AV receiver

Last updated January 07, 2024

An audio/video receiver (AVR) is a consumer electronics component used in a home theater. Its purpose is to receive audio and video signals from a number of sources, and to process them and provide power amplifiers to drive loudspeakers and route the video to displays such as a television, monitor or video projector. Inputs may come from a satellite receiver, radio, DVD players, Blu-ray Disc players, VCRs or video game consoles, among others. The AVR source selection and settings such as volume, are typically set by a remote controller.^[1]

Usage

The term "receiver" basically refers to an amplifier, typically at least a two-channel stereo model, that has a built-in radio tuner. With A/V receivers, the basic functionality is to receive an audio signal, amplify the audio signal to drive multiple speakers, and allow pass-through of the corresponding video signal to a display device such as a projector or a television. The receiver performs tasks that would otherwise require numerous separate pieces of equipment, such as preamplifiers, equalizers, multiple power amplifiers, and so on.

As home entertainment options expanded in the 1980s and 1990s, so did the role of the receiver. The ability to handle a variety of digital audio signals was added. More amplifiers were added for surround-sound playback. Video switching was added to simplify changing from one device to another, though this role diminished again once TVs began supporting multiples of the same type of input connector.

The term audio/video receiver (AVR) or Home Theater Receiver is used to distinguish the multi-channel audio/video receiver (home theater receiver) from the simpler stereo receiver, though the primary function of both is amplification.

AV receivers may also be known as digital audio-video receivers or digital media renderers.^[2]

The AV receiver is classified as an audio frequency electronic amplifier. But with the addition of several features in the 2000s, AV receivers in the 2010s generally have significant additional functionality.

Features

Channels

Stereo receivers have two channels of amplification (thus two separate amplifiers), while AV receivers may have more than two. The standard for AV receivers is five channels of amplification (thus five separate amplifiers), usually referred to as 5.1 receivers. This provides for a left, right, center, left surround sound and right surround sound speaker to be powered by the receiver.

In the 2010s, 7.1 receivers became more common and provide for two additional surround channels, left rear surround and right rear surround. The ".1" refers to the LFE (low-frequency effects/bass) channel, the signal of which is usually sent to an amplified subwoofer unit. 5.1 and 7.1 receivers do not usually provide amplification for this channel. Instead, they provide a line level output. The user then either buys a separate monophonic power amp for their subwoofer or obtains a powered subwoofer cabinet, which contains an integrated power amplifier.

Amplifier power

Audio amplifier power, normally specified in watts, is not always as significant as it may seem from the specification. Due to the logarithmic nature of human hearing, audio power or sound pressure level (SPL), must be increased by ten times to sound twice as loud. This is why SPL is measured on a logarithmic scale in decibels (dBs). An increase of 10dBs results in a perceived doubling of loudness. Another complication with human hearing is that as the SPL decreases the perceived volume of the low and high frequencies decreases faster than the central frequencies around 2 kHz.^[3]

There are different standards for rating amplifier power depending on country, manufacturer, and model. Other factors also come into play: distortion, headroom, speaker efficiency. As well, some lower-price point manufacturers advertise the peak power of an amplifier, rather than its root mean square (RMS) power. Thus, it is possible for an amplifier with a specified lower power to sound louder than an amplifier with a specified higher power. Because of these factors, it is not easy to compare the perceived loudness of amplifiers solely from their specified power in watts.

Decoders

AV receivers usually provide one or more decoders for sources with more than two channels of audio information. This is most common with movie soundtracks, which use one of a variety of different types of encoding formats.^[4]

The first common soundtrack format was Dolby Pro Logic, a surround sound processing technology. This format contains a center channel and a surround channel mixed into the left and right channels using a process called matrixing, providing a total of four channels. Receivers with Dolby Pro Logic decoders can separate out the center and surround channels from the left and right channels.

With the introduction of the DVD, the Dolby Digital format became a standard. Dolby Digital ready receivers included inputs and amplifiers for the additional channels. Most current AV receivers provide a Dolby Digital decoder and at least one digital S/PDIF input which can be connected to a source which provides a Dolby Digital output.

A somewhat less common surround sound decoder called DTS is standard on current AV receivers.

When Dolby Labs and DTS introduced technologies to add a rear center surround channel, these technologies found their way into AV Receivers. Receivers with six amplifiers (known as 6.1 receivers) will typically have both Dolby and DTS's technologies. These are Dolby Digital EX and DTS ES.

Dolby introduced Dolby Pro Logic II to allow stereo sources to play back as if they were encoded in surround sound. DTS introduced a similar technology, Neo:6. These decoders have become common on most current receivers.

As the number of playback channels was increased on receivers, other decoders have been added to some receivers. For example, Dolby Labs created Dolby Pro Logic IIx to take advantage of receivers with more than five channels of playback.

With the introduction of high definition players (e.g. Blu-ray Disc and HD DVD), yet more decoders have been added to some receivers. Lossless Dolby TrueHD and DTS-HD Master Audio decoders are available on many receivers.

While Dolby Digital has been the standard for television and video games, Dolby Digital Plus has been adopted for online streaming services such as Netflix, and adds a much higher bit rate and can support more channels.

Dolby Atmos and DTS:X adds in ceiling height channels.

DSP effects

Most receivers offer specialized digital signal processors (DSP) made for handling various presets and audio effects. Some may offer simple equalizers and balance adjustments to complex DSP audio field simulations such as "Hall", "Arena", "Opera", etc. that simulate or attempt to replicate the reverb as if the audio were being played in the places through use of surround sound and echo effects.

AV inputs/outputs

There are a variety of possible connections on an AV receiver. Standard connectors include:

Analog audio (RCA connector, or occasionally XLR connector)
Digital audio (S/PDIF; TOSLINK or RCA terminated coaxial cable)
Composite video (RCA connector)
S-Video
SCART video (primarily used in Europe and very uncommon in many other parts of the world)
Component video
HDMI
USB (usually involves special computer circuitry to read video formats from a file system)

Analog audio connections usually use RCA plugs in stereo pairs. Inputs and outputs are both common. Outputs are provided mainly for cassette tape decks.

Analog audio connections using XLR (Balanced) connectors are uncommon, and are usually found on more expensive receivers.

Some receivers are also equipped with phono inputs, for connecting a turntable with a magnetic cartridge, although many receivers are lacking this input. In the last years, since vinyl players are gaining popularity, there are some manufacturers of A/V receivers which are offering a phono input on some models. Some receivers also have a selector for either MM/MC cartridge type, or even an impedance selector for cartridge, or some May have more than one Phono input. This feature is mainly offered to allow people owning a turntable to connect it and listen to their vinyl collection. Most receivers will only play in stereo, either front or main speakers, but some receivers may play on all speakers depending on the manufacturer and model.

Digital connections allow for the transmission of PCM, Dolby Digital or DTS audio. Common devices include CD players, DVD players, or satellite receivers.

Composite video connections use a single RCA plug on each end. Composite video is standard on all AV receivers allowing for the switching of video devices such as VHS players, cable boxes, and game consoles. DVD players may be connected via composite video connectors although a higher bandwidth connection is recommended.

S-Video connections offer better quality than composite video. It uses a DIN jack.

SCART connections generally offer the best quality video at standard-definition, due to the use of pure RGB signalling (although composite and S-Video may alternatively be offered over a SCART connector). SCART provides video and audio in one connection.

Component video has become the best connection for analog video as higher definitions such as 720p have become common. The YPbPr signalling provides a good compromise between resolution and colour definition.

HDMI has become the de facto standard for passing video and audio on AV receivers. Features supported through HDMI may include pass-through of 4K, 8K, and HDR video, audio return channel (ARC), enhanced audio return channel (eARC), variable refresh rate (VRR), and pass-through of object-based audio formats such as Dolby Atmos and DTS:X. ^[5]

Video conversion and upscaling

Some AV Receivers can convert from one video format to another. This is commonly called upconversion or transcoding. A smaller number of receivers provide for de-interlacing of video signals. For example, a receiver with upconversion, deinterlacing and upscaling can take an interlaced composite signal at 480i (480 lines per frame sent as a field of 240 even numbered lines 0,2,4,8...478 followed by a field of 240 odd numbered lines 1,3,5,...479) and convert it to component video while also deinterlacing and upscaling it to a higher resolution such as 720p (720 lines per frame with all lines in normal sequence 0,1,2...719).

Radio on AVRs

AV receivers though primarily used for amplification may or may not have an inbuilt AM/FM radio tuner among other features such as LAN connectivity for various Internet applications and some with multi-room audio solutions.

Even though some AVRs may have an AM/FM tuner it is not a primary or mandatory function as an AVR still remains an amplifier.

Some models have HD Radio tuner. Also some models May have a digital Radio, DAB/DAB+, for some markets.

Some models have Internet radio and PC streaming access capabilities with an Ethernet port.

Related Research Articles

SCART is a French-originated standard and associated 21-pin connector for connecting audio-visual (AV) equipment. The name SCART comes from Syndicat des Constructeurs d'Appareils Radiorécepteurs et Téléviseurs, "Radio and Television Receiver Manufacturers' Association", the French organisation that created the connector in the mid-1970s. The related European standard EN 50049 has then been refined and published in 1978 by CENELEC, calling it péritelevision, but it is commonly called by the abbreviation péritel in French.

Dolby Digital, originally synonymous with Dolby AC-3, is the name for a family of audio compression technologies developed by Dolby Laboratories. Called Dolby Stereo Digital until 1995, it is lossy compression. The first use of Dolby Digital was to provide digital sound in cinemas from 35 mm film prints. It has since also been used for TV broadcast, radio broadcast via satellite, digital video streaming, DVDs, Blu-ray discs and game consoles.

S/PDIF is a type of digital audio interface used in consumer audio equipment to output audio over relatively short distances. The signal is transmitted over either a coaxial cable or a fiber-optic cable with TOSLINK connectors. S/PDIF interconnects components in home theaters and other digital high-fidelity systems.

<span class="mw-page-title-main">RCA connector</span> Electrical connector used for analog audio and video

The RCA connector is a type of electrical connector commonly used to carry audio and video signals. The name RCA derives from the company Radio Corporation of America, which introduced the design in the 1930s. The connector’s male plug and female jack are called RCA plug and RCA jack.

A DVD player is a device that plays DVDs produced under both the DVD-Video and DVD-Audio technical standards, two different and incompatible standards. Some DVD players will also play audio CDs. DVD players are connected to a television to watch the DVD content, which could be a movie, a recorded TV show, or other content.

Home cinema, also called home theaters or theater rooms, are home entertainment audio-visual systems that seek to reproduce a movie theater experience and mood using consumer electronics-grade video and audio equipment that is set up in a room or backyard of a private home. Some studies show that films are rated better and generate more intense emotions when watched in a movie theater, but convenience is a major appeal for home cinemas. In the 1980s, home cinemas typically consisted of a movie pre-recorded on a LaserDisc or VHS tape; a LaserDisc Player or VCR; and a heavy, bulky large-screen cathode ray tube TV set, although sometimes CRT projectors were used instead. In the 2000s, technological innovations in sound systems, video player equipment and TV screens and video projectors have changed the equipment used in home cinema set-ups and enabled home users to experience a higher-resolution screen image, improved sound quality and components that offer users more options. The development of Internet-based subscription services means that 2020s-era home theatre users do not have to commute to a video rental store as was common in the 1980s and 1990s.

DVD-Audio is a digital format for delivering high-fidelity audio content on a DVD. DVD-Audio uses most of the storage on the disc for high-quality audio and is not intended to be a video delivery format.

Nakamichi Corp., Ltd. is a Japanese consumer electronics brand that originated in Japan and gained a name from the 1970s onwards for innovative and high quality audio cassette decks. Nakamichi is a subsidiary of Chinese holding company Nimble Holdings.

Dolby Pro Logic is a surround sound processing technology developed by Dolby Laboratories, designed to decode soundtracks encoded with Dolby Surround. The terms Dolby Stereo and LtRt are also used to describe soundtracks that are encoded using this technique.

High-Definition Multimedia Interface (HDMI) is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controller, to a compatible computer monitor, video projector, digital television, or digital audio device. HDMI is a digital replacement for analog video standards.

DTS, Inc. is an American company, DTS company makes multichannel audio technologies for film and video. Based in Calabasas, California, the company introduced its DTS technology in 1993 as a competitor to Dolby Laboratories, incorporating DTS in the film Jurassic Park (1993). The DTS product is used in surround sound formats for both commercial/theatrical and consumer-grade applications. It was known as The Digital Experience until 1995. DTS licenses its technologies to consumer electronics manufacturers.

Dolby Digital Plus, also known as Enhanced AC-3, is a digital audio compression scheme developed by Dolby Labs for the transport and storage of multi-channel digital audio. It is a successor to Dolby Digital (AC-3), and has a number of improvements over that codec, including support for a wider range of data rates, an increased channel count, and multi-program support, as well as additional tools (algorithms) for representing compressed data and counteracting artifacts. Whereas Dolby Digital (AC-3) supports up to five full-bandwidth audio channels at a maximum bitrate of 640 kbit/s, E-AC-3 supports up to 15 full-bandwidth audio channels at a maximum bitrate of 6.144 Mbit/s.

A home theater in a box (HTIB) is an integrated home theater package which "bundles" together a combination DVD or Blu-ray player, a multi-channel amplifier, speaker wires, connection cables, a remote control, a set of five or more surround sound speakers and a low-frequency subwoofer cabinet. Manufacturers also have come out with the "Sound Bar," an all in one device to put underneath the television and that contains all the speakers in one unit.

Dolby TrueHD is a lossless, multi-channel audio codec developed by Dolby Laboratories for home video, used principally in Blu-ray Disc and compatible hardware. Dolby TrueHD, along with Dolby Digital Plus (E-AC-3) and Dolby AC-4, is one of the intended successors to the Dolby Digital (AC-3) lossy surround format. Dolby TrueHD competes with DTS's DTS-HD Master Audio, another lossless surround sound codec.

The Sony BDP-S1 is a first generation Blu-ray Disc (BD) player and is the first such player released in North America. It was originally scheduled for release in the United States on August 18, 2006 with a MSRP of $999.95. Sony had postponed the release date of this player several times and it was released on December 4, 2006.

<span class="mw-page-title-main">DTS-HD Master Audio</span> Lossless audio codec for home theater

DTS-HD Master Audio is a multi-channel, lossless audio codec developed by DTS as an extension of the lossy DTS Coherent Acoustics codec. Rather than being an entirely new coding mechanism, DTS-HD MA encodes an audio master in lossy DTS first, then stores a concurrent stream of supplementary data representing whatever the DTS encoder discarded. This gives DTS-HD MA a lossy "core" able to be played back by devices that cannot decode the more complex lossless audio. DTS-HD MA's primary application is audio storage and playback for Blu-ray Disc media; it competes in this respect with Dolby TrueHD, another lossless surround format.

Audio connectors and video connectors are electrical or optical connectors for carrying audio or video signals. Audio interfaces or video interfaces define physical parameters and interpretation of signals. For digital audio and digital video, this can be thought of as defining the physical layer, data link layer, and most or all of the application layer. For analog audio and analog video these functions are all represented in a single signal specification like NTSC or the direct speaker-driving signal of analog audio.

Home audio systems refer to audio consumer electronics designed for home entertainment, such as integrated systems like shelf stereos and music centers, as well as individual components like loudspeakers and surround sound receivers. The evolution of home audio began with Edison's phonograph, transitioning from monaural to stereophonic sound in the 1950s and 60s. The term "hi-fi" emerged, highlighting sound accuracy and minimal distortion. Audio equipment evolved from large wooden cabinets to compact units. The 1970s introduced enhancements like quadraphonic sound and technologies like Dolby Pro Logic. The 1970s and 1980s also saw the rise of component-based stereo systems. Cassette decks became a staple in the 1970s. Integrated systems, termed "music centers" gained popularity in the 1980s. Table systems and compact radio receivers emerged as entertainment devices, with some offering features like cassette players and CD functionalities. Audiophile systems prioritize high-quality music formats and specialized equipment like premium turntables, digital-to-analog converters, and other high-end devices, with some enthusiasts preferring the unique sound characteristics of vinyl records and vacuum tubes. Modern systems often emphasize home cinema applications to enhance the audio experience beyond standard TV speakers.

TOSLINK is a standardized optical fiber connector system. Also known generically as optical audio, its most common use is in consumer audio equipment, where it carries a digital audio stream from components such as CD and DVD players, Digital Audio Tape recorders, computers, and modern video game consoles, to an AV receiver that can decode two channels of uncompressed pulse-code modulated (PCM) audio or compressed 5.1/7.1 surround sound such as Dolby Digital or DTS Surround System. Unlike HDMI, TOSLINK does not have the bandwidth to carry the uncompressed versions of Dolby TrueHD, DTS-HD Master Audio, or more than two channels of PCM audio.

Various accessories for the PlayStation 2 video game console have been produced by Sony, as well as third parties. These include controllers, audio and video input devices like microphones and video cameras, and cables for better sound and picture quality.

References

↑ Audio-Video Engineering. Nirali Prakashan. ISBN 978-81-906396-7-5 . Retrieved 14 December 2019.
↑ "Organization". DLNA. Retrieved 2019-12-14.
↑ Self, Douglas (2013). Audio Power Amplifier Design. Taylor & Francis. ISBN 978-1-136-12381-8 . Retrieved 14 December 2019.
↑ zinia, kira (5 November 2019). "Succeed in the Business of Sound By Using An Audio Visual Rental Software". Reservety. Retrieved 14 December 2019.
↑ "HomeTheaterReview's AV Receiver Buyer's Guide (November 2020 Update) - HomeTheaterReview". hometheaterreview.com. 2020-11-13. Retrieved 2021-04-08.

External links

Block Diagram of a typical Receiver Archived 2011-06-04 at the Wayback Machine
HDMI switch guide for audio video switching

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
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[1] Audio-Video Engineering. Nirali Prakashan. ISBN 978-81-906396-7-5 . Retrieved 14 December 2019.

[2] "Organization". DLNA. Retrieved 2019-12-14.

[3] Self, Douglas (2013). Audio Power Amplifier Design. Taylor & Francis. ISBN 978-1-136-12381-8 . Retrieved 14 December 2019.

[4] zinia, kira (5 November 2019). "Succeed in the Business of Sound By Using An Audio Visual Rental Software". Reservety. Retrieved 14 December 2019.

[5] "HomeTheaterReview's AV Receiver Buyer's Guide (November 2020 Update) - HomeTheaterReview". hometheaterreview.com. 2020-11-13. Retrieved 2021-04-08.

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