Jargon buster

There are so many different abbreviations and names for technology nowadays, we know it can get confusing trying to understand it all. If you can’t tell your UHD from your HDR (which no one would blame you for!) then you are in the right place. We break everything down into easy explanations for you below.


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Also known as 'True HD' or 'Full HD', 1080p offers a step up on standard HD and a huge improvement over SD (Standard Definition) TV. The most common place to find 1080p is from a TV broadcast or Blu-ray disc, although you need a 1080p (or 4K) screen to watch them in their full glory. 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 x 1080, or 2,073,600 pixels in total.


Less popular now but still available on many projectors, 3D essentially refers to content that is designed to provide a three-dimensional image, meaning a picture will "come out" of the screen and provide extra depth for a more realistic viewing experience. TVs and projectors generally decode this information in two ways; Active 3D and Passive 3D (see below), which require the user to wear glasses. There have been some glasses-free 3D sets, but they're few and far between, require you to sit in a very specific position and were very expensive.

3D - active

One of the two ways that projectors create a 3D picture. Active 3D uses a process known as Alternate Frame Sequencing. The TV or projector creates two images (one for the left eye, and one for the right) and flickers rapidly between the two. The glasses for this type of projector are usually battery-powered, have shutters that open, and close in time with the two images on the projector. Because this happens faster than the human eye can detect, the brain perceives a complete, three-dimensional image. The advantage of this format is a slightly sharper image. The main downside is the possibility of a slightly flickering image. For an alternative, see 3D - passive

3D - passive

Passive 3D uses the same glasses as the majority of cinemas, giving them an instant advantage over active sets as, if you've ever seen a 3D flick, you've probably got some specs lying around. They also produce a more comfortable, flicker-free image. The trade-off is that the image in 3D is lower resolution than the active system; however, many people do still prefer it. The only way to know for sure is to pop in-store and have a peek.


4K, or Ultra High Definition (UHD) followed 1080p Full high Definition (FHD), for even sharper images. 4K is so named because it has approximately 4000 pixels across (the exact number varies depending upon which camera the director chooses, but in the home you get 3840). The format gives approximately four times more detail overall than 1080p Full HD. 4K content is becoming more common too, with services such as Netflix and Amazon Prime offering movies and series on demand, plus over the air broadcasts and 4K Blu-ray.
Find out more here.

4K Blu-ray disc (UHD BD)

4K (also known as UHD) Blu-ray maximises the potential of your 4K HDR TV and offers a better picture than even UHD streaming. The resolution from films on UHD 4K Blu-ray now matches the 4K UHD resolution of your TV - maximising the potential of every pixel to give super-crisp detail and realism. With a wide range of UHD Blu-ray films already available, you can enjoy the ultimate in sound and vision.


8K UHD is the next stage on from 4K resolution and is currently the highest resolution available for commercial TV. It uses approximately 8000 pixels across (usually 7680) for four times the resolution of 4K UHD. Advantages for film makers using 8K cameras is there’s less need to be close-up to a subject for detailed images – useful for wildlife shots. Although 8K content is currently limited, online streaming companies YouTube and Netflix already have the ability to use the format – you will, however, need a very high-speed Internet connection. 8K TVs are starting to come on the market and offer 8K upscaling (see upscaling) as an initial improvement over standard 4K content.

AAC (Advanced Audio Coding)

A digital audio encoding system that compresses data files for greater storage capacity - think of the music tracks stored on an iPhone and you're on the right track. AAC (MPEG-4) is the next step-up from MP3 and offers superior quality and DRM support (Digital Rights Management, to prevent illegal distribution). AAC is the preferred coding system of Apple, so, for example, you'll find tracks on iTunes encoded this way. A typical file's size is 4MB for a 3-minute song, but this varies depending on quality and track length. This format is great for those looking to fit a lot of music on a smaller capacity device. It was initially designed to replace MP3 as the format of choice.

AI (Artificial Intelligence)

AI is usually combined with voice control and smart home tech (see below) for smart control and learning functionality. LG’s artificial intelligence system, ThinQ, brings together a wide range of products under intuitive control. For your TV this means intelligent voice control and the ability to seamlessly work with third party services from Google and Amazon. The more LG ThinQ AI products you have around the home the more seamless and integrated the control becomes.


AirPlay is the Apple technology that enables you to stream music, videos or photos from a compatible device to a speaker or screen. Any device running iOS (such as an iPod Touch, iPad or iPhone), or computers with iTunes installed can send content. To find compatible amplifiers, speakers, or anything else in between, look for the AirPlay logo.

AirPlay 2

AirPlay 2 is the latest version of Apple’s wireless system and offers a number of advantages. AirPlay 2 is now powerful for seamless streaming of larger files. AirPlay 2 is also optimised for multi-room systems, letting you enjoy wireless music and podcasts throughout your home. Better still, more manufacturers than ever have made their products compatible so you’ll get the benefit from a huge range of brands, including Sonos, B&O, Bose, Bluesound, Naim, Polk and many others.


A stereo amplifier (AKA Integrated amp) is the driving force behind your sound. It is the device that takes an audio signal, boosts the level (volume), controls the bass and treble and throws it out to the speakers in order to power them. Also see Pre-amplifier and Power amplifier.

Amplifier - integrated

The design of any audio amplifier is made up of two main sections, the pre-amplifier and the power amplifier. The 'pre' takes care of choosing your source, setting the volume and any other adjustments such as bass and treble controls. The 'power' is the bit that powers the speakers! High-end set-ups commonly use separate pre and power amp units, but most of the time both bits are in one box. This is known as an integrated amplifier.

Amplifier - power

A power amplifier is perhaps the simplest piece of hi-fi equipment. It's the one that makes audio loud! They most commonly have two inputs and two outputs; one for the left channel and one for the right. The sound comes in from the preamp via an interconnect cable (either phono or XLR) and goes out via speaker cable. The advantage of breaking this part of an amplifier design out into a separate box is that the high current amplification circuitry can generate interference that has a negative effect on other signals in an integrated design.

Amplifier - pre

The pre-amplifier is the bit that you interact with, choosing the source and setting the volume, as well as any bass and treble adjustments. Unlike a regular integrated amplifier, it can't connect directly to speakers; you'll need a power amp to boost the signal to the right level first. You also get pre-amplifiers designed for home cinema use, though these are normally referred to as processors. Some high-end equipment, such as music network streamers, have pre-amplifiers built-in, for use with power amplifiers or active speakers (See amplifier - power & passive / active (speakers).


The original meaning of the word 'analogue' is replication. In hi-fi terms, we often use the word to describe the opposite of 'digital'. An analogue version takes the original material, be it sound or picture, and replicates it in a quantifiable, viable format. One example of this is vinyl, where the sound waves of the music are represented in the physical variations of the records' grooves. Another example is in traditional film, where each frame is captured as a physical photograph on a film reel. The projector flashes on each photo, projecting a “motion picture” on the screen. Other examples include radio waves or a physical video or audio cassette.


AptX is an Audio codec for storing and sending compressed information wirelessly between devices. It's most commonly used for Bluetooth-ing music to a compatible speaker or dock. It provides the best bandwidth for sending media to a compatible receiver, meaning when you stream music from your phone, tablet, laptop or any other compatible device, you can enjoy the best possible sound quality and all wire-free!


High Definition Bluetooth wireless audio. The enhanced version of aptX by Qualcomm delivers ‘better than CD’ sound quality from wireless transmission. It support up to 24 bit/48kHz file transfer for true HD sound quality. Just remember, both transmitting and receiving devices need to be compatible with the aptX HD format for the full effect.

AptX Low Latency

AptX Low Latency delivers sound that’s in sync with what you see on the screen. Crucial for gaming, Low Latency AptX keeps you totally locked in to the action. The 40ms latency always improves lip sync issues – making it ideal for dialogue from TV and movies, too.

Aspect ratio

The displayed width of an image divided by its height. Chances are, at some point, you've noticed black bars along either the sides or the top and bottom of your TV screen. This is because whatever you're watching has been made in a different aspect ratio to the screen. Nearly all TV shows since the mid-2000s have been made in the 16:9 'widescreen' format that's the same shape as your TV. Since the advent of colour film, many movies were made in this shape too. However, older TV shows and movies are in the square-ish '4:3' aspect ratio. Most movies use a much wider image for a more epic appearance, which you may hear referred to as 21:9 or 2.23:1 (the screen is 2.35 times wider than it is taller). To fit these different ratios onto your 16:9 TV or projector you can stretch them, (which can distort the image), zoom in, (which cuts off the edges), or display black bars on the top or bottom - or sides when watching 4:3 content. The majority of TVs let you choose which you prefer from these options.

AV Receiver (Also known as a Home Cinema Amplifier)

Think of this as the heart of your surround-sound system. The term "receiver" refers to the fact that it has a built-in radio tuner - but it's much more than that! Capable of receiving signals from a variety of sources such as Blu-ray players or over-the-air TV boxes, the receiver decodes the surround sound information and amplifies the speakers. They can also pass the video signal on to the television. This means they can act as a complete switching hub for your audio and visual entertainment. Most support high-end audio formats such as Dolby Atmos and DTS:X. You can also connect audio sources, such as CD players and turntables (with phonostage), and many now offer wireless music streaming to cover all your home entertainment needs.


It's the rhythm in your reggae. It's the boom in your Bond film. This is the lowest part of the frequency range, which is reproduced by woofers and subwoofers in loudspeakers. The rumbling often heard in home cinema is a classic example of extreme bass.


Bi-wired crossovers in speakers process treble and bass signals individually. This reduces the chance of bass "leaking" across to the treble track, which can cause mild distortion. Bi-wiring may or may not improve the sound, depending upon how well the crossover is engineered in the first place. Bi-amping uses two amplifiers - one for the bass and the other for the treble signal. This produces a significant improvement in sound quality.

Bit rate / bit depth

Bit rate is effectively a measure of quality of a digitised audio or visual signal. Measured in Kbps or Mbps (Kilo-bits per second or Mega-bits per second; a Mega-bit is 1024 Kilo-bits), it's telling you how much data is used every second. A higher number means better fidelity, as the digital description of the sound or picture is more detailed. This does come at the expense of a larger file size however. When people talk about 'bit depth' (e.g. 24bit audio or 10bit colour) this refers to the range of data that can be described by the file. 24bit audio, for example, is able to produce more subtle changes in volume than the 16bit standard found on CDs, and higher bit colour can show a greater range of shades between primary colours.

Blu-ray disc (BD)

They look like DVDs, but they're a whole lot better. Not only do they offer amazing quality high definition picture, but you'll also enjoy better sound quality than DVDs or HD movies streamed from the web. Another advantage over downloads is access to special features, which can include information appearing over the top of the movie image: pretty cool for film buffs! New releases tend to cost only a pound or two more than DVDs and all Blu-ray players will play your existing DVD collection too. A no-brainer for film and TV fans. See also, 4K Blu-ray for the higher resolution version.


Named after the ancient Nordic king Harald "Bluetooth" Gormsson… (Would we lie to you?), this wireless media standard facilitates the transfer of data between compatible devices. Most commonly, it is used in smartphones or tablets to stream music through a speaker system of some kind. The capability is built into a huge range of audio devices from hi-fi systems and soundbars to headphones. There is also a range of discreet units available to add-on to existing systems.


When referring to a TV or projector, 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 (candela per square meter), while for projectors it is measured in ANSI (American National Standards Institute) lumens. In both instances the brighter the image, 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 or projector cannot deliver a bright image, you'll need to be able to control the light in your room, and this isn't always possible.


This handy bit of technological hocus-pocus lets you send content between compatible devices, without the need for cables. Miracast can support 1080p video with 5.1 surround sound, meaning its most common use is to stream content from a phone or tablet to a television. It also works from Wi-Fi direct, meaning the signal travels directly between devices rather than having to go through a wireless router. Google Cast is another popular option for picture, while music streaming services such as Spotify use a version of 'casting' to playback on compatible hi-fis/speakers.


When saved as raw data, audio files take up a lot of space and video an astronomical amount. The cameras used to film The Hobbit, for example, use up to 5GB a minute! Therefore, the files need to be squeezed down, or compressed, somehow. A codec is a key to compressing a file so that it's a lot easier to manage. Each codec, however, is like a different language, and whatever's playing it back needs to speak the language too. This isn't as much of a problem as it used to be; Smart TVs, Blu-ray players and other components tend to be compatible with lots of different codecs. That said, if you are interested in playing back videos from a USB drive or similar, it's worth checking compatibility. The same applies to music files. Remember – the codec is the language the compression uses, as opposed to the file type, which is the vessel for all of the information.


The greater the amount of colours a screen can produce, the more natural the image will be. LED backlit and traditional LCD screen shine a blue light through a yellow phosphor film to create white light. This light is then shone through red, green and blue filters (sub pixels) to create the full colour range. Quantum dot LED TVs create brighter colours and therefore a larger, more dynamic range. OLED technology can produce the widest range of colours (See quantum dot and OLED for more information).


The highest quality analogue video connection available. It's been completely overtaken by HDMI, with many units now offering no alternative to this ubiquitous connection. However, if you have a particularly good older DVD player, or a games console like the Nintendo Wii or Sony PlayStation 2, it's still worth hunting down a component cable and using this input on your TV.

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 spec for any display; being able to display a deep black alongside a bright white is what makes images appear punchy. However, due to various methods of measurements, remarkably different measured values can sometimes produce similar results. Some manufacturers no longer list contrast ratios, as claimed figures were becoming almost comically high. In typical viewing situations, the contrast ratio is significantly lower than these claims, making it harder to distinguish between different devices with very high contrast ratios. OLED TVs produce infinite contrast due to their absolute pure blacks. The best solution is to visit our stores and compare with your own eyes.


The part of a loudspeaker that splits the incoming audio signal into separate frequency ranges, and then sends these signals to specific drivers, such as, in a two-way design, the tweeter or woofer. A three-way crossover splits the signal three ways, to three or more drive units. They have a huge influence over the final sound of a loudspeaker design. The better the crossover, the less the sound will distort at certain frequencies.


Digital Audio Broadcasting. Digital radio transmission gives a greater selection of radio stations, and wonderful ease of access. What's more it allows the broadcast of information like the title of the current track or programme. Some products are compatible with DAB+ which offers higher quality audio. This system isn't yet used in the UK, but you'd be covered if we did ever change. One advantage of DAB radio is its ease of use tuning in - no more white noise between stations. An alternative is Internet radio, which offers many of the same benefits as DAB.


Standalone DACs (digital-to-analogue converters) squeeze the maximum sound quality from digital music (including CDs, streamed tracks and more). Digital files played through a decent DAC will achieve significantly superior levels of detail compared to the cheap DAC chips built into most digital kit. In essence, a DAC takes the digital stream of 1's and 0's and converts them into an analogue waveform. This waveform is analogous of the original sound, so the better the DAC, the more accurate the sound produced. A good DAC should be heard in comparison to poorer DACs for the most obvious demonstration of quality. Why not pop in for a demo and hear the difference for yourself?


This can refer to storage (data) or signals. The word 'digital' comes from the Latin 'digitus' (meaning 'fingers', as in 'digits for counting'). Digital data is a discrete (individual) discontinuous (has a precise beginning and end container) representation of information. For example, this can be an mp3 file on your phone, or movie files on a Blu-ray disc. A digital signal, on the other hand, is the transfer of information. This can be bitstream (a continuous signal of binary 1's and 0's), or a more complex waveform (see bit rate and bit depth for more information).


How big is yours? Where possible, we try to include dimensions of a component both including and excluding any stand, bracket or feet it may come with. For accuracy, we always use millimetres in our measurements. Make sure to check you can fit your chosen items in the space you have in mind for them!


DivX is a brand name for products created by DivX Inc., which have become popular due to their ability to compress lengthy videos into small sizes, while maintaining decent video quality. It is commonly associated with burning or ripping video content onto a hard disk. As HD has become more popular, DivX has become less common, but it's still compatible with a wide range of devices.


Established by Sony in 2003, DLNA (Digital Living Network Alliance) is an organisation that promotes the seamless connection of digital devices through your home network – Ethernet or wi-fi. Popular uses include streaming music and movies files from PC or laptop to hi-fi system or TV.


Over the years, few companies have been quite as important for cinema as Dolby. From the origins of surround sound, through to completely immersive cinema, Dolby have brought many cutting-edge formats to the home.

Dolby Atmos

The next dimension in surround sound - Dolby Atmos creates an immersive experience like never before. Extra speakers fire sound from above or 'bounce' sound from the ceiling, using an innovative design. Many modern AV receivers can easily be upgraded with the addition of Atmos speakers. Far more realistic surround effects are created using advanced 'object based' sound mixing techniques. Click HERE for more information in our useful in-depth guide to Dolby Atmos.

Dolby Atmos Height Virtualization

It's not always possible to accommodate Atmos height speakers, which is when Dolby Atmos Height Virtualization comes in handy. Play any Dolby format and enjoy a more immersive sound with virtual height enhancement – using your existing speakers.

Dolby Digital

This is the technology that puts the ‘cinema’ in ‘home cinema’. Pick up almost any DVD or Blu-ray title and you will find this almost-ubiqutous surround sound format as an option. Typically 5.1, sound is mastered in a multi-channel format to give an immersive surround sound experience. You can also find Dolby Digital on many movie streaming services too.


Dolby Digital EX

Dolby Digital EX takes the Dolby Digital 5.1-channel setup one-step further with an additional surround channel (reproduced through one or two speakers) for extra dimensional detail and an enveloping surround sound effect. It was used on very few DVDs and has now been superseded on Blu-ray by the 7.1 capabilities of Dolby TrueHD.

Dolby Pro Logic

Dolby Pro Logic was the foundation for multi-channel home cinema. Originally, it was a way of fitting the signal for a rear speaker into standard stereo sound. While that function still works perfectly, its most common use today is making use of all the speakers in your set-up even when what you're watching is not in surround.

Dolby Pro Logic II, Dolby Pro Logic IIx and Dolby Pro Logic IIz

Version two of Pro Logic has had a number of incarnations over the years, with the first being Pro Logic II. It turns a properly encoded two-channel source into a full-blown 5-channel signal. Other improvements 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 a lossless audio format (see lossless) commonly found on Blu-ray discs. This gives equivalent quality to what the engineers would have heard when mixing the soundtrack in the studio, at a sample rate of up to 192 kHz, as opposed to the 48 kHz maximum of regular Dolby Digital (see sample rate). This format isn't possible on a DVD as there simply isn't enough room on the disc. For those who've invested in an extra pair of rear speakers, it also supports discrete 7.1. There was a time when only a handful of Blu-ray players and AV receivers were compatible, but it's now reached near ubiquity. That said, it's still worth double-checking if you're interested in getting this massive upgrade.

Dolby Vision

Dolby Vision is an advanced form of HDR (see ‘HDR’) for enhanced image quality. Dolby Vision adds metadata to a standard HDR signal, giving scene-by-scene, adaptive image enhancement. Dolby Vision is also backwards compatible with HDR10 although you will need a Dolby Vision compatible TV and source for the system to operate correctly.

Dolby Vision IQ

Dolby Vision IQ takes Dolby Vision to the next level, making it the ultimate HDR-type picture processor. Just like standard Dolby Vision, the IQ version uses metadata within the signal to adjust the picture quality for the best contrast. Where IQ goes further is in using light sensors inside the TV to improve the picture’s brightness, without ‘washing out’ the depth. This means you get a consistent picture quality, however light or dark your room is. Whether you’re watching a brightly lit sports event or moody movie, Dolby Vision IQ adjusts to suit.


A driver is a specific word that describes the individual cones within a speaker. For example, a two-way speaker features two (or more) drivers, one for the high frequencies (known as a tweeter) and one (or more) for the mid-range and low frequencies (known as a woofer or mid/bass driver). There are different types of driver, but ultimately they all vibrate to create sound waves.



DTS, Inc. started its work on a surround sound format nearly four years after Dolby Laboratories, yet managed to bag some quite notable backers. Not least of these was Steven Spielberg, who needed a breakthrough format for his 1993 production Jurassic Park. It was also the first home release to feature DTS. Since then DTS has released many formats, both 'cinema' and 'home', to improve the movie experience.



This uses either a traditional 5.1 soundtrack and converts it to 6.1 (with an additional surround speaker), or DTS-ES Discrete 6.1, which has all 7 audio tracks mastered and recorded to the soundtrack, for a more realistic surround sound. The latter of which was seen as an improvement over Dolby's Digital EX, which did not feature a discrete 7th channel.


DTS-HD High Resolution / DTS-HD Master Audio

DTS' two high definition audio formats. 'High Resolution' was the first of the two, offering 96kHz sampling rate (see sample rate) and 24 bit depth resolution (see bit rate / bit depth). 'Master Audio' has subsequently replaced 'High Resolution' as it contains up to 192kHz/24bit audio.


DTS Neo:6 / DTS Neo:X

These processing standards take a 5.1 mix and convert it to either 7.1 (Neo:6) or up to 11.1 (Neo:X). The 11.1 set-up utilises a centre speaker, a left-right stereo pair, two front-wide, two front-height, two rear-side, two rear speakers and a single subwoofer.


DTS Surround

The original surround sound format, DTS Surround offers a fully discrete 5.1 set-up. This uses a centre, a left and right stereo pair and two rear speakers. It also includes a subwoofer track for the LFE (low frequency effects).



An 'object-based' audio codec (see Dolby Atmos). The advantage of this format is the processor (or home cinema amplifier) can complete 'on-the-fly' calculations based on the speaker configuration of the room, giving you demonstration room quality home audio, regardless of your room size or layout.


DTS Neural:X

Ever wanted the DTS:X benefits from a non-DTS encoded signal? Then this one is for you. DTS Neural:X upmixer supports Dolby formats, giving you DTS surround whatever the format.


DTS Virtual:X

DTS Virtual:X also creates a more enveloping sound from any DTS codec. Compatible with 2, 5.1 or 7.1 speaker configurations, DTS Virtual:X gives the impression of height and immersive sound.



DVD-Audio is a high-quality format, which uses a DVD's superior storage capacity to offer sonic improvements over conventional CDs. 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, with some releases fetching collector's prices. These days, Pure Audio on Blu-ray tends to be the high-resolution audio physical disc of choice.



DVI (digital visual interface) is a video connection with a large rectangular connector that was commonly used by HDTVs and Projectors but was quickly phased out as HDMI gained popularity. Unlike HDMI, DVI only carries picture information, no sound or other data. If you're buying all new equipment you needn't worry, but DVI to HDMI cables are readily available should you find yourself in need of one.


Dynamics (audio)

The dynamics of a system refers to its reproduction of the quietest and loudest parts of a piece of music. The difference between these is referred to as 'dynamic range'. A highly dynamic system is desirable as it will be able to go from extremely quiet to extremely loud as swiftly and easily as an F1 driver going around a racing track, and also express far more subtle changes in volume. You may come across people complaining about a recording having poor dynamic range, saying that it is "overly compressed". This basically means that, even if you have a very dynamic system, the recording makes it sound otherwise. It's perhaps best not to bring up this issue with any audiophile friends unless you're prepared for a lengthy rant!



Standard ARC (Audio Return Channel) lets you use a single HDMI to route the video source to your TV while simultaneously routing the sound from its tuner or smart TV back to the audio amp or soundbar. In essence, it cuts down on cable clutter. eARC (enhanced Audio Return Channel) goes one stage further by boosting the bandwidth and speed. This makes it compatible with data-hungry formats, such as Dolby Atmos and DTS:X.


EPG (Electronic Programme Guides)

With Digital TV now ubiquitous, everyone has access to an EPG, though you may not know that's what it's called! It's the technical term for the TV guide you can bring up on-screen to look through what's on across all channels. Some internet-connected services such as YouView and Freeview Play enable you to access programs from catch-up services, all from the one EPG.



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File format

Unlike a codec, a file format is usually instantly obvious (see codec for more information). On most operating systems, such as OSX and Windows, the file type is determined by the last letters after the dot in the file name. When you are looking to playback video or audio files on a system, be aware it must support both the file type and codec. For example, an AVI movie file could have any codec from a large list, including DivX and XVid (among others).



Freesat is the subscription-free satellite TV service that gives you a whole host of benefits. The service uses the same satellite as Sky Digital, so if you are switching over you will not need to reposition your dish. The advantage of Freesat TV is that it offers great reception no matter where you are. Unlike TV over-the-air (see digital tuners), the only thing that will limit your reception are trees, large buildings or other structures that can obscure your line-of-site to the satellite. This makes it ideal for those with reception issues in aerial black spots.

A Freesat tuner can either be in-built on a TV or accessed via a separate set-top box. For recording, look out for the Freesat+ logo - this provides storage space with capacity to record, pause and rewind live TV. Once tuned in, you will be treated to a wide range of both standard and HD channels, including great entertainment, news and children's entertainment. Many Freesat devices also offer catch up TV, as well as smartphone and tablet apps to control what you are watching, such as Freesat Freetime.



If you've got an aerial for watching TV, Freeview is what you'll pick up. As well as offering a wide selection of subscription-free TV and radio channels, there are also some that you can unlock with a subscription, without needing a new box. For those with a satellite dish, Freesat is your option if you want to avoid monthly costs.


Freeview HD

As well as offering over 70 channels, Freeview also offers, at time of writing, up to 15 channels in incredible HD quality, still completely subscription-free. If you want to receive these you'll need to check that the TV or recorder you're buying is Freeview HD compatible, though the vast majority now are.


Freeview Play

Freeview Play is a Smart TV service by the people who originally brought digital TV to the UK. It offers the same channels as Freeview HD, but with added catch-up services. Like all Smart platforms it does require a good internet connection, however it receives its live TV signal through a standard TV aerial. An advantage of Freeview Play over other systems built into certain manufacturers Smart TVs is the fact both catch-up and live TV features on the same guide.


Frequency range (audio)

Like any other wave, sound waves have a frequency or how many times they repeat every second, measured in Hertz (Hz). The human ear can hear sounds from, depending upon the individual, 20Hz to 20,000Hz (20 kHz). Low sounds, or bass, come in at the bottom and high sounds (treble) live at the top, with the space between referred to as the mid-range. Electronics, speakers and headphones usually list a frequency range in their specification, which gives you some indication as to the performance, though a demo will tell you much more about how they sound (see running in (speakers) for more information on getting the full frequency range from your speakers).


Gracenote CDDB

Ever put a CD into a computer and wondered how it knew what album it was and the track titles? The answer is most likely the Gracenote CDDB (CD Database), a massive online archive that's constantly updated by users. As well as being used by music software like iTunes, it's also built-in to most music servers.


Hard Disk Drive (HDD)

Internal storage, such as that found in your computer, that holds large amounts of data. They're also commonly found inside recorders and music servers. As a rough guide, an hour of recorded video takes up around 2GB in standard definition or 4GB in high definition. For music, each 1GB is enough for about 20 albums in MP3 quality or 4 at CD-equivalent lossless quality. Mobile phones and tablets can often access the data, such as music and video files, on them quicker as they use solid-state drives (SSD), which have a quicker access time.


Hard disk drive recorders

A component that can record to its own internal space without requiring discs or tapes so you don't have to hunt for free space on a disc whenever you want to record something. You get other advantages too, like being able to easily edit out ad breaks, for example. One popular specific type of HDD recorder for recording TV broadcasts is the personal video recorder (see PVR for more information).


HDCP (High-bandwidth Digital Content Protection)

This system is designed to prevent unauthorised copying of data. In the early days of HD, some legitimate equipment wasn't compatible and caused issues, but this is no longer an issue. Put simply, as long as you're not trying to breach copyright, you won't have any problems. HDCP 2.2 is the standard equipment needs to support to be able to playback 4K Ultra HD content, be it Ultra HD Blu-ray players, 4K TVs or set top boxes.


HDMI (High Definition Multimedia Interface)

The digital successor to SCART, a single HDMI cable can carry high definition pictures, surround sound audio and remote control info between two devices. Nearly any video source you buy now has an HDMI output, from TV set-top boxes to games consoles to Blu-ray players and even laptops and cameras. Home cinema amplifiers also have multiple HDMI ports to act as a video switcher for your TV or projector.


HDMI 2.0

HDMI 2.0 is an enhanced version of HDMI using the same connections but offering many technical advantages. These include the ability to handle 50/60 frames per second from 4K signals, 48-bit/pixel colour, 32 channel surround sound, full 21:9 aspect support plus much more.


HDMI 2.1

HDMI 2.1 builds on the 2.0 version. It supports higher resolution and refresh rates, making it the default standard for 8K TVs and sources. HDMI supports Ultra High Speed HDMI cables, cable of carrying the full 48 Gbit/s bandwidth required by 8K and even up to 10K resolution. HDMI 2.1 also supports Enhanced Audio Channel (see eARC).


HD Ready

A badge to denote screens that can accept and display 720p/1080i High Definition pictures. Over time, this term has come to mean a TV with a lower resolution than 1080p, (which is often referred to as 'Full HD'). Common on smaller screens and some budget models, you'll still see a big improvement in high definition from standard definition pictures with these screens, though you won't see every last detail from sources such as Blu-ray (1080p) discs, or Ultra HD 4K.



HDR stands for High Dynamic Range and, in this instance, greatly enhances a TV’s picture quality. HDR offers brighter whites and darker blacks for more dynamic image quality. You’ll also notice more detail within the darkest and lightest areas of the image – such as the texture on the inside of a cave wall. This feature also makes HDR hugely popular with gaming fans, as you can seek out foes lurking in the darkest areas of the game!



HDR10 is the next generation of HDR. HDR10 is widely supported by movie producers and features on Sony’s PlayStation, Xbox One and Apple TV platforms, making it more widely available than the rival Dolby Vision (see Dolby Vision above). It uses wide-gamut Rec. 2020 and a bit depth of 10-bits for rich, life-like colour.



Also known as HDR10 Plus, HDR10+ was announced by Samsung and Amazon Video and improves upon HDR10 by adding dynamic metadata to adjust brightness on a scene-by-scene or frame-by-frame basis. Controlling the colour more accurately creates a more natural image that’s brighter only when it needs to be. This means it’s much closer to the similar Dolby Vision system. As with Dolby Vision, however, not all TVs and sources are compatible, so you’ll need to check this.


Headphone Amplifier

These are the best way to enjoy the best possible sound from your favourite set of headphones. Dedicated headphone amplifiers are specifically designed to provide maximum power output with minimum distortion. Much like stereo integrated amplifiers, headphone amplifiers come with a variety of features and specifications. Higher current outputs drive high-end headphones that require more power, and hand-held versions have built-in batteries for ideal portability. Some versions also come supplied with built-in DACs [Digital to Analogue Converter], to extract every last detail of sound from digital sources.


High definition (HD - video)

At its most basic level, HD (high definition) means better quality pictures. It is both a broadcast technology and a screen resolution, and there are several signal types including 720p and 1080i. Any screen implementing these standards is called 'HD ready'. The next level up, 1080p, is sometimes called Full HD. Above this resolution is Ultra HD (4K), which gives resolutions four times higher than 1080p.


High resolution audio (Hi-Res)

High Resolution Audio provides exceptional sound quality from High Resolution music files. Typically these are DSD, WAV, AIFF, FLAC or ALAC files at 24 bit/96kHz, 24 bit/192kHz or higher rates. Think of it like High Definition TV for your audio and the difference is easy to hear.


Home Cinema

Home cinema has come to be a catch-all term for a system that plays music and movies with a TV or projector and an external speaker system of some kind, usually surround sound. The whole idea is to recreate as accurately as possible the picture and sound quality of a cinema auditorium. Filmmakers want their work to be showcased in all its glory, with not a line of dialogue missed or a pixel out of place and a home cinema is just the tool for the job - in fact, you'd be surprised at how easy it is to build a seriously impressive system.


IMAX Enhanced

A collaboration between IMAX, DTS and award-winning Hollywood sound mixers, IMAX Enhanced certification delivers stunning levels of sound quality. Only the highest quality home cinema equipment meets the standard. IMAX enhanced content is found on certified HDR streaming and UHD Blu-ray and promises to offer the next step-up in sound from the already impressive DTS:X.


Impedance (speakers)

This is the load a speaker brings to bear on an amplifier or its electrical resistance, measured in ohms. The higher the impedance - with 8 ohms being the norm - the easier the speaker is to drive or power, meaning the speaker should still work well with less power. If a speaker has consistently low impedance - say 4 ohms - the speaker is much harder to drive. It's important to make sure your speaker's impedance is above the minimum specified by your amplifier. If you connect two pairs of speakers in parallel the impedance halves, meaning that two sets of 8 ohm speakers present a 4 ohm load to your amp.


Internet Radio

In its truest form, this is simply a device that allows you to stream radio stations through the Internet by connecting to your home network. Because the device is connected directly to the web, it doesn't rely on localised radio signals to pick up stations - instead you get access to thousands of radio stations from all over the world. Also, because an Internet connection has better bandwidth, sound quality and signal reliability tend to be better than digital radio (subject to the codec and bit rate used by the station).


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Laser projector

Laser projectors are a type of Solid State Light (SSL) projector and do away with conventional light sources (bulb) altogether. This is replaced by laser diodes. The main advantage this brings is longer life, but there are also import advantages in the quality of light over time. While bulb-based projectors gradually deteriorate over time, laser diode ones stay every bit as crisp as when they were new.


LCD projector

One of the oldest, and generally the cheapest form of digital projector; creates an image by breaking a beam of light into its 3 primary hues before shining each one through a tiny LCD screen that displays the picture. The 3 hues are then recombined inside a prism before being beamed onto your screen.


LCoS Projector

LCoS stands for Liquid Crystal over Silicone. The light from the lamp is split into red, green and blue. The colours are then shone onto micro-devices, which contain liquid crystals atop a reflective surface. When an electric charge is administered, the liquid crystals alter their shape, and act like filters that control how much light hits the reflective surface according to desired brightness or contrast. The complete image is then recombined and projected onto the screen.


LED projector

LED projectors usually work alongside DLP technology but use an LED lamp rather than conventional bulb. This has the advantage of longer life and also a more consistent quality of light over time.



LED TVs use essentially the same screen technology as LCD TV but with LED backlights, rather than fluorescent bulbs. This not only makes them more efficient and cheaper to run but also slimmer in depth and better able to dim local areas of the screen (see Local Dimming and Full Array Dimming below). Superior quality lighting means a brighter, purer picture with enhanced contrast.


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. A pair of white and red RCA plugs or a 3.5mm mini jack is the most common form of connection. Note that the output from a turntable is usually a lot lower than line-level and requires a phono pre-amp (see Phono pre-amp) – also known as a phonostage.


Local Dimming and Full Array dimming (TV)

Local dimming is a term used to describe the backlight on LCD/LED TVs. Local Dimming is superior to standard backlighting as it dims individual areas on the TV screen to enhance brightness and contrast. Full Array dimming is the next step up and uses even more individual zones of light control to get even closer to OLED (which dims each pixel individually).



Lossless compression ensures perfect recreation of stored data in smaller-than-original file sizes. For all you audiophiles out there, it means you get to rip your favourite tracks to your computer without it chopping bits out of them to preserve storage space. When these files (often known as FLAC or Apple Lossless files) are played back, they retain every bit of their original detail - music to our ears. This is used in Hi-Res music (see High resolution audio) due to the relatively small file size, while maintaining quality.


Midrange (audio)

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. As most humans are most aware of the frequency of midrange that vocals use, 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 - TruMotion (TM), Samsung – Picture Quality Index (PQI), Philips – Picture Performance Index (PPI), Sony - Motionflow XR and Panasonic – Back Light Motion Rate (BMR). 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. The best way to compare the motion of TVs is to demonstrate scrolling text. The better the screen, the smoother the image will be.


Moving coil, moving magnet

Types of phono cartridge for your turntable. Moving Coil cartridges generally require a special phono stage and are found in high-end systems. Moving Coil cartridges generally have a flatter, more accurate response, but do not have replaceable styli, unlike the more cost effective Moving Magnet option. Whichever type of cartridge you use, it’s important to match to the correct type of phono pre-amp (MM or MC).


Multi-region (DVD)

If you want to play DVD’s from America, or most places outside Europe for that matter, you’ll need a multi-region DVD player. Discs are encoded in 6 different regions (with the UK falling into region 2). A standard DVD player will only play region 2 discs.


NAS drive

An external hard drive with a twist! NAS stands for "Network Attached Storage" meaning that once you plug your NAS drive into your wireless router, you can fill it with music, movies, even photos and important documents. All of these can then be easily accessed by any other devices operating on the same internet connection - so you can back up all your favourite media, and still get your hands on it without even switching on your computer - ideal for anyone with a wireless streaming system (see Network streamer).


Network streamer

One of the newer additions to the world of hi-fi separates, a network streamer piggybacks onto your router in order to give you access to a variety of Smart services. For example, should you have any music stored on your home PC or on a NAS drive; the network streamer can discover it and play it through your hi-fi, all at the touch of a button. Depending on the model, you may also get direct access to streaming services like Spotify and Tidal that, with a subscription, will give you unlimited access to a library of music that you can listen to whenever you like. Add an internet radio service into all that and you've got a massive mine of musical multiplicity!


NFC - Near Field Communication

NFC (near field communication) allows close proximity connection simply by holding your tablet or smartphone next to the device. Once paired you can either stream music (Bluetooth enabled speaker), or send files (to other smartphones / tablets etc.)



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



OLED (Organic Light-Emitting Diode) is an advanced form of TV technology that’s used in some of the finest TVs on sale. Unlike LED, which uses backlights shone through groups of pixels, each OLED pixel is individually illuminated. This gives OLED TVs stunning levels of contrast as a bright white pixel can be directly next to a pitch-black one – something almost impossible to achieve with LCD/LED TVs. This means black levels are far better than LED TVs and ‘inky’ deep.


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PAL was the analogue broadcast system used in the UK, mainland Europe and 120 countries around the world, which runs at 50Hz. NTSC was used by the rest of the world, including North America and Japan; this runs at 60Hz. While these different frame rates are still used, the arrival of digital TV means these terms are now of little relevance as any HD Ready or better TV can accept both 50Hz and 60Hz signals.


Passive / active (speakers)

In a hi-fi context, active means that a unit has a built-in amplifier, whereas the passive equivalent would require separate amplification. The most common example is an active subwoofer as they benefit from amplification specialised to bass, though you can also buy pairs of active speakers.


PC Input/VGA

For older PC's that don't have an HDMI or DVI output socket, look for a TV or projector with a 'PC Input', otherwise known as 'VGA'. Although far fewer TVs feature this older style of input these days, it's still available - usually on budget models.


Phono pre-amp / phono-stage

The signal from a turntable is much weaker than line level (see above) and therefore requires additional amplification. A phono pre-amp can either be built into your turntable or amplifier. If neither is equipped, you'll need to purchase a separate device. If you use an MC (Moving Coil) cartridge, do ensure that the phono pre-amp is compatible (MM, or Moving Magnet, is standard).



An individual dot of a digital image or a TV screen. The number of pixels an image or screen is made up of is known as its resolution, expressed as the number of pixels across by the number high (horizontal times vertical). So, for example, a 1080p image is 1920 pixels across by 1080 high. Generally, the higher the resolution, the better quality an image is likely to be, but both your TV and your signal have to be compatible to benefit. For example, 4K is a high resolution, but you won't enjoy that clarity watching standard 1080p FHD TV, which has a lower resolution.


Pixel Resolution

The resolution is how many pixels make up a screen. Generally, the greater the number of pixels, the more detailed the image. This can be measured in vertical lines of resolution, such as Ultra HD 4K and 8K, or horizontal lines, such as HD Ready 720p or Full HD 1080p.


Progressive scan / interlaced

Progressive scan draws the entire frame, rather than the interlaced method of the odd lines and then the even lines. This gives a very stable and clear picture. Nowadays, all TVs are progressive scan. In fact, the 'p' in 720p and 1080p stands for 'progressive'. However, interlaced signals are still used, such as 1080i ('i' for interlaced) used for many HDTV broadcasts in the UK. These have to be 'de-interlaced' by your TV's processing chip and how well it does it has an effect on the final picture quality though, however it's pretty subtle.


For true cinema-style impact at home, nothing beats a projector! Plus, in recent years the quality has taken a big jump up, whilst prices have come down. There are some practical drawbacks, though; for example you really need a dark room to get the absolute best performance, but we think it's worth the effort. If you're not convinced, every store has projectors set up in their demo room, ready to blow you away (see projector – DLP / LCD / LCoS). Whether you want a projector that sits close to the front of a room, or one that operates better in brighter rooms, there’s one for you.

Projector – DLP and DLP 3

The most commonly used type of projector available; the lamp shines a beam through a spinning colour wheel of red blue and green onto a chip covering over 2 million tiny mirrors. Each mirror represents one pixel, and is capable of pivoting towards or away from the light depending on how much brightness or colour is needed – they can do this at up to 5,000 times per second! This minuscule mosaic of colours and shades is our picture, which is then sent through a lens and onto the screen. More sophisticated DLP systems use 3 chips, each with their own colour wheel; the light is then recombined using a prism before being sent to the screen.

Projector - Laser

Laser projectors are a type of Solid State Light (SSL) projector and do away with conventional light sources (bulb) altogether. This is replaced by laser diodes. The main advantage this brings is longer life, but there are also import advantages in the quality of light over time. While bulb-based projectors gradually deteriorate over time, laser diode ones stay every bit as crisp as when they were new.

Projector - LCD

One of the original forms of digital projector; it creates an image by breaking a beam of light into its 3 primary hues before shining each one through a tiny LCD screen that displays the picture. The 3 hues are then recombined inside a prism before being beamed onto your screen.

Projector - LCoS

LCoS stands for Liquid Crystal over Silicone. The light from the lamp is split into red, green and blue. The colours are then shone onto micro-devices, which contain liquid crystals atop a reflective surface. When an electric charge is administered, the liquid crystals alter their shape, and act like filters that control how much light hits the reflective surface according to desired brightness or contrast. The complete image is then recombined and projected onto the screen. Clever stuff.

Projector - LED

LED projectors usually work alongside DLP technology (see above) but use an LED lamp rather than conventional bulb. This has the advantage of longer life and also a more consistent quality of light over time.

Pure Audio

Pure audio is one of the highest quality ways of enjoying High Definition music. What's more, you may already have all the playback equipment required; without even knowing it! The format used is Blu-ray so a Blu-ray player connected via HDMI to an AV receiver will give you direct access to this great HD audio format. The vast majority of recordings also offer the option of surround sound. Finally, you can usually switch between stereo, 5.1 and 7.1 channels via the colour 'fastext' buttons on your Blu-ray remote.

Pure Direct (Source Direct)

Pure Direct, Source Direct or simply ‘Direct’, is a mode found on many pieces of hi-fi and AV equipment that enables you to enjoy the very best sound quality. Essentially, this mode bypasses many of the controls, such as bass, treble and balance controls, to give you a ‘purer’ signal. As this method shortens the signal path the information takes on its journey through an amplifier, it also benefits the purity of the sound in that respect.


PVR (personal video recorder)/DVR (digital video recorder)

A PVR is basically a dedicated TV-recording box. The Sky+ box is one example, but you can buy PVRs compatible to almost any TV system, including Freeview, Freesat and YouView. The main feature that distinguishes these from DVD/HDD recorders is that they record exact copies of the original broadcast, meaning recordings look exactly the same as live TV. They also tend to be easier to use with regards to features like pausing live TV. Ultimately, if you're not bothered about recording programmes to DVD, you'll probably be better off with a PVR.


QLED stands for Quantum-Dot Light Emitting Diode and is Samsung’s high-end TV technology. QLED is the culmination of Quantum Dot technology (see below). It’s important to know that QLED is not related to OLED but more a highly advanced version of LED TV, with the advantage of Quantum Dot technology. QLED TVs are renowned for their vivid colour and bright image quality, making the image truly ‘pop’ from the screen.

Quantum Dots

Quantum dots are incredibly small nano-crystals, which are smaller than a billionth of a metre in size. These dots lie in front of a blue LED backlight, and filter the light as it comes through.

The size of each dot is related to the colour of light that the pixel emits, the amount of light that it produces and how often it is produced.

This technology allows manufacturers to produce TVs with much higher peak brightness and a big improvement in colour accuracy, leading to purer whites and precise colours.


RDS (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.


An amplifier that also comes with a radio tuner on board. There are stereo receivers, however they are not as common as standard amplifiers. More frequently, such a combination is found on a home cinema amplifier. In fact, it’s generally safe to assume that when someone says “receiver” they mean an AV receiver (see AV Receiver) specifically.

Recorders (DVD / Blu-ray)

If you want to copy TV programmes or home movies onto a physical disc, a recorder is your best option. Dedicated disc recorders are rarely available these days, but the functionality is more often found in more advanced machines that can also record to a hard disk drive. Much like shop bought DVDs, you will also be able to read in standard definition. Blu-ray recorders give you the flexibility of both DVD and Blu-ray playback, as well as being able to record HD directly onto a Blu-ray disc.

Response time (TV)

Time taken for screen to go from black to white and back to black again, measured in milliseconds. A small figure means that there is a quicker response time, giving images a cleaner, clearer appearance with fast motion sequences. Like contrast ratio, this specification is now quoted less often by manufacturers.


Like DVD-Audio, this is another physical audio technology, which promised extremely high quality replay, allied to potential surround sound mixes. And like DVD-Audio, it didn't really catch on. That's not to say it doesn't work. Results can be spectacular, if you can find the right equipment. Hardware is not so much of a problem as a surprising number of Blu-ray players support the discs. SACD uses a very different technology from CD or DVD-Audio, implementing a one-bit delta-sigma modulation process known as Direct Stream Digital (DSD), with a very high sampling rate of 2.8224 MHz (see sample rate below). This is 64 times the sampling rate used in making compact disc, hence the improved sound quality.

Sample Rate

In real life sound is constantly changing. To create a digital representation of this sound we have to take a number of “snapshots” - or samples - which, when played back, sound like the original sound. On CDs this is 44,100 times per second (44.1kHz). A higher sample rate gives an even more accurate recreation of the original sound, with high-end network music players and DACs playing back material with sample rates of 192 kHz or more.

SCART (Syndicat des Constructeurs d'Appareils Radiorécepteurs et Téléviseurs)

SCART used to be the most common standard for connecting audio-visual equipment together. With its 21-pin adaptor, SCART was a nice simple, analogue solution for carrying audio and visual signals. This has been surpassed by HD digital alternatives, mainly HDMI.

Sensitivity (speakers)

Sensitivity is a measurement of how efficient a speaker is. It gives you an indication of how easy a particular model will be to drive compared to another. The figure is calculated by inputting a speaker with 1 Watt of white noise and measuring the volume in decibels (dB) from 1 metre away. The higher the number, the louder the speaker with the same input power. Above 89dB and the loudspeakers will be a breeze to drive. If the figure is low - anything below 85dB - get yourself a powerful amp as the speakers will need power aplenty to really sing.


A server is the name given to a piece of (generally) network-enabled equipment that stores your media. At its heart you'll find a hard disc drive (see Hard disk drive) that stores the information.

Smart TV

Very similar in principle to your smartphone, Smart TVs come ready-equipped with internet capability. Once connected to your router (usually wirelessly) they will give you access to a plethora of different apps. Content varies from brand to brand, and model to model, but generally you get social media apps like Facebook, Twitter and YouTube, plus a full web browser and access to catch-up services such as BBC iPlayer and on-demand services such as Netflix. Some also include interactive features such as face recognition along with voice and motion control, but these are only available on certain models.

Smart Home

Smart Home takes many functions found around your home and puts them under control ‘smart’ control – usually via your smartphone or tablet. These include door locks, cameras and alarms, plus smart lighting, power supplies and heating control. Many Audio/Visual components also come under this category (see network streaming).

Soundbar (TV)

One of the most popular additions to the home-cinema market, a TV soundbar consists of two or more amplified speakers built into a long, bar-shaped chassis designed to fit snugly under or above your television. Connections vary from model to model (usually optical and/or HDMI), but their primary purpose is to replace the sound of your TV's speakers for a decent boost in sound. You can connect almost any AV or hi-fi component into a soundbar, even your portable player. More sophisticated models come with separate (and sometimes wireless) subwoofers for extra bass, Bluetooth connectivity, as well as simulated surround sound or even rear speakers.

Sound base (TV)

A sound base works on a similar principle to a soundbar (see soundbar) but is encased within a deeper cabinet that's designed to fit beneath your TV. These usually have enough cabinet capacity to produce lower frequencies, meaning they usually do not need a separate subwoofer.


This is the three-dimensional audio picture a pair of speakers paint. When correctly set up a system should create such a soundstage, where sound doesn't appear to emanate from the speakers themselves, but around them, with musicians placed within this stage. A classic example is to have the lead vocalist positioned centre stage, so his or her voice will appear to come from between the two speakers.

Surround Sound

Used primarily for watching movies or gaming, a typical surround sound setup requires a home cinema amplifier and a 5.1 (or greater) speaker set, meaning five speakers and one subwoofer. The speakers are placed in specific locations to create an ambient illusion of being immersed in the movie or game. A pair of speakers, one on either side of the TV or projector screen, takes care of music and the main breadth of sound effects. A centre speaker above or below the screen deals almost exclusively with dialogue, and another pair of speakers at the back of the room or behind the viewing position handles atmospheric sounds, or anything that goes on “behind” the main action. As bass is usually considered non-directional, the subwoofer has greater flexibility for placement, however certain acoustic properties of a room can affect the sound (try moving the sub around to test for yourself). Depending on the size of your room and AV receiver model, you may also add two more speakers at the front or sides to make 7.1 (seven speakers, one sub) 9.2 (two more speakers and an extra sub), or even more.


An antiquated form of video cable, S-Video means separate video. It carries the video data as two separate signals (brightness and colour). Due to the fact S-Video could only send standard definition, it is now uncommon to feature this connection on video equipment.


THX was originally founded as part of Lucasfilm to ensure that the soundtrack for Star Wars: Return of the Jedi would sound up to George Lucas’ standards in cinemas. The company has since become its own separate entity, which tests home cinema kit against its exacting standards. There are two levels of THX-certification, Select2 - for small to medium rooms - and Ultra2 - for large rooms. Both of these also have 'Plus' variants, which add extra processing to make sure you get a balanced sound at all volumes, not just full whack!

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 (sound)

Basically a technical term for a sudden loud sound, usually one whose volume "cuts through" everything else, like a snare drum for example. These are a really good test of a system's responsiveness; the transient sound should be louder without drowning out everything else.



LCD TVs are the more basic version of LED TV and now largely replaced by this newer technology. They are made up of a film of crystals that twist to let through the right colour from the white backlight that sits behind them. This backlight was traditionally a fluorescent lamp, but now is more usually made up of energy-efficient LEDs. A set using these is usually known as an LED TV, although the core technology is the same as fluorescent lamp models.



LED TV is actually just a development of the conventional sleek LCD flat screens we all know and love (see TV- LCD). LED TVs are basically LCD TVs with one significant difference - they use Light Emitting Diodes (LED) to backlight the screen. This tends to make them thinner and brighter than conventionally lit LCD TVs.



OLED (Organic Light-Emitting Diode) is an advanced form of TV technology that’s used in some of the finest TVs on sale. Unlike LED, which uses backlights shone through groups of pixels, each OLED pixel is individually illuminated. This gives OLED TVs stunning levels of contrast as a bright white pixel can be directly next to a pitch-black one – something almost impossible to achieve with LCD/LED TVs. This means black levels are far better than LED TVs and ‘inky’ deep.


QLED stands for Quantum-Dot Light Emitting Diode and is Samsung’s high-end TV technology. QLED is the culmination of Quantum Dot technology. Rather than using photolumniescent quantum dots, however, it uses electroluminescent nanoparticles. Putting the ‘electro’ into quantum dot tech means that light is supplied directly to the display, giving purer colour, deeper blacks and greatly improved contrast levels.


TV tuner - analogue

With the digital switchover long since passed, you might wonder why analogue tuners are still on this list. Although you won't pick anything up through an aerial from one of these, they are still sometimes used for systems like the Sky Magic Eye, which allow you to watch your Sky box in another room. Devices such as these use what’s called ‘modulation’ to transmit a video signal through an aerial lead.


TV tuner - digital

These days all TVs have a digital aerial tuner. In the UK, these are named DVB-T2 (terrestrial), DVB-T2 (HD terrestrial), DVB-S (satellite), DVB-S2 (HD satellite), DVB-C (cable) and DVB-C2 (HD cable). The free-to-air versions are called Freeview (aerial) and Freesat (satellite). There are other services that combine a digital tuner with Smart internet content, such as Freetime, Freeview Play and YouView. It’s worth noting that a TV with a DVB-S2 tuner built-in doesn’t automatically feature Freesat as the TV companies require a license for this.


TV tuner - Twin

Having two tuners means you can record two programmes at the same time, or watch one and record the other. This feature is most commonly found on PVRs and HDD recorders (see PVR (personal video recorder)/DVR (digital video recorder), but some TVs have it too. Bear in mind that with TVs you usually need to buy a separate USB storage device to make recordings.


Tweeter (speaker)

Often found at the top of loudspeakers, the tweeter is a drive unit that handles all the higher frequencies that need to be reproduced. Usually dome-shaped, more high-end variations include ribbon designs. The design of the tweeter has a great impact on how the music sounds – for example, metallic tweeters produce a crisp, almost metallic treble, while soft dome tweeters are usually more subtle.


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UPnP (Universal Plug 'n' Play) or DLNA (Digital Living Network Alliance) are methods of sharing digitally stored information between compatible devices through a shared internet connection. For example, if you want to show your friends your latest holiday snaps, you can access them from your computer and display them on your Smart TV in all their glory! UPnP determines the devices compatibility and their role in the transfer i.e. which device will be sending or receiving data. DLNA has its own restrictions to govern the type of information that will be sent, such as music or video files. With more DLNA-compatible devices becoming available every year, including Blu-ray players and smartphones, you can integrate your media files with your home cinema like never before!


Upsampling (sound)

A technique invented by audio technicians and used in some specialist DACs to improve the quality of audio replay. In essence it means generating more pieces of information than the digital file contains. This is done by adding more samples, effectively creating a smother, more natural sound wave. Very clever indeed.


Upscaling (picture)

When the picture you want to watch isn't the same resolution as your TV, it needs to be upscaled to fit; otherwise, it would be a tiny image in the middle of the screen with swathes of black all around. The process of upscaling is effectively guessing new pixels to fill in the gaps. Some systems, such as those found in higher-end Blu-ray players, make more sophisticated guesses (or 'interpolations' to use the techy term) than others, resulting in pictures that appear sharper from the same DVD. A lot of units advertise their '4K upscaling’ or ‘8K upscaling’ technology. This is exactly the same process as what's described above, but for the 4K or the latest 8K Ultra HD TVs. With such a set it's more important to make sure you have high quality upscaling, as a lot of what you watch will still be either standard definition, regular 1080p HD or 4K UHD. Also bear in mind, all HD and Ultra HD TVs and projectors will also upscale the resolution of a video (with varying degrees of quality).


Voice control

Usually tied in with Smart Home technology, voice control is now popular across a wide range of AV products. Voice control can either be an exclusive system tied to a particular product – as a TV. More commonly, though, voice control devices tie in with Amazon Alexa, Google Assistant or Apple Siri. The device either works with one of these devices (such as an Amazon Dot), or has the technology built-in.


Voice controlled speakers

At the most basic level, voice controlled speakers use voice recognition to select the music you want to listen to – often tying in with services such as Spotify and Tidal. The vast majority of voice-operated speakers go much further, though. Used in a ‘smart home’, they can also control a wide range of other functions such as lighting, heating, TV and even ordering goods over the Internet.



A measurement of power. In hi-fi parlance it tells you how powerful your amplifier is or the amount of power your speakers can handle. Remember power doesn't always equate to quality, so a powerful amp isn't necessarily the best. Sometimes manufacturers tweak the figures by quoting at lower impedance or at a high amount of THD (total harmonic distortion), which should always be below 0.1% for accurate power ratings. We always aim to quote the most accurate "real world" power rating for amplifiers in the specifications on our website, so you can make fairer comparisons.



With wireless routers now included with every broadband service, not to mention beaming through coffee houses throughout the land, Wi-Fi has reached near ubiquity. But what does wireless Internet and networking mean for your TV, hi-fi and home cinema? With more and more units offering connection to the web, built-in Wi-Fi means easy wireless access to your existing internet connection. Besides the web, a network connection is needed for those fancy smartphone and tablet remote control apps. All in all, from TVs to home cinema amplifiers, built-in Wi-Fi is a very useful feature to have!


Woofer (speaker)

A woofer is the driver in a loudspeaker that looks after the lower and mid frequencies. In most speakers this is actually a mid/bass driver, with the treble handled by a tweeter (see tweeter). Larger three-way speakers have two drivers, one for bass tones and one for the mid.



YouView is a rival system to Freeview and Freesat and gives you the best of both worlds by offering free to view digital HDTV and a wide range of catch-up TV services. It makes catching up on TV particularly easy by offering a 'scroll back' programme guide.



XLR is a balanced audio connector usually found in professional audio equipment. You might recognise it as a microphone lead. An XLR is also a great way of connecting your premium hi-fi setup together. XLR cables provide a superior connection as they include an extra pin to eliminate "ground hum".


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