A headset is a headphone combined with a microphone. Used in call centers and by people in telephone-intensive jobs, headsets provide the equivalent functionality of a telephone handset with hands-free operation. Many people use headsets at the computer so they can converse and type comfortably. Headsets typically have only one speaker like a telephone, but also come with speakers for both ears.
Although headset can mistakenly be referred to as simply a headphone, it is now more commonly used to refer to a headphone with a microphone arm attached. This distinction is important as most headset developers have adapted to this terminology, improper reference may cause a lot of misunderstanding. Note that headphones are usually used for Audio/Music listening, whereas Headsets are designed for Communication.
The first-ever headset was invented in 1910, by a Stanford University student named Nathaniel Baldwin. However, Baldwin's design was ahead of his time, as he wasn't able to interest anyone in mass producing this innovative communication tool. Not until during the World War I did the US Army purchase 100 headsets for their pilots. Hence the early usage and markets for headsets were mainly for aviation purposes. In fact, Plantronics was started by two pilots, and their main goals were to develop headsets which are lightweight and comfortable for pilots and subsequently general users.
Headphones usually come in double earpiece design, whereas headsets can come in single-earpiece and double earpiece designs. Single earpiece Headsets are known as monaural headsets. However, double earpiece headsets comes in both stereo type or binaural type. Stereo refers to two channels of audio signal, one for each earpiece, and binaural headsets offer the same audio channel for both ear-pieces. Headphones are designed mainly for music listening, so most often they come in stereo version.
Professional users may choose to wear monaural headsets because they free up the users' other ear, so they can be more conscious of their work surroundings. Telephone headsets only come in Binaural type for double earpiece designs because telephone only offers single-channel input and output, so all double earpiece telephone headsets are Binaural.
However, for computer or other audio applications, where the sources offer two-channel output, stereo headsets are the norm. Telephone Headsets generally use 150 Ohm loudspeakers with a narrower frequency range, so sound outside the voice band is less audible to reduce background noise. Stereo computer headsets, on the other hand, use 32 Ω loudspeakers which have a much broader frequency range, and is more suitable of music listening.
The microphone arm of headsets come in external microphone type and transparent voicetube type. External microphone designs have the microphone housed in the front end of the microphone arm, inside a microphone capsule. Transparent voicetube designs are also called Internal Microphone design, meaning the microphone is housed near the arm-rotation mechanism. The sound from the user travels through the sealed transparent tube to the hidden microphone. Voicetube designs look better, and are considered professional based on pre-set norms; however when compared with an external microphone design, an external microphone headset usually has a much better performance. Voicetube headsets usually only come in the form of telephone headset or mobile headset, there are not any computer headsets using voicetube designs and there is no particular technical reason for this, it is probably purely the industry norm.
External microphone design also comes in two major types: omni-directional and noise-canceling. Noise-canceling microphone headsets use bi-directional microphone as elements. A bi-directional microphone's receptive field is, as its name suggests, two angles only. In fact, its receptive field is limited to only the front and the direct opposite back of the microphone. This will create an "8" shape field, and this design is the best method for only picking up sound from a close proximity of the user, meanwhile not picking up most surrounding noises. Bi-directional microphone works better than uni-directional microphone (single angle reception field) because uni-directional microphone also picks up some of the sound 90-degrees (both sides) to the desired angle. Omni-directional microphone picks up the complete 360-degree field, hence it is also the best receptive microphone but it also picks up most of the surrounding noises. In some instances, when a higher sensitivity is required for the microphone, or when the sound source is further away from the microphone, omni-direction microphone is the preferred choice. In fact, almost all voicetube designs employ an omni-directional microphone (since the sound source needs to travel through the voicetube before it reaches the microphone).
Standard headsets with the headband wearing over the head are known as over-the-head headsets. Headsets with headband going over the back of the user's neck are known as backwear-headset or behind-the-neck headsets. Headsets that are worn over the ear with a soft ear-hook are known as over-the-ear or earloop headset; these headsets do not have a headband. There are also headsets in the market which are designed so that users can change the wearing method by assembling and dis-assembling various parts, known as convertible headsets.
With the evolution of telecommunication technology, the applications for headsets are no longer military-focused. Business as well as consumer applications are the main target markets now. There are basically three main applications for headsets: (1) fixed-line telephone - PSTN/PABX) (2) computer - VoIP and (3) mobile phone usage.
Telephone headsets usually refers to headsets used to connect to a fixed-line telephone system, be it PSTN (general non-system telephones) or PABX (office system telephones). A telephone headset functions by replacing the handset of a telephone; hence it cannot operate on its own. All telephone headsets come in a standard 4P4C modular connector (commonly referred to as an RJ-9 connector), which is exactly the same as a telephone handset. By removing the handset and replacing it with the headset, users can talk on the phone without holding the handset. As research shows, many office workers suffer from Telephone Neck Syndrome (TNS) due to constantly squeezing the telephone handset with their neck and shoulder during conversations. So for work-safety and anti-insurance claim purposes, the ergonomics of headsets are a very hot topic right now.
When choosing a telephone headset, users should keep in mind that not all telephone headsets are directly compatible with all telephone models. Because headsets connect to the telephone via the standard handset jack, the pin-alignment of the telephone handset may be different from the default pin-alignment of the telephone headset. All telephone handsets connect to its telephone base-unit via a 4-pin cable; however, the alignment of those four pin differs across each brand or sometimes across each telephone model. That is why most professional headset brands offer adaptors for pairing the headset with the telephone. These are called Telephone Headset Adaptors or Pin-Alignment Configurators (ie. Accutone's C100 or C333).
For older models of telephones, the headset microphone impedance is very different from that of the original handset. Under such circumstances, users will need to purchase a telephone amplifier to pair with the telephone headset (ie. Plantronics' Vista M22, MX10 or Accutone's A20, A30). A telephone amplifier provides basic pin-alignment similar to a telephone headset adaptor, but it also offers sound amplification for the microphone as well as the loudspeakers. Most models of telephone amplifiers offer volume control for loudspeaker as well as microphone, mute function and headset/handset switching. Telephone Amplifiers must be powered, either through batteries or AC adaptors.
Some users are confused by a headset's quick disconnecting (QD) cable and its RJ-9 modular plug, thinking their headset has a unique connector which makes it impossible for them to connect one brand of headset with another brand's amplifier. This is not necessarily the case. Most professional-level telephone headsets come with a QD cable, so users can quickly disconnect their headset after a conversation and leave their desk for another quick task. However, a QD is designed for convenience only. Users should find that no matter how different or unique a QD is, the bottom part of a QD cable is usually a standard RJ-9 modular plug. The reason is because most telephone headsets are able to connect to a standard telephone handset jack, which is always a RJ-9 modular jack.
Although users can plug any type of telephone headset into any telephone amplifier, it does not guarantee functionality, since the headset pin-alignment may still be different from the pin-alignment of the headset-jack in the amplifier. But theoretically speaking, if users connect a telephone headset adapter (or pin-alignment configurator) as discussed above, all headsets can be paired to all amplifiers.
Computer headsets generally come in two connecting types, standard 3.5 mm & USB connection. General 3.5 mm computer headset comes with two 3.5 mm connectors, one connecting to microphone jack (line-in) and one connecting to speaker jack (line-out) of the computer. 3.5 mm Computer Headset connects to the computer via a soundcard - which converts the digital signal of the computer to analog signal for the headset. Depending on the quality of the soundcard, the sound quality of 3.5 mm connection generally is not as good as a USB connection. USB computer headset connects to the computer via USB ports, and the audio conversion occurs in the USB PCBA located in the headset or in the control unit of the headset.
Usually 3.5 mm headsets are much cheaper in pricing, and this is reflected in the quality of the material a developer chooses. For very basic communication, or entry level users, a 3.5 mm headset is more than sufficient. Connection is simple and compatibility is high. Virtually any device can be connected with a standard 3.5 mm jack, meaning users can connect the speaker (line-out) plug to a MP3 player or a CD Player with a 3.5 mm jack without any problems. Users can also connect the microphone (line-in) plug to any digital recording device with a 3.5 mm jack as well. However, the sound quality is marginal for these types of headset. Even coming from big brand names like Logitech, one cannot expect high-end quality from this type of product. A new feature has been seen recently that automatically switch the sound from speaker to headset, the function is referred to as Jetswitch
USB headsets are usually more expensive, but the sound quality is usually much better; not just in the actual sound quality of USB technology, but also in the choice of materials from headset developers. There are, however, actually two sub-types of USB headsets:(A) Headset with USB connection and (B) Direct USB headset.
Headset with USB connection refers to those computer headsets with a standard 3.5 mm headset bundled with a USB adaptor. One end of the USB adaptor is a standard USB plug, but the other end is a pair of 3.5 mm jacks where the 3.5 mm computer headset is connected. The benefit of using this type of solution is that users can just buy the USB adaptor to use with their existing 3.5 mm headset, or they can use their existing multimedia speakers or desktop microphone. By connecting the devices to the USB adaptor, users have a higher flexibility. However the down-side is that the sound quality of this type of solution is much lower than a standard Direct USB Headset, plus the adaptor and all the cables makes this solution very cumbersome. Brands offering this cheaper-end solution includes Philips, Logitech and Altec Lansing (now part of Plantronics).
Direct USB Headset usually has a digital volume controller which also includes the USB module, however some solutions have separated the controller and the USB module. This type of solution is usually offered in higher-quality design, as this direct connection minimizes the chance of interference as well as length of path; this is the preferred choice for users seeking top end sound quality. Users will find that this type of solution is usually priced a bit higher, but extra audio features like Digital Signal Processing (DSP) or noise canceling technology are very common. Brands offering these types of solutions include Plantronics, Jabra and Accutone.
With most newer Operating Systems (Microsoft Windows, Apple Mac OS X, Linux) USB Headsets are plug-and-play, and no drivers are required. However, depending on the extra features the headset offers, some may require extra software installation. In addition to sound quality, a benefit of any USB headset is Interactivity, meaning users in addition to getting audio signals from the computer, users can actually control the computer using the headset. There are some products in the market which users can use the USB headset to start up Skype, and control various functions of the Instant Messenger (IM) Application by only using the headset.
Mobile (Cellular) Phone Headsets are most often referred to as Mobile Handsfree. Most mobile phones come with their own handsfree in the form of a single earphone with a microphone module connected in the cable. However, as music-playing mobile phones are becoming the norm, most manufacturers will bundle stereo earphones with a microphone for MP3 listening. There are brands which offer mobile headset outside of the mobile phones developer. The main reason for this is either for better sound quality or higher convenience in the form of wireless solutions.
High quality mobile headsets come in both earbud-wearing style, as in the case of Jabra or Shure, and over-the-head-wearing style, as in Plantronics. Both types of headsets offer advantages, as earbuds are better in mobility and over-the-heads are more comfortable. Most after-market mobile headsets come in a standard 2.5 mm plug. So users have to purchase an additional adaptor for their mobile phones. Smartphones often use a standard 3.5 mm jack, so users may be able to directly connect the headset to it. However, brands like Sony Ericsson, Nokia or Motorola have very different headset jacks now. These adaptors are relatively cheap and can be purchased at any mobile accessories store. Users should be aware that they should bring their telephone to test the headset, as 2.5 mm plugs may still have some differences in its pin-setting, and are not 100% universal.
As for Wireless Mobile Headsets, most of them now use Bluetooth technology, as the advantage of using Bluetooth is that users do not need to add an extra transmitter in the mobile phone. Bluetooth audio transmission is relatively stable now, and most headsets are compatible with most mobile phones. The version 2.0 is the most compatible version now, with features like stereo transmission for music listening in A2DP profile.
Wireless headsets are quickly becoming a new trend for both business and consumer communications. There are a number of solutions for wireless, and they usually differ according to application and power-management.
DECT(Digital Enhanced Cordless Telecommunication] is one the most common standards for cordless telephones. It uses 1.88 to 1.90 GHz RF (European Version) or 1.92 to 1.93 GHz RF (US Version), as the frequency bandwidth. Different countries have regulations for the bandwidth used in DECT, but most have pre-set this band for wireless audio transmission. The most common profile of DECT is GAP (Generic Access Profile), which is used to ensure common communication between base station and its cordless handset. This common platform allows communication between the two devices even if they are from different manufacturers. For example, a Panasonic DECT base-station theoretically can connect to a Siemens DECT Handset. Based on this profile, developers such as Plantronics or Jabra have launched wireless headsets which can directly pair with any GAP-enable DECT telephones. So users with a DECT Wireless Headset can pair it with their home DECT phones and enjoy wireless communication.
Because DECT specifications are different between countries, developers who use the same product across different countries have launched wireless headsets which use 2.4GHz RF as opposed to the 1.89 or 1.9 GHz in DECT. Almost all countries in the world have the 2.4 GHz band open for wireless communications, so headsets using this RF band is sellable in most markets. However, the 2.4 GHz frequency is also the base frequency for many wireless data transmission, ie. WLAN, Wi-Fi, Bluetooth..., the bandwidth may be quite busy, so using this technology may be more prone to interference.
Because 2.4 GHz Wireless Headsets cannot directly "talk" to any standard cordless telephones, an extra base-unit is required for this product to function. Most 2.4 GHz Wireless Headsets come in two units, a wireless headset and a wireless base-station, which connects to your original telephone unit via the handset jack (similar to how telephone headsets are connected to a fixed-line telephone suggested in section 1 of this article). The wireless headset communicates with the base-station via 2.4 GHz RF, and the voice signals are sent or received via the base unit to the telephone unit. This type of solution is more primitive as more connection is required, however it is also highest in compatibility, as it will fit with almost all types of telephones in the market. An extra note is that some solutions will also offer an automatic Handset Lifter, so the user can wirelessly lift the handset off the telephone by pressing the button on the wireless headset. Jabra (previously known as GN Netcom) has some excellent solutions in 2.4 GHz wireless products.
When choosing a Bluetooth headset users should be aware that bluetooth headsets come in different types as well. Standard bluetooth headset's using version 1.0 or 1.1 are often a single-side monaural earpiece, which can only access the Headset/handsfree profile of bluetooth. This type of headset will not be able to play music wireless via your mobile phone, even if your mobile phone has MP3 playing capability. If you plug in a standard corded headset to your phone, you can hear music, but the wireless profile will not allow the music to be played wirelessly. For users who are looking for a stereo-music playing bluetooth headset, they should look for a headset with the A2DP profile-equipped headset. Users should note that some A2DP-equipped headsets will automatically de-activate the microphone function during music-listening, so if these headsets are paired to a computer via bluetooth connection, the headset may either disable the stereo function or the microphone function.
Some developers have offered complete desktop solutions using Bluetooth technology. With a base-station that connects via cables to the fixed-line telephone and also the computer via soundcard, users with any bluetooth headset can pair their headset to the base-station, hence enabling them to use a single headset for both fixed-line telephone and computer VoIP communication. This type of solution, when used together with a multiple-point bluetooth headset enables user to use a single bluetooth headset to communicate in Telephone/Computer/Mobile.