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Receiver for speaker system: description, functions, tuning

The receiver for the speaker system is the heart of the home theater. All cables, connections and other components work through it. The device controls audio and video signals from all sources and feeds at least five speakers. The question of how to choose a receiver for an acoustic system may seem extremely difficult, but if the answer is correct, then the reward will be huge. Successfully matched AV-receiver is pleasant to use, and it will allow to use speakers and other components as efficiently as possible.

What is a receiver for an acoustic system? It simultaneously performs the functions of a multichannel amplifier and a surround sound processor. For the most demanding columns and rooms, it is probably better to purchase these components separately. But for most home theaters, the AV receiver will be perfect.

Modern systems widely use the HDMI 1.4 standard, which includes the HDMI Ethernet function, allowing devices to exchange data and Internet connections among themselves, a reverse audio channel that allows the audio signal to be transferred back to the AV receiver, and a micro-connector. Other features include support for 4K and 3D resolution .

Energy-efficient topology of amplifiers

In a conventional AV receiver, AB class amplification is used, which works well, but consumes a lot of energy. There are more effective alternatives. One of the most promising is Class D. The analog signal turns into a sequence of pulses and is used to turn devices on and off, not allowing them to work constantly. Amplifiers and receivers of class G and H are not new, but they are gaining popularity. They use various circuits with relay switching and tracking, which supply the output devices with no more than the voltage required at a given time. Manufacturers are finding ways to make these energy-saving solutions sound better, and they are expected to eventually capture most of the market.

Acoustic system 5.1

The receiver creates 5.1-channel audio in the following way: three speakers in front, two at the back side, and separate for low-frequency effects. However, with the exception of entry-level models, most of them have seven amplification channels. This includes basic 5.1 and two more for volumetric expansion modes. The latter include frontal height, frontal width and rear. Although Yamaha has been making front high-altitude presence channels for some time now, you can find AV receivers that receive high-altitude signals from Dolby Pro Logic II or Audyssey DSX. However, for latitude channels, the only option is the DSX. Ironically, only the rear are supported by DTS-ES or Dolby EX codecs. DPLII and DSX are the only processing modes that reproduce height or width channels.

Are they needed? Height adds a new dimension in some films, but not music. And vice versa, the width of little changes in films and even less in music. The surround back surround can be useful if the surround speakers are not enough to cover a long narrow room. However, additional channels may not justify the costs and hassle of installing speakers in the room.

Low volume, alignment and compression

Founding fathers of modern soundtracks of films decided that each AV receiver, speaker system should be calibrated at a basic level of 85 dB. But most people at home set a lower volume. As practice shows, when decibels fall below the reference level, the human hearing naturally changes. As a result, dialogues become harder to grasp, background sounds disappear and the sound field collapses. In addition, it is likely that the sources connected to the rear panel of the receiver give a different input volume, which requires constant annoying manual adjustments.

Technologies have emerged that are struggling with these problems. THX Loudness Plus (part of Select2 Plus and THX Ultra2 Plus), Dolby Volume and Audyssey Dynamic EQ tend to maintain a consistent tonal balance, exposure and surroundings at a lower volume. Dolby Volume and Audyssey Dynamic Volume also have the ability to align different signal levels from different sources or TV shows and commercials. Both technologies are capable of performing extended dynamic range compression within a specific program. This is similar to the more sophisticated version of the night listening mode for receivers of past years (unfortunately, they are often incompatible with modern surround codecs). Audyssey Dynamic EQ and Dynamic Volume systems are based on the Audyssey MultEQ / 2EQ automatic adjustment and correction technology. When the dynamic volume is turned on, the dynamic equalizer is always activated. However, it is not tied to the overall volume set by Dynamic Volume. All these technologies significantly improve quiet listening. It is desirable to have at least one such system.

Automatic adjustment and room correction are two convenient functions for beginners, which, as a rule, accompany each other. They can be both licensed and proprietary.

Automatic configuration

If the idea of tuning the receiver-acoustics kit fills you with fear, then this can be provided to the automation. Such devices are equipped with a small microphone. After placing the receiver in place of the listener and activating the automatic installation program, it will give test signals and self-tuning. The equipment will determine the size of the speakers, the distance to them and other parameters. This function is intended for beginners.

Correcting the room

The acoustic receiver also allows you to make room corrections in order to correct bass and other sound deficiencies. But remember that these equalizers do not always provide the best sound. But you can always disable the equalizer if the result of the correction does not like it. Some models allow manual fine-tuning.

Many manufacturers use their own settings and room correction systems, but Audyssey versions are most often licensed and considered to be among the best. Audyssey MultEQ measures the response of speakers located in eight positions and combines them with an equalizer in such a way as to optimize the sound in a wide listening area. 2EQ does the same for the three positions. For silent sound, the Aaudyssey Dynamic EQ uses Multeq or 2EQ as the basis, adjusting the frequency response and the balance of the surroundings with increasing and decreasing the signal. Correcting the room, of course, can be useful, but it does not replace the proper placement of speakers and other basic settings. The program is licensed for use in Denon, Integra, Marantz, Onkyo, NAD, etc. Another licensed system of automatic installation and correction of the room is Trinnov, used in Sherwood receivers and sound processors Audio Design Associates.

THX Certification

The THX-certified acoustics receiver has enough power to work with THX-certified speakers for a nominal sound level in rooms of a certain size. These receivers also support the cinema mode, which includes, among other things, a scheme for suppressing excessively bright soundtracks for Re-EQ movies. THX participated in the creation of a 7.1-channel version of Dolby Digital, but most functions are an overlay for existing surround codecs. The standard is beneficial to use in the context of completely THX-certified systems. In other words, with a certified receiver and speakers, you can get all the benefits of compatibility and integration.

Dolby and DTS surround decoding

Surround sound at best is the result of a discrete encoding-decoding process (so-called codec). It is included in the software and decoded in hardware at home, without creating false or derived channels derived from others. The Dolby and DTS formats are the basis of home theater technology.

DTS-HD Master Audio, Dolby TrueHD

These standards provide much more efficient data storage than uncompressed PCM. They reconstruct the master soundtrack bit by bit. In this case, the user receives exactly what the engineer has encoded. To fans of Blue-ray these codecs will be needed in any of their players or AV-receiver. If the home receiver can receive a high resolution PCM signal via HDMI, then it does not need to have a lossless decoding system. Decoding is not the best solution, because it does not allow you to hear so-called secondary audio, such as comments or windows with bonus images that you can call during the main program.

Audio DTS-HD, Dolby Digital Plus

These are the so-called lossy compression formats, because during the encoding-decoding process they omit some data that become inaccessible during playback. But this is done more intelligently (and sometimes at higher data transfer speeds) than in the old Dolby Digital 5.1 and DTS, and as a result, a clean and high-quality sound is obtained.

Dolby EX and DTS-ES Discrete / Matrix

These are upgraded versions of DTS and DD 5.1 with surround back sound. Dolby EX is a 6.1-channel acoustics connection to the receiver, although here, as a rule, one channel is shared between the two systems. It decodes back-surround sound, which does not allow to call it completely discrete. DTS-ES operates in a similar manner, although in this case the rear rear is really independent. These codecs are used in some releases on DVD and Blu-ray.

DTS and DD 5.1

These are the basic lossy audio compression codecs that are used in DTV broadcasting, in almost every DVD and some Blu-ray discs. Appearing in the mid-90's, they replaced the analog Dolby Surround. They digitally separately and independently encode each channel using a perceptive method of selectively skipping data considered to be the least significant or masked by other sounds.

Dolby ProLogic IIx and IIz

This is in part the surround sound decoding mode (works on analog Dolby Surround encoded in two-channel soundtracks, the mode of volumetric expansion of any 2-channel source.It includes options for music, movies, games and rarely used emulations of the original Dolby ProLogic .Music mode DPLII is reliable Way to connect the two-channel source to the 5.1 system while maintaining the original stereo effect, but many will not replace the pure stereo.The 7.1-channel version (with the surround back) is Dolby ProLogic IIx, capable of outputting From 5.1 7.1. Its 9.1-channel version (with rear and high-altitude signals) was named Dolby ProLogic IIz.

Circle Surround, DTS Neo: 6, Neural Surround are competitors of the DPLII family. They extend the stereo to the surround sound using a variety of approaches.

Universal DSP modes

"Hall", "stadium", etc. are not of great value to most users and, with careless use, can be misleading. These modes rarely add genuine realism and can significantly reduce the sound quality of the audio system.

The main amplifier: 7.1 or 5.1?

Despite the distribution of additional surround channels, there is no need to use acoustics connection to the receiver according to the 7.1 scheme. You can simply disable the last two in the control menu and enjoy the additional dynamics of the other five. In some models, it is possible to rearrange the rear channel to amplify the front left and right speakers or to power the second zone.

Deceptive technical specifications

The specifications of the receivers are full of unreliable information. They are misleading when the published figures relate to only one or two channels, which looks better than the general situation. When comparing characteristics, one should search for the phrase "all channels". In addition, to determine the characteristics of the system, either the entire frequency range, or only 1 kHz, can be used. The duration of the test signal also has a large effect on the output power. The most difficult test today is the continuous supply of tones. Many manufacturers claim that the audio material does not contain continuous tones on all channels at the same time, so they sometimes use signals that last several milliseconds as a more realistic test. Unfortunately, there are many versions of such measurements, often called peak or dynamic power, which makes comparisons pointless. Small differences in the total harmonic distortion (THD) may be inaudible. And although manufacturers like to advertise this characteristic, most products on the market are doing well in this regard. The best advice is to get acquainted with the test results, which allow to determine what real power the receiver-acoustics kit has.

What power is needed?

In order for the receiver for the speaker system to match the speakers, you should review their specifications and find out the recommended amplifier power and nominal resistance. Speakers with an impedance of 6 ohms or less represent a more complex load than 8 ohms, since they require more current. This means that the AV receiver will be warming up more. The number of watts for a 4 ohm speaker is almost always higher than that of an 8 ohm, but the actual rated load of the speakers may not correspond to 4 ohms, no matter what specifications they are sold with. It must be remembered that the resistance varies with frequency and the nominal value indicated on the dynamics is largely silent. Amplifiers and receivers must provide the desired volume without distortion of sound or overload. It is necessary to take into account the size of the room, the distance to the speaker system and the sensitivity of the speakers. It is here that the THX certification, speaker manufacturer's recommendations and a reliable seller can be of great help. If you use 5 or more powerful speakers, you may need a better signal source than the one in the receiver. Probably, you need a good multi-channel amplifier.

Cross-conversion to HDMI

Many new receivers today allow you to convert all input signals to output them via HDMI, to connect only one cable to the display. This, of course, is desirable convenience, but its performance can be questionable. Some devices do this better than others, and the small print in the operating instructions of the THX-certified AV receivers often says that such a conversion is not recommended.

HDMI Connector: Key Interface

HDMI is the most versatile interface in modern home theater systems. If the AVR and the signal sources support it, then this can greatly simplify their connection.

When this standard only appeared, there were problems with component compatibility. But at their coordination the new receivers with HDMI win for two reasons. First, HDMI is a carrier of both audio and video, which reduces the overall confusion of cables. Secondly, many receivers direct all incoming signals to one output for a simple single-cable connection to the display. The HDMI 1.4 interface includes support for 3D, Ethernet, audio return channel and micro-connector.

Acoustic Receiver with HDMI 1.3 (or higher) is capable of processing high-resolution multi-channel PCM and allows decoding of lossless codecs. This standard is necessary for working with Blu-ray players. The HDMI 1.3 interface supports surround codecs as native streams. Older versions of the standard are capable of transferring some of them, but only 1.3 and higher give the opportunity to work with the majority, including DTS-HD Master Audio and Dolby TrueHD.

PCM via HDMI

Why is it important that the receiver for the speaker system can handle multi-channel, high-resolution PCM data via HDMI ports? First, because many Blu-ray discs offer multi-channel soundtracks in PCM format. Secondly, because many movies on Blu-ray players can convert Dolby TrueHD and DTS-HD Master Audio to uncompressed audio format for output over HDMI. Audio lossless can be obtained even if the AVR does not provide decoding of new codecs. In addition, it allows the player to add additional audio tracks.

Obsolete ports

Component video, like HDMI, is a form of HDTV connection. Serves only to transfer high quality analog video. If the AV receiver has only one HDMI output, this connection will allow you to connect a second monitor or solve compatibility problems. It is a connector of red, green and blue, which is on old TVs and DVD-players.

S-Video is an analog video connector in which the brightness and color signals are separated to avoid cross-color distortion. It was important before the appearance of HD, but today it is not necessary. S-video does not support high definition and in modern receivers starts to disappear.

Composite video uses a yellow connector, and it also does not support high definition. Composite and S-video is used in Laserdisc players, VCRs, analog cable TV sets and other antediluvian sources of signal. It is better to get rid of such equipment as quickly as possible.

Digital Coaxial and Optical Connectors

After HDMI, the next best choice is a digital connection using a coaxial or optical cable. There are different opinions about which one is better, but they are approximately equivalent. Coaxial and optical digital outputs are available on DVD and CD-players of CDs and in various set-top boxes. However, neither coaxial nor optical digital connections are compatible with the next generation of high-definition audio. However, they are capable of transmitting signals from the Dolby Digital and DTS standards.

Analog input and output

The number of sources with analog connectors of 7.1 or 5.1 systems includes Blu-ray players, SACD, DVD-Audio and very ancient DVD-players. They can bypass the bass control of the receiver and other settings, so you must use HDMI wherever possible.

Preamplifier outputs can be useful if you need to update the audio system and use the home receiver as a surround sound processor, along with a higher power amplifier for all or some channels. This also includes the connection of a subwoofer.

Cassette racks and other sources of analog signals may require connectors for stereo. The player requires a special input, otherwise it will be necessary to connect an external phono stage.

Multi-zone

Most models of receivers support multi-zone, i.e., capable of serving more than one room and several input sources. Multi-zone video is usually implemented as a composite or S-video standard resolution. Multi-zone audio is usually represented by analog stereo. Multi-zone is more focused on convenience than on high quality. Some devices also have a second remote control.

The Yamaha RX AV receiver, for example, has an intelligent gain distribution system , depending on the currently selected functions. For example, if the second zone is disabled, all 7.1 channels will be used in the main zone. When you turn on the second zone, the power of the two rear speakers will be directed to its two speakers, and the main one will remain with the 5.1 system. This eliminates the need to manually switch the cables on the rear panel of the receiver.

Ethernet

A receiver with acoustics can be connected to the router via an Ethernet cable to gain access to Internet radio, music, photos and video from a PC. Some network connections are certified by the digital network alliance for the DLNA home, and others are Windows. And they can do without licenses. If the music library is recorded on the hard disk, then such a connection becomes simply necessary. In addition, you need to regularly update the firmware, and Ethernet connectors allow you to do it online, which is better than other methods. Of course, Wi-Fi connection can be even more convenient, but for streaming multimedia it is much less reliable.

Additional interfaces

  • Most AV receivers have a dock for connecting iPod. You can purchase a universal docking station that connects to any analog input. Some receivers provide a direct connection.
  • The Yamaha RX AV receiver supports the AirPlay system, which allows wireless reception of streaming music from iPod, iPhone or iPad, as well as iTunes on a Mac or PC. This allows you to listen to music from mobile devices or home theater. In addition, you can view metadata such as the name of the song, artist, and album art.
  • USB is useful for connecting hard disk drives or flash memory. Also available are Bluetooth receivers for loudspeakers.
  • Additional ports include an infrared receiver connector that allows you to control the receiver when it is hidden in the cabinet.
  • The 12-volt trigger activates other devices, such as projectors, motorized screens and curtains.
  • RS-232 is used to replace software or connect third-party control systems.

Remote control

Another problem is remote management. If you do not plan to purchase a universal remote, you need to have something with buttons, clearly distinguishable in shape and color. Many consoles can be trained or have programmed instruction libraries. They can control other devices, such as HDTV and disc players. Also, if watching movies is done in a darkened room, the remote control, capable of switching on the light, will be a godsend.

A good receiver will become a source of constant satisfaction for many years.

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