Radio Data System (RDS)
Tuner support for Radio Data System technology. This technology is used mainly in the FM band; it allows, in addition to the sound signal, to transmit additional textual information by radio — for example, the names of broadcast compositions, announcements, advertising messages, etc. For RDS-enabled audio systems, this information is shown on the display.
Hi-Res Audio
The speaker supports high-resolution audio
Hi-Res Audio. The corresponding format is designed to provide sound close to that recorded in the studio. Hi-Res Audio refers to a digital signal with parameters starting from 96 kHz/24 bits, and for analogue equipment there is a requirement for an extended frequency response - from 40 kHz. Audio tracks in this format sound as close as possible to the original ideas of the authors of the compositions. The Hi-Res license marks premium solutions for avid audiophiles.
Number of bands
The number of distinct frequency ranges (bands) into which sound is divided when played through the acoustics of an audio system. For each such band, a separate speaker is provided, and sometimes several.
The simplest option provides 1 lane; it is very popular in modern audio systems, because. requires a minimum number of speakers, and the sound quality can be quite good. More advanced options provide 2-3 bands (low and high frequencies, or bass, treble and medium), and in high-end models, the number of bands can be up to five. Note that, in addition to integers, models are also produced with a fractional number of stripes — for example, 2.5 or 3.5. This marking indicates the presence in the design of a speaker responsible for two bands at once: for example, model 2.5 has separate speakers for bass and treble plus a combined bass + midrange (similar in design to bass, but also loaded with mid frequencies).
Anyway, the abundance of bands, usually, indicates a high class of acoustics: the more separate frequency ranges, the narrower the specialization of each speaker, the more accurately it is able to reproduce its part of the signal, and the more complex the system is.
Frequency range
The total frequency range reproduced by the acoustics of an audio system. Measured from the lower threshold of the lowest frequency speaker to the upper threshold of the highest frequency: for example, in a 2.1 system with main speakers at 100 – 22000 Hz and a subwoofer at 20 – 150 Hz, the total value will be 20 – 22000 Hz.
In general, the wider the frequency range, the fuller the reproduced sound will be, the less low and high frequencies will be lost due to insufficient acoustic capabilities. On the other hand, do not forget that the actual sound quality also depends on a number of other parameters — primarily the frequency response. In addition, human audible frequencies range from 16 Hz to 22 kHz; deviations from these values are very small, and the upper limit also decreases with age. Therefore, from a practical point of view, it does not make sense to provide too large a frequency range; and impressive performances like 10 – 50000 Hz, found in top-class models, are usually more of a kind of "side effect" of high-quality speakers (and at the same time — a marketing ploy) than a really significant moment.
Phase inverter
The phase inverter is a tube installed in the column housing and having an outlet to the surrounding space. The length of the tube is chosen so that a signal comes out of the outlet, inverted in phase relative to the signal from the front of the diffuser. This enhances the sound pressure and improves the sound of the speakers, including at low frequencies. Note that such audio systems should be placed at a certain distance from walls, furniture, etc. — otherwise, a hum may occur due to the movement of air through the phase inverter tube.
A similar function in some models is performed by a passive radiator (see below).
Bass Boost
Bass boost function for powerful and rich bass. Often implemented as a single button, with which you can actually "turn the bass on and off." This is more convenient than adjusting the low frequencies using the equalizer; in addition, various special technologies can be used to enhance the bass.
Inputs
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RCA. The RCA interface uses coaxial cables with characteristic tulip plugs and corresponding connectors. It can be used to transmit different types of data, but in this case it is meant to connect an audio signal from a preamplifier in analog format, one audio channel per connector. RCA is widely used in modern audio equipment, but its resistance to interference is very modest.
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Mini-Jack(3.5 mm). Standard connector for most modern portable audio equipment. In audio systems, it is mainly used to connect such equipment — primarily pocket media players. It uses analog signal transmission, but its resistance to interference, like that of RCA, is low, and the quality may be even lower due to the fact that both stereo sound channels are transmitted via one cable.
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Coaxial S/P-DIF. An electrical variation of the S/P-DIF standard that uses a coaxial cable with a tulip connector to transmit the signal. This interface should not be confused with the analog RCA described above — despite the identity of the connectors, these standards are fundamentally different: “coaxial” operates in digital format and allows for the transmission of even multi-channel sound over a single cable. Compared to optical S/P-DIF, this interface is less resistant to interference, but more reliable, since the electrical cables are not as delicate.
— Optical. One of the varie
...ties of the S/P-DIF standard — along with the coaxial one described above. In this case, the signal is transmitted via a TOSLINK fiber-optic cable. The main advantage of this interface is its complete insensitivity to electrical interference, while its capabilities are sufficient even for working with multi-channel sound. Among the disadvantages, it is worth noting the high price of connecting cables, as well as the need for careful handling of them.
— For microphone. Input for connecting a microphone to an audio system; can use different types of connectors (3.5 mm mini-Jack, 6.35 mm Jack, etc.). This function is mandatory for models with karaoke (see "Additional"), but can also be used for other purposes.
— Instrumental. Connectors used to connect musical instruments (acoustic or bass guitars, keyboards, etc.). Most often, they are made in the form of 6.35 mm Jack sockets. The audio signal from the pickups has its own specifics, so the instrument input is usually characterized by a higher input signal level and special impedance matching to ensure optimal sound quality.USB for charging gadgets
The ability to use the audio system to charge devices connected to it – pocket audio players, mobile phones, etc. For this usually a
USB port is used (microUSB or USB-C in modern models); some models are able to play music from an external gadget right in the process of charging.