The AV receiver is the epicenter of the home theater, so it’s worth not less serious than choosing a half-meter plasma TV or multichannel acoustics.
The Receiver for Turntable
Originally, the term “best receiver for turntable” in radio engineering termed simply a radio receiver, that is, a tuner with a built-in amplifier. Today, this sophisticated device is capable of handling digital and analog multichannel sound signals as well as video signals and serves as the home theater center. A simple radio tuner in receivers now remains something like a tribute to the past.
How to build a sound system
The AV receiver performs three key functions: decoding, gaining and switching. You can add a fourth, decorative – the development of modern equipment is unthinkable without the participation of designers.
The main function of the AV receiver
Let’s talk about the key function that the AV receiver performs. First of all, about working with sound. In the case of analog sound, the scheme is simple: the analog stereo or multi-channel output of the CD, DVD player, selected Blu-ray player or any other source is connected to the analog stereo or multichannel input of the receiver. After that the signal amplifies, if necessary, passes through the timbre block or the module of effects, switched and output to the acoustic system.
The scheme is as traditional as the same and outdated: today’s receivers are almost impossible to meet the analog multi-channel input – it is much more convenient to transmit digital multichannel sound through a single cable, in addition, there is little in which modern sources can find such an outlet. Simultaneously with the simplification of the circuit is removed and the problem of ensuring the impedance of analog channels and their separation: for digital decoders, such problems are not relevant.
In this case, all AV receivers have five to six analog stereo audio inputs that are used to connect traditional sources – tuners, CD players, tape recorders and analog video recorders. Not so rarity and the entrance to the recorder.
This option is also possible when the digital-to-analog converter of an expensive SACD or DVD player delivers higher sound quality than a DAC built-in to the receiver: in this case, it is also meant to use an analog rather than a digital connection.
With a digital sound all at the same time and more difficult, and easier. To hear a digital signal in the speakers, it must be converted to analog and transmitted to the power amplifier, it is the low-frequency amplifier, that is, the range of audio frequencies that a person can hear. However, since a single digital cable often transmits multichannel sound and even video, such a signal is required to start decoding.
Tips for building a sound system
There are a number of encoding formats that are divided into two categories by the name of the developer: Dolby Digital and DTS. Both families are close in terms of possibilities and characteristics, and although from a formal point of view, they provide different sound and distribution through channels, the usual listener is unlikely to be able to notice it. Moreover, since all AV receivers, with rare exceptions, are equipped with decoders of both families, it is not practical for the consumer to have a practical meaning in which format the multi-channel movie track is recorded.
For today’s receivers, there is a standard set of decoders: Dolby Digital, Dolby Digital EX, Dolby Digital Plus, Dolby TrueHD, DTS / DTS-ES, DTS 96:24, DTS-HD High-Resolution Audio and DTS-HD Master Audio. Dolby Pro Logic II / IIx / IIz and DTS Neo: 6 decoders can virtually expand the dual-channel multi-channel 5.1 or 6.1 channel.
We will not delve into the characteristics of all these formats – if desired they are easy to find on the Internet. For purely technical reasons, it is considered that the DTS family format sounds a bit better: theoretically, they use a lesser degree of loss of sound compression than Dolby Digital. In this case, the top formats of both families – DTS-HD Master Audio and Dolby Digital TrueHD allow you to encode the sound at all without loss, and they give the same high-quality sound. Also, read an interesting article about listening to a mobile phone.
Audio system building guide
Converting sound to AV receivers is carried out by digital-analog converters with a bit of 24 bits and a sampling rate of at least 96 kHz, while inexpensive models, the frequency is not 192, and 256 kHz, which provides higher sound quality. If you plan to play SACD and DVD-Audio discs with maximum settings, choose models with a sampling frequency of 192 kHz.
For compatibility with old music players, the standard digital optical and coaxial S / PDIF inputs are also installed in the receivers, which can be transmitted as ordinary uncompressed stereo sound (for example, from cd) and multi-channel compressed.
It is always possible to connect analog sources and video consumers: via composite and component inputs, as well as through the S-Video port. Sometimes there are only S-Video outs and components that allow you to view videos, for example, on a morally outdated but high-quality television or projector that does not have digital inputs.
As for the SCART connectors that could transmit analog audio and video, in spite of their former prevalence in European production technology, they are found in modern receivers only in exceptional cases.
Connecting the speaker systems to the receiver is most often carried out through “bananas”: each screw connector employs one cable with a spring-loaded plug, or the bare cable is simply clamped with a screw – or through RCA connectors for a dual-cable connection. Spring clamps are commonly used only in low-cost low-power kits from one box, and they are rarely installed in high-quality receivers because they do not allow the use of cables of the sufficiently large cross-section.
The typical output power of a middle-class DIN receiver is 90-110 W x 5 or 7 channels at nominal impedance (ie, full resistance) of 6-8 ohms. Proceeding from this data, one should select a set of columns, while their impedance must strictly comply with the supported receiver, and the maximum output power should exceed the output power of the amplifier.
On the back of the AV receivers, you can find spring clips or coax connectors for connecting FM / AM radio antennas, as well as additional connectors such as RS-232 for inclusion in multi-room systems, Ethernet for connection to the local area network and playback files from incoming computers, as well as for receiving Internet radio, a USB port for reading multimedia files from removable media, one or more sockets for powering not too powerful neighboring components – for example, DVD / Blu-ray or tape recorder. A modular feature is a port for connecting iPod / iPhone, as well as support for working with the Apple AirPort application (via a wired LAN) to play streaming audio files from Apple’s players.
In order to ensure the correct sound picture in AV-receivers calibration systems are used: it’s no secret that it is not always possible to place all the columns “in science” in the room, which already talks about muffling and other tricks. Automatic calibration systems are designed to solve this problem with the help of a remote measuring microphone alternately installed in the locations of the speaker systems or in the location of the listener’s head.
After the measurements, the special processor counts and then makes the necessary changes in the input of the output signal to one or another column, compensating for the flaws of the location by adjusting the frequency characteristics, volume and delay time. You can also manually adjust the results of automatic adjustment.
The video-functionality of modern AV receivers is not only in pure switching, but it is significantly different in different models. A digital video processor (DSP) is capable, for example, of processing video signals in several variants, changing the picture displayed on the screen to its own taste. He can also scale the image from a video cassette or DVD up to 1080p, and on some models – and above!
In the presence of video ADP, it is possible to digitize the real-time analog video, pushing the received signal to the resolution of high-definition, followed by output to the TV or projector. Of course, direct signaling modes (in the best models, including 3D) via the HDMI c source interface to the consumer are supported. For aesthetes, the receivers are assigned with modes such as HDMI-Thru, in which the video signal is not guaranteed to make the slightest change.
Finally, the detailed settings of the AV receiver can only be made from the remote control and only through the on-screen menu. Despite the seemingly large number of controls even on the cheapest device, they are used only for the simplest functions. Some models boast built-in large screens, but even with their help, it is impossible to make detailed settings, because everything they reflect is enabled modes and some numerical data like the frequency of the radio stations. It is therefore highly desirable to get an idea of the menu on the FullHD screen when choosing. It is FullHD, as separate devices for some really religious reasons do not want to scale their own menu to 1920×1080 pixels and display on such displays a terribly pixelated image.
The spread of prices for AV-receivers is very wide. Conditionally, three main categories of devices can be distinguished: the entry-level (from 300 to 500 dollars), the middle class (from 500 to 1000 dollars) and the premium class (from $ 1000 to infinity). By functionality, quality and price, the upper part of the middle class, from about 800 to $ 1000, can be recognized as the best choice. Cheaper models will definitely lack the functions that are suddenly vital, and more expensive fill their price at the expense of selected audiophile components, specific circuitry and cases of luxurious materials.