If you don't know your woofers from your tweeters, or you're baffled by technology, let us help you out! This handy jargon buster has been designed to demystify some of the most common hi-fi and home cinema terms. We've tried to explain some of the more exotic functions and facilities you might encounter on this site in layman's terms. We hope you'll find it useful.

1080p
This is the highest of the high, so to speak, being the best quality High Definition standard. Also known as ‘True HD’ or ‘Full HD’. Blu-ray and HD DVD discs offer such pretty pictures, although not all screens can accept them. The number ‘1080’ represents the 1,080 lines of vertical resolution, progressively scanned (see entry). The term usually assumes a widescreen aspect ratio of 16:9, implying a horizontal resolution of 1920 pixels. This creates a frame resolution of 1920×1080, or 2,073,600 pixels in total.

AAC (Advanced Audio Coding)
A popular digital audio encoding system that compresses data files for greater storage capacity – think of the music tracks stored on an iPod and you’re on the right track. AAC is similar to MP3, but offers superior quality and DRM support. AAC is the preferred coding system of Apple, so, for example, you’ll find tracks on iTunes encoded this way. A typical files size is 4MB.

Amplifier
Pretty much does what it says on the tin. In hi-fi terms this is an electronic device that amplifies or boosts the signal from a source component to a required volume. Also see Pre-amplifier and Power amplifier.

Analogue
For hi-fi buffs this refers to a way of recording and its related playback. So analogue should bring to mind images of turntables and tape recorders (and men with long beards) as opposed to portable MP3 devices, compact disc and DVDs. An analogue recording is one where the original audio signal and its corresponding waveform are modulated onto a physical media or substrate, such as the groove of a record. A physical quality in the medium (e.g. the shape of a record groove) is directly related or analogous – geddit – to the physical properties of the original sound's waveform. See Digital.

Analogue tuner
A device – normally integrated into the screen or a set-top box – that allows one to receive conventional TV stations, e.g. BBC1. All systems preceding digital transmission, such as NTSC, are analogue television systems. This older television broadcast signal is being phased out in the coming years – meaning analogue tuners will be useless. It will be replaced with a ‘digital’ signal.

Aspect ratio
The displayed width of an image divided by its height. A bit too much like maths? Okay does your picture look square or more like a letterbox? These are the two main aspect ratios around - the traditional 4:3 and its modern 16:9 (1.78:1) successor, used in HD television or the cinema. Conversion between formats can be accomplished by either cropping the image to fit the receiving format's ratio or adding black bars (the letterbox we spoke of earlier) to retain the original format's ratio.

Bass
How low can you go! Sorry. This is the lowest part of the frequency range, which is reproduced by woofers and subwoofers in loudspeakers. The scary rumbling often heard in home cinema demonstrations is a classic example of extreme bass.

Bi-wiring or bi-wired
A simple and cost effective way to improve the sound of your system or simply a complex version of the Emperor’s New Clothes: the jury is always out on this one. Bi-wiring is essentially a bewildering way of connecting speakers to amps, which is said to improve sound quality. The technique makes use of the two sets of speaker terminals commonly found on the rear of loudspeakers, and keeps high notes separate from mid/bass frequencies in the cable runs. This is meant to keep the respective frequency signals cleaner as they don’t mix with each other.

Bit and bit rate
A bit is the smallest component of a digitized musical signal. Compact disc, for example, is made up of 16 of these bits. A bit rate measures the speed of this data when it is transferred. Also used as a measure of quality for digital music, where the greater the Kbps or Mbps the superior the sound. See Digital.

Blu-ray disc (BD)
Blu-ray is a high-density optical disc format for the storage of digital information. Or in other words, something a bit like a DVD, but a whole lot better. DVD, turbo-charged. When properly implemented it offers superior image and sound quality over DVD. The format was developed to enable recording, rewriting and playback of high-definition video (HD), as well as storing large amounts of data. The format offers more than five times the storage capacity of traditional DVDs – up to 50GB on a dual-layer disc. Named after the blue-violet laser used to read the new discs, it is backed by Sony, Pioneer, Samsung and Apple amongst others.

Brightness
This is the amount of light that is emitted from any screen or projector and perceived by the eye. Brightness of screens is measured in cd/m squared, while for projectors it is measured in ANSI (American National Standards Institute) lumens. For both, the brighter the model the higher the rating. Remember, as with power in an amplifier, the biggest number doesn’t always equate to the best performance. Equally, if a TV cannot deliver a bright image, you’ll need a dark room, and this isn’t always possible.

Colour
The more colours a screen can produce, the more natural the image will appear. Plasma screens create colours by combining red, green and blue light. LCD screens create colours by removing colours from white backlight. Plasma’s additive process tends to work better, producing 90 per cent of the available colour spectrum, compared to around 75 per cent for LCD screens.

Component technology
The highest quality analogue video connection available. It is a method of connecting any video source - think DVD player or games console – to a screen or video projector. It cannot carry an audio signal. The component connection splits a picture into three channels. Consequently, component cables comprise three phono-type (or RCA) sockets, which are coloured green, blue and red. Has now been overtaken by HDMI connections in the quality (and convenience for that matter) stakes.

Contrast ratio
This is the difference between the lightest and darkest content that a screen or projector is capable of producing. A high contrast ratio is a desired aspect of any display, but with the various methods of measurements, remarkably different measured values can sometimes produce similar results. Remember that the contrast ratio promoted in marketing literature is always measured under the optimum condition of a room in total darkness. In typical viewing situations the contrast ratio is significantly lower, making it harder to distinguish between different devices with very high contrast ratios.

Crossover
The part of a loudspeaker that splits the incoming audio signal into separate frequency bands, and then sends these signals to specific drivers, such as the tweeter or woofer. They have a huge influence over the final sound of a loudspeaker design.

DAB
Digital Audio Broadcasting. A digital radio transmission that gives a clearer signal, greater selection of radio stations, and wonderful ease of access. What’s more, as well as sound, this technology allows the broadcast of station information and EPG. Look out for DAB+ technology, which offers superior sound. Sadly there won’t be any commercial broadcasts for at least five years!

DAC (audio)
Digital to Analogue Converter. Used in CD players and other digital hi-fi or home cinema components to change digitized information back into an analogue waveform that the amplifier and speakers can process.

DAC (Video)
Digital-to-Analogue Converter. A bit like a mini computer. DACs are at the beginning of the signal chain, which makes them very important to system performance. Video signals from a digital source, such as a DVD player, must be converted to analogue form if they are to be displayed on an analogue monitor. All new flat screens incorporate either a DVi or HDMI connection, bypassing these devices and sending the signal directly to the screen.

Digital
Any system that represents analogue signals as streams of numerically encoded data. Think of all those green bits in the Matrix. Digital systems use individual values (often electrical voltages) representing numbers for input, processing, transmission, storage, or display, rather than a continuous spectrum of values, as in an analogue system.

Digital tuner
A digital tuner, such as those often integrated into screens, receive signals via airwaves, satellite or cable, and translates them into a signal the device can display. For example, with digital TV, a digital tuner receives sound and pictures from the broadcaster in ‘bits’ of information and turns this signal back into pictures and sound.

Dimensions
How big is yours? Dimensions of a component normally excluding any stand, bracket or detachable speakers. 

DivX
DivX is a brand name of products created by DivX Inc., which have become popular due to their ability to compress lengthy video segments into small sizes while maintaining relatively decent visual quality. It is commonly associated with burning or ripping audio or video material onto a hard disk. Many newer ‘DivX Certified’ DVD players are able to play DivX encoded movies.

Dolby® Digital
This is the technology that puts the cinema into 'home cinema'. When a bullet whizzes across your front room, thank Dolby. Essentially it is a digital audio format that delivers surround sound replay, via a 5.1 speaker system. It is the designated audio standard for DVD worldwide. Dolby Digital is also the preferred multichannel audio standard for direct broadcast and digital cable systems.

Dolby® Digital EX
Dolby Digital EX takes the Dolby Digital 5.1-channel setup one step further with an additional centre surround channel (reproduced through one or two speakers) for extra dimensional detail and an enveloping surround sound effect.

Dolby® Pro Logic
Dolby Pro Logic was the foundation for multichannel home cinema, being the consumer version of the original Dolby multichannel analog film sound format. In the good 'ol days, when a Dolby Surround soundtrack was produced, four channels of audio information — Left, Centre, Right, and Mono surround — were matrix-encoded onto two audio tracks. These two tracks were then carried onto sources such as videotapes — remember them? — from which decoding by Dolby Pro Logic® recreated the original four-channel surround sound experience. The quality is limited, most notably by the mono, reduced bandwidth signal to the rear effects speakers.

Dolby® Pro Logic II, Dolby Pro Logic IIx
and Dolby Pro Logic IIz
Like Pro Logic (above), Pro Logic II turns a properly encoded two channel source into a full blown 5 channel signal. Improvements over the original Pro Logic include better channel separation and a full bandwidth, stereo signal to the rear speakers. The IIx version offers 6.1- or 7.1- channel playback. This is taken further still with IIz. It expands a 5.1 signal to 7.1 or even 9.1 with front height speakers.

Dolby® TrueHD
Dolby® TrueHD is Dolby’s next-generation technology developed for High Definition media. Dolby TrueHD delivers a sound that is bit-for-bit identical to the studio master. The 100 percent lossless coding technology offers up to 18Mbps bit rate and supports up to eight full-range channels of 24-bit/96 kHz audio. It is also HDMI compliant. Really rather good.

Driver
Another way to describe the round cones in a loudspeaker that create sound. For those that care, these mechanical devices push air in a pistonic manner to create sound waves.

DTS
Another multi-channel decoding format, similar to Dolby Digital, that delivers surround sounds in the home.  Often felt to have a slight edge over Dolby in terms of performance, thanks to an enhanced dynamic range and improved frequency response.  DTS uses higher data rates (1.5 Mbit/sec or 754 kbit/sec, which are almost twice to four times higher) to encode the 5.1 channels of surround sound information than Dolby Digital (448 kbit/sec or 384 kbit/sec).  It's hard to tell the difference, to be honest, and you'll always find both decoders on most machines.

DTS-HD
A next generation surround sound technology that is capable of delivering audio bit-for-bit identical to that of the studio master.  DTS-HD offers audio at super high variable bit rates - up to 24.5 mega-bits per second (Mbps) on Blu-ray discs and 18.0 Mbps on HD-DVD - that are significantly higher than standard DVDs.   It can offer audio at 7.1 audio channels at 24-bit/96kHz that are identical to the original. Another great piece of technology, similar to Dolby® TrueHD.

Dual-format DVD players
Players that can play both Blu-ray and HD DVD discs.   So far these haven't quite been the Holy Grail they sound like, due to some limitations replaying one or both formats.

DVD-A
A ‘next generation’, extremely high quality audio system Digital Versatile Disc-Audio uses a DVD’s superior storage capacity to offer a sonic improvement over conventional CD replay. Not only can it deliver stereo at 24-bit/192kHz quality, but also surround sound recordings in 24-bit/96kHz. Sadly, it never really caught on and there is extremely limited software availability.

DVI
The Digital Visual Interface (DVI) is a video interface standard designed to maximize the visual quality of digital display devices like flat screens or projectors. As a high quality, picture only connection it sends the signal uncompressed from a DVD player to a screen. It is available in A (Analogue), D (Digital) and I (Integrated – both A and D) versions. DVI-D or DVI-I sockets can be part of the requirement for High Definition TV.

DVD recorders
These burn programmes onto recordable DVDs, offering a more durable and compact alternative to VHS tapes.

Dynamics
The dynamics of a system refer to its reproduction the quietest and loudest parts of a piece of music. A highly dynamic system can go from extremely quiet to extremely loud as swiftly and easily as Lewis Hamilton.

EPG (Electronic Programme Guides)
These are found on Freeview units and simply list programmes on all the TV channels – usually for seven days. It makes programming a doddle.

Freeview
This is digital TV for those who don't want to see large chunks of cash disappear from their bank account every month. It gives a great choice of free digital channels, and is available built-in to some screens and DVD recorders, or as a separate box.

Freeview HD
Freeview HD gives up to 5 times the detail of ordinary Freeview TV and is the perfect match for your HD (High Definition) TV. Available in 720p or 1080i, Freeview HD matches the best currently available from broadcast technology.

Frequency
Is it a high note or a low note? The former would live near the bottom of the frequency range, while the latter lives up top. A bass guitar produces mostly low frequencies while a flute or whistle produces high frequencies. Frequency is actually the pitch of a signal and is measured in Hertz (Hz).

Gracenote CDDB
A music recognition database based on the voluntary contribution of information from users. Most music software connects to CDDB to retrieve track names and band data for any given CD and some hardware – such as music servers – have the database built-in.

Hard Disk Drive (HDD)
An internal disc, such as those found in a computer, that stores large amounts of data. Typically such designs are capable of storing many gigabytes (GB) of data. Now a regular feature of MP3 players, DVD recorders and DVRs.

HDD (hard drive/disk) recorders
Components that offer an internal disk, like a computer, that can store large amounts of video and audio information. Not only found on DVD recorders, but also some Freeview and satellite boxes. They have a huge storage capacity (e.g. up to 4TB for hundreds of hours of programming). They also offer excellent editing tools so you can cut out ad breaks etc.

High Definition (HD)
At its most basic level, HD means better pictures. It is both a broadcast and a screen technology, and there are three types: 720p, 1080i and 1080p. Any screen implementing these standards is called ‘HD ready’. However, to aficionados, 1080p, which is sometimes called Full HD, is considered the only ‘true’ HD standard.

HD DVD
The second format (with the other being Blu-ray Disc) that sought to take over from DVD. Lost out in the battle against Blu-ray and was only ever used by a handful of companies, mainly Toshiba.

HDCP (High-bandwidth Digital Content Protection)
This system prevents unauthorised copying of data by ensuring that a digital data stream is not intercepted between source and display. Featuring in HD Ready screens, it means that you cannot make recordings of your high-definition programming, even if you have a high-definition recording device. The HDMI sockets on any HD Ready-badged TV must be fully HDCP-compliant.

HDMI (High Definition Multimedia Interface)
A wonderful 'pure' digital, high quality connection between a source and screen. It can carry both sound and vision between home cinema components. In its 1.3 guise it is able to carry high-def audio and greater colour spectrum. It is an important part of a High Definition system and has copy-protection capabilities.

HD Ready
A badge to denote screens that can accept and display High Definition pictures. To be HD ready, a TV must have a high-resolution screen - with a minimum of 720p pixel resolution - HDCP and either a DVI-I/D or HDMI socket. If a TV bears the HD Ready sticker, it is considered ready to accept and display a high-definition signal, whether from a HD DVD or Blu-ray player or from a digital broadcast.

Impedance
This is the load a speaker brings to bear on an amplifier or its electrical resistance. The higher the impedance – with 8ohms being top – the easier the speakers is to drive or power, meaning the speaker should work with lower power amplification, such as valve designs. If a speaker has consistently low impedance – say 4ohms – the speaker is much harder to drive.

Integrated
A design that comes in a single box or a component that's self-contained. As opposed to, say, a pre-amp and power amp combination that would come as two or three separate boxes.

LCD screens
Flat screen displays that use Liquid Crystal Displays to create the pictures. Commonly available in sizes from 14" - 60". Also known as TFTs (Thin Film Technology). LCD screens come in a wider range of sizes than say, plasma screens, and there is also a greater variety to choose from. They generally have a much brighter screen, pictures tend to look better under standard lighting conditions and they can often also double as a PC screen.

LED TV
LED TV is actually just a development of the conventional sleek LCD flat screens we all know and love. LED TVs are basically LCD TVs with one significant difference - they use Light Emitting Diodes (LED) to backlight the screen.

Line-level or line input
A component or analogue connection operating at 'line' voltage. If a device has a line input it typically means that it is capable of either amplifying or recording from an audio source. Dual phono (RCA) and 3.5mm headphone jacks are the most common form of connection.

Midrange
The middle of the frequency range, that sits between the bass and treble. The midrange handles most instruments and the human voice, so is of particular importance to musical replay. Many hi-fi components focus on accurate replay of the midrange at the expense of the rest of the frequency range.

Motion Processing - Refresh Rate
The standard refresh rate on TVs sold within the UK is 50Hz. This is the number of times a second the picture is "drawn". Higher quality TVs later increased this figure to 100Hz and then 200Hz. The higher the refresh rate the less flicker you'll notice and the picture should be more "solid" in appearance.

More recently, manufacturers have begun using their own measurement systems of motion processing and can't necessarily be compared between brands. Examples include LG - Motion Clarity Index (MCI), Samsung - Clear Motion rate (CMR), Philips - Perfect Motion Rate (PMR), Sony - Motionflow XR and Panasonic - Intelligent Frame Creation (IFC). All these figures are twice or more of the traditional 100Hz/200Hz refresh rate figures. Higher figures should equate to smoother motion but remember to stick to individual manufacturers if you want to compare like with like. Plasmas generally use a 600Hz sub-field refresh rate.

Moving coil, moving magnet
Types of phono cartridge. Remember, those things that sit in the groove of a record to pick up the sound. Sometimes called a stylus. Moving coil cartridges generally require a special phono stage and are the posher versions.

NTSC
The American system of TV broadcasting, this is not compatible with our PAL system. So, if you are buying DVDs from America, you will need to check that your DVD player/recorder is multi-region or has an NTSC-to-PAL converter.

Ohm
The measurement of electrical resistance, in hi-fi this is used to measure the impedance of a speaker.

Oversampling
A technique invented by audio boffins to improve the quality of audio replay. In essence it means generating more pieces of information – or bits - from a waveform that has already been recorded. Very clever.

PAL
PAL is the analogue broadcast system used in the UK, mainland Europe and 120 countries around the world.

Passive, Active
Active refers to a loudspeaker or subwoofer that includes some form of amplification, which is often digital in nature, to power the signal that is received from the crossover. The majority of loudspeakers are passive, which means they need some form of amplification to work.

PC Input
This means a computer can be plugged in. Simple really.

Phono (-stage, -input, -amplifier)
All things to do with a turntable refer to all things phono, and any phono-stage, -input, -amplifier is similarly describing such vinyl deliciousness. Phono cartridges work at very low voltages and require additional amplification before reaching the line-level parts of a pre/integrated amplifier.

Pixel
An individual dot of a TV picture’s image. The more pixels, the more detailed a picture is likely to be.

Pixel Resolution
Pixel resolution – horizontal times vertical. Generally, the greater the number of pixels, the more detailed the image.

Plasma
Flat screen displays that use heated phosphors to create the pictures. Screens most commonly come in sizes between 32" - 100" (smaller sizes are available, but most often than not they are prohibitively expensive to manufacture). Compared to LCD screens, plasmas offer better contrast, a wider viewing angle, cope well with fast-moving action and can display a wider range of the visible colour spectrum.

Power amplifier
Normally this refers to a separate component that forms part of a pre/power amplifier system. It will be the box with the meaty power section inside it. Such systems keep sensitive pre-amp circuitry away from such power amps as they emit lots of sonic nasties, although they deliver all the wonderful oomph. That said, a power amplifier can be found in any integrated amplifier as well, where they bung everything together in one box.

Pre-amplifier
Also sometimes known as a control amplifier, which gives a clue to its purpose. The term pre-amplifier commonly refers to a separate component that controls and routes signals coming from your source components. As with a power amp, all integrated amps have to have a pre-amp section to function properly.

Progressive Scan
A way of delivering a superior, flicker-free image. That's all you need to know for now. Seriously. You want more? Are you sure? Okay you asked for it. By drawing all the lines that make up a frame simultaneously, in one clean sweep - as opposed to drawing the odd lines and then the even ones, alternatively, in separate frames, as its the case with interlaced delivery - progressive scan offers a higher quality image with more depth and a more stable appearance. Ha!

PVR (personal video recorder)/DVR (digital video recorder)
Like the Sky+ box or Freeview equivalent, this piece of kit records video in a digital format to a hard disk. As well as set-top boxes, PVR technology is found in software, e.g. for personal computers, that enables video capture and playback to and from disk. Some manufacturers have started to offer televisions with DVR hardware and software built in to the television itself. Most PVRs offer a choice of recording modes, but the more capacity you want, the poorer the picture quality (as with the LP and EP modes on VHS tapes). All hard-disk recorders mean you can watch the start of a recording while the programme is still being recorded (also called ‘Chasing playback’). In essence, PVRs/DVRs are like HDD recorders, but with fewer features.

RDS
RDS, standing for the Radio Data System, arrived in the UK in the early 90s, adding a basic data and text service to FM radio, normally the station name. RDS also enables traffic reports to be automatically received by those listening to an RDS-enabled radio in their car.

Receiver
An amplifier that also comes with a tuner on board. It is very rare to see simple stereo receivers, although they are supposedly quite popular over the pond. More frequently, such a combination is found on a home cinema amplifier. In fact, the word receiver nowadays often simply refers to a surround sound amp – with a tuner.

Response Time
Time taken for screen to respond in milliseconds. A small figure means that there is a quicker response time, giving images a cleaner, clearer appearance with fast motion sequences.

SACD
Like DVD-Audio, this is another next generation audio technology, which promised extremely high quality replay, allied to potential surround sound mixes. And like its one-time competitor it hasn’t really caught on. In fact, it’s quite hard to find SACD players these days and when you do it is often on amazingly expensive machines that now only offer stereo replay. Weird, huh. That’s not to say it doesn’t work. Results can be spectacular, if you can find the software. SACD uses a very different technology from CD or DVD-Audio, implementing a one-bit delta-sigma modulation process known as Direct Stream Digital, with the very high sampling rate of 2.8224 MHz. This is 64 times the sampling rate used in making compact disc, hence the improved sound quality.

SCART
SCART used to be the most common standard for connecting audio-visual equipment together. With its 21-pin adaptor, SCART was a nice simple solution for carrying audio and visual signals. Previously, each of these would have had their own socket, requiring numerous separate connections and a spaghetti-type mass of leads. Somewhat usurped by HDMI now.

Sensitivity
This refers to how efficient a speaker and, accordingly, how easy a job the amplifier will have driving the speaker. Measured in decibels (dB) at one watt electrical input (W) from one metre distance (m), sensitivity ratings end up looking like this 90dB/W/m. But was this all number jumbo mean? Well if the figure is above 89dB/W/m, the loudspeakers will be a breeze to drive. If the figure is low – anything below 87dB/W/m – get yourself a monster amp as the speakers will need power aplenty to really sing.

SRS TruBass
An audio enhancement feature, TruBass enhances the perception of bass frequencies to provide deep, rich bass response from any size speaker.

S-Video
S-Video means separate video, which is a quality analogue video connections. It carries the video data as two separate signals (brightness and color). Many devices have both S-Video and component video inputs (along with the composite video input). S-Video does not carry audio on the same cable. 

THX
THX-certified gear conforms to the exacting standards laid out by Lucasfilm, unsurprisingly headed up by George Lucas, he of Star Wars fame. It is the trade name of a high-fidelity sound reproduction standard for cinemas, screening rooms, home cinema, computer speakers, gaming consoles, and car audio systems. These have recently been separated into various standards, the premium being THX Ultra 2. The THX system is not a recording technology, but mainly a quality-assurance system.THX-certification means that there is a high-quality, predictable playback environment that ensures that a film sounds as near as possible to the intentions of the mixing engineer.

THX Ultra2 & Ultra2 Plus
THX Ultra2 is a 7.1-speaker extension of the original Ultra spec. Ultra2 is designed to work well with multi-channel music and movie presentations playing up to reference levels in rooms of 3,000 cubic feet or larger. “Plus” adds volume control technology amongst other features.

THX Select2 & Select2 Plus
THX Select is a more affordable version of THX Certification. It is designed to play at reference levels in rooms of approximately 2,000 cubic feet. . “Plus” adds volume control technology amongst other features.

Transient
A fast, short signal such as a rim-shot that's a good test of a system's responsiveness.

TruSurround (serial Retrieval System)
Another sound technology, for audio and home cinema systems. For more information look at the site of SRS Labs Inc. at: http://www.srslabs.com

Tweeter
The thing found at the top of most loudspeakers! The tweeter is a drive unit that handles all the higher frequencies that need to be reproduced. Often shaped like a dome, more fancy variations include ribbon designs.

Twin tuners
Having two PVR tuners means you can record two programmes, or watch one and record the other.

Upscaling
All those extra new pixels on the latest HD screens are going to waste when replaying a conventional DVD. So the latest DVD players can upscale the original DVD signal produced, by filling in the gaps with new information, to produce better pictures. Upscaling isn’t quite HD DVD or Blu-ray – they cannot add detail that wasn’t in the original recording – but it does boost performance, thanks to the very complex algorithms used to create the new data.

Watts
A measurement of power. In hi-fi parlance it tells you how powerful your amplifier is or what power handling your speaker is capable of. Remember power doesn’t always equate to quality. So a powerful amp isn’t necessarily the best.

Wi-Fi
Wireless Fidelity is actually a certification of products to say they meet certain standards for transmitting data over wireless networks. A wireless network uses radio waves, just like mobile phones, televisions and radios. The radios used for Wi-Fi communication are very similar to the radios used for other devices. They can transmit and receive radio waves, and they can convert 1s and 0s into radio waves and convert the radio waves back into 1s and 0s. But Wi-Fi radios have a few notable differences from other radios. Most importantly, they transmit at frequencies of 2.4GHz. This frequency is considerably higher than the frequencies used for mobile phones and televisions. The higher frequency allows the signal to carry more data.

Woofer
The driver in a loudspeaker that looks after the lower frequencies. In most speakers – which are two-way designs – this is actually a mid/bass driver.