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.