Frequency range
The range of audio frequencies that the audio receiver can handle. The wider this range, the more complete the overall picture of the sound, the less likely it is that too high or low frequencies will be “cut off” by the output amplifier. However, note that the range of sound audible to a person is on average from 16 Hz to 20 kHz; There are some deviations from this norm, but they are small. At the same time, modern Hi-Fi and Hi-End technology can have a much wider range — most often it is a kind of "side effect" of high-end circuits. Some manufacturers may use this property for promotional purposes, but it does not carry practical value in itself.
Note that even within the audible range it does not always make sense to chase the maximum coverage. It is worth, for example, to take into account that the actually audible sound cannot be better than the speakers are capable of giving out; therefore, for a speaker system with a lower threshold of, say, 70 Hz, there is no need to specifically look for a receiver with this figure of 16 Hz. Also, do not forget that a wide frequency range in itself does not absolutely guarantee high sound quality — it is associated with a huge number of other factors.
Signal to noise ratio (RCA)
Signal-to-noise ratio when operating the audio receiver through the RCA line input (see below).
Any signal-to-noise ratio describes the ratio of the level of pure sound produced by the device to the level of extraneous noise that occurs during its operation. This parameter is the main indicator of the overall sound quality — and very clear, because. its measurement takes into account almost all the noise that affects the sound in normal operating conditions. A level
of up to 90 dB in modern receivers can be considered acceptable,
90 – 100 dB is not bad, and for advanced audiophile-class devices, a signal-to-noise ratio
of 100 dB or more is considered mandatory.
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.Streaming services
A set of
streaming services supported by the receiver.
Streaming (streaming) services are designed to broadcast content (in this case, mainly music) over the Internet. With such a broadcast, audio files are not saved on the receiver, but are played directly from the corresponding resource on the Internet; Nowadays, there are many such resources, varying in the range of music and access conditions. In any case, the main advantages of online streaming include a wide selection of content and almost instant access to the desired composition; Some services can also work like a radio, automatically selecting music according to the producer's preferences. Key resources include
Spotify,
TIDAL,
Qobuz,
Amazon Music.
RCA
The number of line inputs in the design of the audio receiver using the RCA interface are characteristic “tulip” connectors. This interface allows for an analogue connection to transmit only one channel of sound per connector, and audio receivers traditionally work with stereo sound. Therefore, it is customary to consider a pair of two RCA connectors (one for the left and right channels) as one output, and the calculation of the total number is carried out precisely by pairs, and not by individual sockets.
When connected to a line input, the signal goes through all the stages of processing provided in the device — for example, adjusting the balance or frequencies (see "Adjustments"). In this respect, this input differs from Main (see "Inputs"). The number of connectors determines how many signal sources can be simultaneously connected to the audio receiver. Accordingly, it is worth choosing a model according to the number of inputs, taking into account the expected number of such sources: after all, it is easier to connect them all and select through the remote control or control panel than to fiddle with reconnecting every time. As for the specific number of RCA inputs, most often it
does not exceed three, however, there are
exceptions.
Power consumption
The power consumed by the audio receiver during normal operation. Note that this parameter can be indicated in different ways: for example, some manufacturers measure it when the amplifier is operating at full power, while others measure it at 80% or 50% power. In addition, the power consumption of modern receivers is usually not so high as to put a serious strain on the power supply systems. Therefore, power consumption information usually plays a supporting role.
