Power per channel (8Ω)
The nominal sound power output by the audio receiver per channel when operating with a load having a dynamic resistance (impedance) of 8 ohms. In our catalog, this parameter is indicated for the mode when both channels of the receiver work under load; when working on one channel, the rated power may be slightly higher, but this mode cannot be called standard.
Rated power can be simply described as the highest average output signal power at which the amplifier is able to operate stably for a long time (at least an hour) without negative consequences. These are average figures, because in fact, an audio signal is, by definition, unstable, and individual jumps in its level can significantly exceed the average value. However, the key parameter is still the nominal (average) power — it is on it that the overall sound volume directly depends.
This indicator also determines which speakers can be connected to the device: their rated power should not be lower than that of the receiver.
According to the laws of electrodynamics, with different dynamic load resistance, the output power of the amplifier will also be different. In modern speakers, values of 8, 6, 4 and 2 ohms are standard; the latter option, however, is rare, therefore, in audio receivers, the power for it, usually, is not indicated at all. As for the specific values for 8 ohms, the indicator
up to 50 W is considered relatively low,
50 – 100 W is average, and with
more than 100 W we can talk about high power.
Permissible speaker impedance (Ω)
The lowest speaker impedance that the audio receiver can handle normally.
The nominal impedance of the speakers, also referred to as the term "impedance", is one of the key parameters in the selection of audio system components: for normal operation, it is necessary that the speaker impedance match the characteristics of the amplifier. If the speaker impedance is greater, the sound volume will decrease significantly, if it is less, distortion will appear in it, and in the worst case, even overloads and breakdowns are possible. Therefore, in the characteristics of receivers, it is usually the minimum resistance that is indicated — after all, connecting a load of too low impedance is fraught with more serious consequences than too high.
Audio formats support
Audio file formats that the receiver is capable of working with. Among those, there may be lossy compressed (MP3, WMA, etc.), lossless compressed
Lossless(FLAC, APE, etc.) and
Uncompressed uncompressed formats (DSD, DXD, etc.).
In general, compression is used to reduce the volume of audio files. Lossy compression (the most common option) cuts off some of the audio frequencies (mainly those that are poorly perceived by the ear), making such files take up the least amount of space. Lossless compression preserves all original frequencies; this format is preferred by many lovers of high-quality sound, however, such files take up a lot of space, and the difference between normal compression and lossless compression becomes clearly noticeable only on high-quality equipment. Uncompressed formats, in turn, are intended primarily for professional audio work; their full reproduction requires Hi-End audio equipment, and the volumes of such materials are very large. However, these standards are quite popular among sophisticated audiophiles.
Separately, it is worth touching on
the uncompressed DSD format. This standard and its direct derivatives DSF and DFF use coding using the so-called pulse density modulation. It is considered more advanced than traditional pulse-frequency modulation, and allows you to achieve more accurate sound, a higher signal-to-noise ratio
...and less interference with a relatively simple element base.Outputs
Outputs provided in the design of the device. Note that for receivers (see "Type") the presence of outputs for passive acoustics is mandatory by definition, and the players, on the contrary, do not have such outputs. Therefore, the presence / absence of such connectors is not separately indicated.
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Preamplifier output (Pre-Amp). A preamplifier is an electronic unit designed to amplify an audio signal to line level. Accordingly, outputs of this type are actually line outputs for outputting sound to an external power amplifier, active acoustics, etc. For players (see "Type"), these are the main analogue audio outputs, and in receivers, Pre-amp outputs can be used in including for connecting equipment that works in parallel with passive speakers, which provides additional features for expanding the audio system. Most often, this interface uses paired RCA connectors (“tulips”), one for each stereo sound channel; less often — balanced XLR, also paired, for more details see "Inputs".
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To the subwoofer. A separate output for connecting a subwoofer — a specialized speaker designed for low frequencies. Usually uses an RCA ("tulip") interface, but there may be other options. Anyway, this output receives the signal from the crossover, which "cuts" the mids and highs, leaving the bass with which the speaker works. This simplifies the connection and eliminates the need to look for external equipm
...ent for the normal operation of the subwoofer — for example, the same crossover (although an external amplifier may be needed for passive "subwoofers").
— Coaxial S/P-DIF. A kind of S/PDIF digital audio interface that uses an electrical coaxial cable with RCA connectors (“tulip”) for connection. Such a cable, unlike optical, is subject to electromagnetic interference to a certain extent, but is more reliable and does not require special care in handling. And the connection bandwidth is enough to transmit multi-channel audio up to 7.1. Note that, despite the identity of the connectors, the coaxial digital interface is not compatible with analogue RCA; and even cables for S / P-DIF are recommended to use specialized ones.
— Optical. A variation of the S/PDIF digital audio interface that uses a TOSLINK fiber optic cable connection. In terms of throughput, it is completely similar to the coaxial interface, but it compares favorably with its complete insensitivity to electromagnetic interference. On the other hand, due to their design, optical cables are sensitive to sharp bends and mechanical stress — for example, accidentally stepping on such a cable can damage it.
— Balanced digital (AES/EBU). An interface used primarily in professional audio equipment. It can use different types of connectors, but is most often implemented via XLR. For more information about this connector and the principle of balanced connection, see “Inputs — XLR (balanced)”, however, these two interfaces should not be confused: AES / EBU works with a digital signal transmitted over a single cable, regardless of the number of channels.
— Composite (video). This output is usually provided in models equipped with a video input of the same standard. For composite connectors in general, see "Inputs". Here also note that the role of composite audio outputs in this case is played by the main outputs of the receiver, to which acoustics are connected — in other words, the sound accompanying the video is output directly to the standard speakers of the audio system.
— BNC. Bayonet type connector used to connect coaxial cable. Theoretically, it can be used for various purposes, but in fact it is most often used similarly to coaxial S / P-DIF (see the relevant paragraph), for digital analogue audio. BNC connectors are more reliable in connection due to the bayonet lock; there is also a version with a threaded fixation.
— Trigger. 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 amplifier) and relieves you of the need to turn it on manually. Of course, to use this function, the external device must be equipped with a trigger input.
— Control output (IR). The control output allows you to use the receiver's built-in IR receiver to control other components in your audio system from the remote control, such as an amplifier in another room, out of range of the remote control. With this scheme of operation, the audio receiver actually plays the role of a remote sensor, receiving commands and transmitting them through the control output to another device. Note that the very presence of such inputs and outputs does not guarantee the compatibility of various devices, especially if they are produced by different manufacturers; Sharing details should be clarified in the official documentation.REC (to recorder)
The number of
outputs to the recording deviceprovided in the design of the audio receiver.
Technically, the REC output is most often a traditional line interface, with a pair of RCA connectors (for left and right stereo channels — that's why such outputs are counted in pairs). The main specificity of this interface (and the difference from "ordinary" line outputs) is that the signal level on it is unchanged — this simplifies the control of recording parameters on an external device.