless headphones The open back design of the RS130 gives a more open soundstage and a more natural sound as the earcups reflect less sound back into the ear.

9. Noise cancelling headphones reduce the perceived noise from outside with the clever use of small microphones located inside the earpiece and active electronics within the headset. The basic principle is that the noise signal for the outside world is inverted and then summed with the signal from the audio source- ambient noise from outside is effectively cancelled out are particularly effective with reducing low frequencies work very well at cancelling out the constant low down booming noise created inside an aircraft cabin by jet engines or the roar from fans in a computer room, but will not work so well at reducing the noise of a child screaming in the seat next to you on the train to work in the morning. The active electronics inside a noise cancelling headphone set require power (i.e. batteries) to run in noise cancelling mode passive' methods to block out the external sounds and the audio signal does not undergo any electronic processing recommend sound isolating headphones orclosed back full size headphones in preference to noise cancelling headphonessound isolating headphonesclosed back full size headphonesnoise cancelling headphones

10. OPEN BACK HEADPHONES designed to allow sound out through the back of the earcup. open soundstage, or natural. One reason for this is that there are less reflections than a closed back as providing a more accurate sound than the closed back variety The best audiophile grade sound is able to leak out and people nearby can hear the sound made by the earphone speakers not normally suitable for use in public places lack of isolation from external noise

11. : Closed Back Headphones reduce the effect of external noise to keep the noise made by the headphone drivers from leaking out design are DJ and studio monitoring. semi air tight earcups that enclose the ear ear cups reflect and resonate the sound made by the headphone drivers. The reflection of sound waves can cause closed back headphones to sound ‘boxy' and enclosed (especially on cheaper models) prevent bass leakage

12. On ear Also called supra-aural generally lighter than over-the- ears models don't press on the sides of your head--they press upon the ears them more comfortable for long listening session allow more ambient sound to enter open and closed versions adjustable strap that fits over Some can be folded for storage and come with carrying pouches.

13. Sports-style on-ear Also called supra-concha a good choice when you'll be engaged in a strenuous activity or exercise are supported by a bracket that passes around the back of the head generally radiate sound forward toward the ear canal rather than sideways directly into the ear canal Headphones for iPods and smart phones headphones have a microphone and small controls on the cord that let you control basic music player functions such as play and pause and connect and disconnect phone calls offer better sound quality that is more-suited to music.

14. Wireless headphones once rare, are now increasingly common, and typically use RF, infrared (IR), or Bluetooth wireless technologies. battery-powered headset and an AC- powered transmitter that connects to your audio or video gear RF models can transmit signals through walls and floors, so you don't have to be near your sound system listen to it in other rooms or even outdoors subject to interference from other devices, such as cordless phones and microwave ovens, that operate on the same frequencies often 900MHz or 2.4GHz Wireless headphones that use infrared technology, much like a TV remote, require a direct line of sight to the transmitter. Bluetooth is a type of digital spread-spectrum technology, and the typical model has an operating range of about 30 fee Bluetooth technology used in headphones (and other hi-fi audio uses) should employ the A2DP (Advanced Audio Distribution Profile) or "advanced audio" feature, rather than the narrow-band voice-quality mode used for wireless cell phone headsets

15. Active noise-reduction headphones closed design that fit tightly over your ears or inside the ear canal will block some noise by creating a seal. This is called passive noise reduction Models with active noise-canceling technology go a step further. These battery-powered headphones use tiny microphones to monitor noise frequencies, and then produce those same frequencies out of phase in an effort to cancel them most effective noise reduction in models that combined passive noise blocking with active noise cancellation. these will work without batteries