Headset (audio)

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Military telephone headset from World War I

A headset combines a headphone with a microphone. Headsets are made with either a single-earpiece (mono) or a double-earpiece (mono to both ears or stereo). Headsets provide the equivalent functionality of a telephone handset but with hands-free operation.[1] They have many uses including in call centers and other telephone-intensive jobs and for anybody wishing to have both hands free during a telephone conversation.

Types of headset[edit]

Bluetooth ear phone.

Headsets are available in single-earpiece and double-earpiece designs. Single-earpiece headsets are known as monaural headsets. Double-earpiece headsets may support stereo sound (two slightly different channels of audio signal, one for each earpiece), or use the same audio channel for both ear-pieces.

Monaural headsets free up one ear, allowing interaction with others and awareness of surroundings. Telephone headsets are monaural, even for double-earpiece designs, because telephone offers only single-channel input and output.

For computer or other audio applications, where the sources offer two-channel output, stereo headsets are the norm; use of a headset instead of headphones allows use for communications (usually monaural) in addition to listening to stereo sources. Telephone headsets generally use 150-ohm loudspeakers with a narrower frequency range than those also used for entertainment.[2] Stereo computer headsets, on the other hand, use 32-ohm speakers with a broader frequency range.

Microphone style[edit]

The microphone arm of headsets may carry an external microphone or be of the voicetube type. External microphone designs have the microphone housed in the front end of the microphone arm. Voicetube designs are also called internal microphone design, and have the microphone housed near the ear-piece, with a tube carrying sound to the microphone.

Noise-cancelling and directional characteristics[edit]

Most external microphone designs are of either omnidirectional or noise-canceling type.

Noise-canceling microphone headsets use a bi-directional microphone as elements. A bi-directional microphone's receptive field has two angles only. Its receptive field is limited to only the front and the direct opposite back of the microphone. This create an "8" shape field, and this design is the best method for picking up sound only from a close proximity of the user, while not picking up most surrounding noises.

Omni-directional microphones pick up the complete 360-degree field, which may include much extraneous noise.

Different styles of headsets[edit]

Standard headsets with a headband worn over the head are known as over-the-head headsets. Headsets with headbands going over the back of the user's neck are known as backwear-headsets or behind-the-neck headsets. Headsets worn over the ear with a soft ear-hook are known as over-the-ear headsets or earloop headsets. Convertible headsets are designed so that users can change the wearing method by re-assembling various parts.

Smart headsets[edit]

Smart headsets incorporate smart headset technology analogous to that of a smartphone. As of date, few models of smart headsets are in production. Smart headsets usually perform a verity of functions such as, but not limited to: monitoring fitness, monitoring movement, storing/playing music or audio files, and receiving phone calls. Many companies are looking to develop software for real time translating via. smart headsets. As of yet there is no clear boundary on what is or is not a "smart headset".[citation needed]

Telephone headsets[edit]

A user wearing a monoaural Plantronics headset. (Nov 2012)

Telephone headsets connect to a fixed-line telephone system. A telephone headset functions by replacing the handset of a telephone. Headsets for standard corded telephones are fitted with a standard 4P4C commonly called an RJ-9 connector. Headsets are also available with 2.5mm jack sockets for many DECT phones and other applications. Cordless bluetooth headsets are available, and often used with mobile telephones. Headsets are widely used for telephone-intensive jobs, in particular by call centre workers. They are also used by anyone wishing to hold telephone conversations with both hands free.

Headset compatibility and pin alignment

Not all telephone headsets are 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. To ensure a headset can properly pair with a telephone, telephone adapters or pin-alignment adapters are available.[3] Some of these adapters also provide mute function and switching between handset and headset.

Telephone amplifiers

For older models of telephones, the headset microphone impedance is different from that of the original handset, requiring a telephone amplifier to impedance-match the telephone headset. A telephone amplifier provides basic pin-alignment similar to a telephone headset adapter, 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 switching between handset and headset. Telephone amplifiers are powered through batteries or AC adapters.

Quick disconnecting cable

Most telephone headsets have a Quick Disconnect (QD) cable, allowing fast and easy disconnection of the headset from the telephone without having to remove the headset.

Computer headset[edit]

Front view of SteelSeries Siberia Neckband gaming headset. The microphone is on the left earcup. With standard 3.5 mm TRS connectors

Computer headsets generally come in two connection types: standard 3.5 mm & USB connection. General 3.5 mm computer headsets come with two 3.5 mm connectors: one connecting to the microphone jack (line-in) and one connecting to the speaker jack (line-out) of the computer. 3.5 mm computer headsets connect to the computer via a soundcard, which converts the digital signal of the computer to an analog signal for the headset. USB computer headsets connect to the computer via a USB port, and the audio conversion occurs in the headset or in the control unit of the headset.

Mobile phone headsets[edit]

Mobile (cellular) phone headsets are often referred to as handsfree. Most mobile phones come with their own handsfree in the form of a single earphone with a microphone module connected in the cable. For music-playing mobile phones, manufacturers may bundle stereo earphones with a microphone. There are also third-party brands which may provide better sound quality or wireless connectivity.

High quality mobile headsets come in a range of wearing-styles, including behind-the-neck, over-the-head, over-the-ear, and lightweight earbuds. Some aftermarket mobile headsets come with a standard 2.5 mm plug different from the phone's audio connector, so users have to purchase an adapter. A USB headset for a computer also cannot be directly plugged into a phone's or portable media player's micro-USB slot. Smartphones often use a standard 3.5 mm jack, so users may be able to directly connect the headset to it.

Many wireless mobile headsets use Bluetooth technology, supported by many phones and computers, sometimes by connecting a Bluetooth adapter to a USB port. Since version 1.1 Bluetooth devices can transmit voice calls and play several music and video formats, but audio will not be played in stereo unless the cellphone or media device, and the headset, both have the A2DP profile.

Wireless headsets[edit]

Wireless headsets are quickly becoming a new trend for both business and consumer communications. There are a number of wireless products, and they usually differ according to application and power-management.

DECT wireless headsets[edit]

Digital Enhanced Cordless Telecommunications (DECT) 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). 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 Generic access profile (GAP), 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, Jabra or Accutone have launched wireless headsets which can directly pair with any GAP-enabled DECT telephones. So users with a DECT Wireless Headset can pair it with their home DECT phones and enjoy wireless communication.

2.4 GHz wireless headsets[edit]

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, i.e. Wireless LAN, Wi-Fi, Bluetooth..., the bandwidth may be quite crowded, 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. 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. Some products 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.

Bluetooth wireless headsets[edit]

A typical Bluetooth headset.

Bluetooth device is widely used for short-range voice transmission. While it can be and is used for data transmission, the short range (due to using low power to reduce battery drain) is a limiting factor. A very common application is a hands-free Bluetooth earpiece for a phone which may be in a user's pocket.

Some Bluetooth headsets are designed for playing music and answering phone calls[4]
A stereo Bluetooth headset.

There are two types of Bluetooth headset. Headsets using Bluetooth 1.0 or 1.1 often have a single monaural earpiece, which can only access Bluetooth's headset/handsfree profile. Depending on the phone's operating system, this type of headset will either play music at a very low quality (suitable for voice), or will be unable to play music at all. Headsets with the A2DP profile can play stereo music with acceptable quality.[5] Some A2DP-equipped headsets automatically de-activate the microphone function while playing music; if these headsets are paired to a computer via Bluetooth connection, the headset may disable either the stereo or the microphone function.

Bluetooth wireless desktop devices[edit]

Desktop devices using Bluetooth technology are available. 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, enabling them to use the same headset for both fixed-line telephone and computer VoIP communication. This type of device, when used together with a multiple-point Bluetooth headset, enables a single Bluetooth headset to communicate with a computer and both mobile and landline telephones.

Some Bluetooth office headsets incorporate Class 1 Bluetooth into the base station so that, when used with a Class 1 Bluetooth headset, the user can communicate from a greater distance, typically around 100 feet compared to the 33 feet of the more usual Class 2 Bluetooth headset. Many headsets supplied with these base stations connect to cellphones via Class 2 Bluetooth, however, restricting the range to about 33 feet.

History[edit]

The headset was invented in 1910, by a Stanford University student named Nathaniel Baldwin. Baldwin was not able to interest anyone in mass-producing this communication tool. Not until World War I did the US Army purchase 100 headsets for their pilots.[6] Hence the early uses and markets for headsets were mainly for aviation. Plantronics, still a large manufacturer of headsets, was started by two pilots,[7] whose initial goal was to develop headsets which were lightweight and comfortable for pilots.

References[edit]

  1. ^ "Definition of Headset". PC Magazine. Retrieved 2010-05-27. 
  2. ^ "Telephone Headset". Retrieved 2010-05-27. 
  3. ^ "adapters". Retrieved 2010-05-27. 
  4. ^ "Arctic Sound P311 Bluetooth Wireless Headset Review" Retrieved 28/9/2012
  5. ^ "Bluetooth A2DP Explained by PC Authority"
  6. ^ "Ruin Followed Riches for a Utah Genius". Retrieved 2010-05-27. 
  7. ^ "About our Heritage". Plantronics. Retrieved 2010-05-27.