DAC frequency
A digital-to-analogue converter (DAC) is an indispensable element of any system designed to reproduce digital sound. The DAC is an electronic module that translates sound information into pulses that are sent to the speakers. The technical features of such a conversion are such that the higher the sampling frequency, the better the signal at the output of the DAC, the less it is distorted during conversion. The most popular option in receivers today is 192 kHz — it corresponds to a very high sound quality (DVD-Audio) and at the same time avoids unnecessary increase in the cost of devices.
Audio DAC
Another indicator that determines the overall quality of the digital-to-analogue audio converter. For details on the converter, see "Audio DAC Sampling Rate"; here we note that the bit depth is standardly expressed in bits, and the higher it is, the more accurately the signal at the output of the DAC corresponds to the original signal and the less distortion is introduced into it. Today, it is believed that a 16-bit indicator provides quite acceptable signal quality, and 24-bit DACs are suitable even for premium-level equipment.
eARC
The audio receiver
supports eARC, an enhanced version of the Audio Return Channel (ARC) used with an HDMI connection (see below).
By itself, the audio return channel allows you to "swap" the HDMI output of the AV receiver and the HDMI input of the TV or other external device — thus, this device turns into an audio signal source, and the receiver starts to work as a receiver. Such functionality is designed mainly for those cases when the TV receives a signal not from the receiver, but from another source (built-in tuner, media player, flash drive, etc.), however, the soundtrack must be output to external speakers through the receiver. Without ARC, you would have to use an additional connection (for example, via an optical interface), while the audio return channel eliminates the need for extra wires: the same HDMI cable is used both for transmitting video / audio from the receiver to the TV and for transmitting audio from TV to receiver. Also, the advantages of ARC over traditional audio interfaces are higher bandwidth, as well as the ability to use the CEC function (control of connected devices from one remote control).
Specifically, eARC was introduced simultaneously with the HDMI 2.1 standard and received a number of improvements compared to conventional ARC. Here are the main ones:
— Up to 40x more bandwidth, allowing uncompressed 5.1 and 7.1 surround sound, HD audio and Dolby Atmos and DTS:X "object-orie
...nted" multi-channel codecs (see Decoders).
— Technology Lip Sync Correct, eliminating desynchronization between video and sound.
— Proprietary protocol to automatically detect audio formats supported by both connected devices and select the best option.
Of course, in order to use eARC, both the receiver and the TV it is connected to must support it.Power per channel
the
maximum sound power that can be delivered by the power amplifier (if the receiver has one, see "Type") per speaker channel. It is worth noting here that in this case it is customary to indicate the so-called RMS (Rated Maximum Sinusoidal), or rated power. Rated is considered the highest power that the amplifier is guaranteed to be able to produce without interruption for an hour without any failures or breakdowns. Short-term jumps in the signal level can significantly exceed this value, but the main indicator is still the rated power.
The power of the amplifier largely determines the sound volume of the speaker system connected to the device. In fact, the loudness also depends on the characteristics of the speakers — sensitivity, impedance, etc.; however, other things being equal, the same acoustics on a more powerful amplifier will sound louder. In addition, this parameter also affects the compatibility of the speakers and the amplifier — it is believed that the difference in the nominal powers of these components should not exceed 10-15% (and ideally, the powers should generally match). And since different rooms require speakers of different power, this also affects the choice of amplifier for a particular environment; specific recommendations on the ratio of room characteristics and acoustic power can be found in special sources.
Also note that if the amplifier can operate with a load of different resistance (see
..."Permissible acoustic impedance"), then for different options the power per channel will be different — the lower the resistance, the higher the power. In the characteristics, in this case, the maximum value of this parameter is usually indicated — that is, the power at the minimum allowable resistance.Decoders
A decoder can be broadly described as a standard in which digital audio (often multi-channel) is recorded. For normal playback of such sound, it is necessary that the corresponding decoder is supported by the device. The first signs of multi-channel decoding were
Dolby Digital and
DTS, gradually improving and introducing new features. The final stage for 2020 is Dolby Atmos and
DTS X decoders. And the intermediate ones were
Dolby TrueHD,
Dolby Pro Logic II,
DTS-HD,
DTS ES,
DTS Neural: X,
DTS Neo (6, X).
Dolby Atmos. A decoder that does not use a rigid distribution of sound across channels, but the processing of audio objects, due to which it can be used with almost any number of channels on a reproducing system — the sound will be divided between channels so that each audio object is heard as close as possible to its proper place. When using Dolby Atmos, in-ceiling speakers (or speakers facing the ceiling) are highly desirable. However, in extreme cases, you can do without them.
— DTS X . An analogue of the Dolby Atmos described above, when the sound is distributed not through individual channels, but through audio objects. The
...digital signal contains information about where (according to the director's intention) the object audible to the user should be and how it should move, and the processor of the reproducing device processes this information and determines exactly how the sound should be distributed over the available channels in order to achieve the required localization. Thanks to this, DTS X is not tied to a specific number of audio channels — there can be as many as you like, the system will automatically divide the sound into them, achieving the desired sound. Also note that this decoder allows you to separately adjust the volume of dialogues.
— IMAX Enhanced. The IMAX Enhanced Mark of Conformity is awarded to equipment that meets the audio certification requirements of IMAX Corporation. Combined with DTS audio technology to deliver signature IMAX theater-like sound in the home. The most accurate reproduction of such audio is possible in systems with a large number of channels (5.1 or more). Note that for a fully immersive experience, IMAX Enhanced certification must also apply to video equipment for playing content (TV, projector, etc.).Component
The number of component inputs provided in the design of the receiver.
This interface (also known as YPbPr) is designed to transmit analogue video. Its name comes from the fact that the three main video components (brightness data and two colour difference channels) are carried over three separate cables. Accordingly, each individual component input is a set of three connectors. Usually, a built-in cable with RCA connectors (“tulip”) is used for connection, while the cables for component and composite (see below) interfaces are quite interchangeable.
The component interface stands out for its high signal transmission quality: splitting the video into three separate channels significantly reduces distortion compared to the same composite format, and the bandwidth is comparable to the above-described HDMI and allows you to work even with HD video. However, a component connection does not provide audio, and you will need to use a separate cable for this purpose.
As for the quantity, the presence of several inputs allows you to connect several signal sources to the receiver at once with the corresponding outputs and switch between them through software settings without fiddling with switching cables.
RCA
The number of analogue stereo RCA outputs provided in the design of the AV receiver.
By itself, the
RCA connector (colloquially — "tulip") can be used in different interfaces. However, in this particular case, we are talking about a linear audio output that is responsible for an analogue audio signal. RCA is the most popular connector used in modern audio equipment for such outputs. In this case, we can talk about both standard outputs for connecting speakers, and about REC connectors designed to connect a recording device to the receiver and differ in a constant signal level. (however, there is rarely more than one such output). In addition, preamplifier outputs are also taken into account here.
Note that connectors of this type are usually counted in pairs; in other words, one output consists of two RCA connectors. This is due to the fact that in this case only one channel of analogue audio can be transmitted over one wire; accordingly, two RCA jacks are required for stereo transmission.
Several RCA outputs allow you to connect several sets of acoustics to the receiver at the same time — for example, to broadcast sound in several rooms at once or to record sound in parallel with listening to it.
Composite
The number of
composite outputs provided in the design of the receiver.
Note that in this case we do not mean a full-sized composite interface that uses three jacks (video and two channels of stereo sound), but only one connector — video (sound can be output through standard RCA connectors). The video output also uses an RCA connector, usually a distinctive yellow colour.
Due to the fact that all image data is transmitted over a single cable, the composite interface is somewhat inferior to the component (see above) in terms of video quality, and the bandwidth allows you to work only with a standard definition signal (not HD); and there is no talk of volumetric sound. On the other hand, this connection method has long been used in video technology and can be useful for connecting outdated devices (such as VHS VCRs).
The presence of several outputs allows you to connect several signal receivers at the same time and select a playback device without reconnecting cables — by changing the settings of the receiver. And in models that support Multi Zone (see above), you can simultaneously broadcast different signals to different receivers.
Trigger output
The number of trigger outputs provided in the design of the receiver.
The trigger output is used to automatically turn on other audio system components connected to the receiver. When the receiver itself is turned on, a control signal is sent to this output, which “wakes up” the connected device (for example, an external amplifier) and relieves you of the need to turn it on manually. Of course, to use this function, such a device must be equipped with a trigger input.
See "HDMI" above for the meaning of the number of any outputs.