Tuner bands
Radio bands accepted by the music centre tuner. To date, the most common support for such ranges:
— FM. Part of the ultra-short wave (VHF) band between 87.5 MHz and 108 MHz. It uses frequency modulation, which allows you to broadcast music in stereo with a fairly high sound quality, as well as transmit RDS signals (see RDS). At the moment, most music radio stations in the CIS broadcast in this range, as a result of which FM is supported in the vast majority of audio systems. The disadvantage of this option is the limited reception area — a maximum of several tens of kilometers from the transmitter — so FM broadcasts can usually be listened to within the same city and surrounding areas.
— AM (from the English amplitude modulation — amplitude modulation) — broadcasting using amplitude modulation. Usually this term means broadcasting on medium waves in the range of 520-1610 kHz; most consumer AM receivers are designed for these same frequencies. The reception range of AM stations can be hundreds of kilometers, but the sound quality is lower than on FM, so this format is broadcast mainly by “talk” and news radio stations.
— VHF. In this case, the sub-band 65.9-74 MHz is meant, using the so-called OIRT modulation. In this format, VHF broadcasting was originally conducted in the countries of the Soviet Union and Eastern Europe, but at the moment it is not very popular due to the development of FM. VHF is technically similar to FM (see above), the...main differences are the occupied frequency band and the inability to transmit RDS signals in VHF (see RDS).
— DAB+. DAB is an abbreviation for Digital Audio Broadcasting, i.e. "digital broadcasting"; and "+" means an improved version of this standard. Formally, DAB + is not only a range, but also a signal transmission format: unlike all the options described above, it, as the name implies, is digital. This gives a number of advantages over traditional transmitters — in particular, a greater range with less power and high quality of the broadcast sound. In addition, this sound is practically not subject to distortion: weak interference does not affect its quality, and when the transmitter power is critically reduced, the signal is not distorted, but disappears entirely. The latter, however, can be written down as disadvantages; but the really significant drawback of this option is perhaps its low prevalence (so far) in the CIS countries. Technically, such broadcasting can be carried out in any band above 30 MHz, but in fact several options are used (depending on the country) related to the VHF band. Note that DAB+ tuners are capable of receiving original DAB radio broadcasts, but not vice versa.
Tuner memory
The number of radio stations that can be stored in the tuner's memory.
By itself, the memory greatly simplifies the work with the tuner. Instead of having to manually search for your favorite stations each time, it is enough to “remember” them and in the future simply select the desired wave from the list in the receiver’s memory. The number of memory cells in modern audio systems can reach several tens; this will be especially useful for residents of metropolitan areas, where there are many stations on the air, as well as for those who often have to travel and tune
the receiver to local frequencies.
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.
Power per channel
Nominal sound power (see "System power") on each of the main channels of the audio system. This indicator is most often indicated in models with a subwoofer (see "Number of channels"); knowing it, you can estimate the power distribution between the main speakers and the subwoofer.
Impedance
The term "impedance" refers to the resistance of a speaker system to alternating current. Note that in the case of audio systems, this parameter plays a secondary role: it is important for selecting acoustics for an amplifier, and here both of these components are in most cases optimally matched by the manufacturer to each other. Therefore, in fact, information about the impedance can be useful only when looking for speakers to replace the complete ones: it is highly desirable that the new acoustics have the same impedance as the standard ones.
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).
Passive emitter
A passive radiator can be simply described as a low-frequency speaker that does not have its own reproducing system (coil with magnet). It is driven by pressure fluctuations created by active drivers and acts as a resonator to deliver deep, rich bass—especially useful for systems that do not include a subwoofer. At the same time, unlike phase inverters, passive radiators do not generate additional noise.
More features
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Omnidirectional sound. As the name implies, audio systems with this feature radiate sound evenly in all directions, covering a space of 360°. Thus, the device can be installed in the centre of the room and evenly “fill” it with sound, which will be clearly perceived at any point. On the other hand, an omnidirectional system usually sounds 1.0 (mono); the design may include various tricks to ensure surround sound, but these still in most cases do not reach full stereo.
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Voice assistant. Audio support for voice assistant. The most popular nowadays are such assistants:
However, other solutions are also possible. Anyway, it is worth noting that this is not about the function of the audio system itself, but about compatibility with smartphones, tablets and other gadgets that have their own voice assistants. Thus, to use the voice assistant, you will have to connect the audio system to an external device. On the other hand, the capabilities of such assistants are usually more extensive than those of built-in
voice control systems(see below); advanced features are often supported, such as natural speech recognition with complex queries (“Play the last album of the band … that I listened to”), weather fore
...cast, sports scores, etc. Of course, the specific set of supported commands and languages \u200b\u200bcan be different — depending on the voice assistant and its version.
— Voice control. A feature that is virtually mandatory for smart speakers (see "Intended Use") and hardly found in other types of audio systems. As the name implies, this control allows you to control the device using voice commands. It differs from the voice assistant (see the relevant paragraph) in that in this case we are talking about the simplest commands related to the main functionality of the audio system — for example, "Stop", "Continue", "Next track", etc. It is worth having in mind that voice control is almost guaranteed to support English, but the ability to recognize other languages should be specified separately.
— Smartphone control. The ability to control the audio system from a smartphone, tablet or other gadget with a special application installed on it. Usually, the connection is made via Wi-Fi (see "Interfaces"). The convenience of this function lies not only in the fact that you can control the system from a distance — the application is often more convenient and provides more options than the controls on the radio itself.
— Multiroom support. Device support for Multiroom technology. This technology allows you to create a single wireless network in the house from several speakers located in different rooms, and simultaneously play music in all these rooms. The specific features of such networks in different models may be different, they should be specified separately. So, some devices use a Bluetooth connection, others use Wi-Fi (directly or via a local network). In some cases, the control speaker broadcasts sound to all the others, and the same music plays throughout the house, in others, the speakers are “equal”, and different tracks can be turned on simultaneously in different rooms. Some audio systems require an external sound source (smartphone, tablet, etc.), others are capable of playing the role of a player themselves, including for streaming Internet services.
— Synchronization of speakers. The model supports the ability to synchronize the operation of several speakers connected to one signal source. This solution allows you to realize truly stereo sound, improve the quality and power of sound reproduction, as well as expand the stereo panorama. The only thing is that both speakers must support the appropriate connection type. Different brands may have their own speaker interconnection technologies (JBL Connect, JBL PartyBoost, Sony Party Chain), or maybe a universal TWS.
— Karaoke. A popular entertainment that allows users to sing their favorite songs to the backing track (musical accompaniment with the original vocals cut out) — in such a way that the vocals superimposed on the backing track are played through the acoustics of the audio system. This feature requires at least one microphone input.
— Karaoke Mix. An extended version of karaoke (see above), which provides various additional features — for example, performance evaluation in points, singing competitions, etc. Usually, it allows you to connect two microphones already.
— Internet radio. Ability to listen to Internet radio stations on the audio system. In general, such broadcasting is similar to conventional broadcasting, however, it is carried out not through the radio, but through the World Wide Web, which provides some additional features. So, Internet broadcasting has no restrictions on the range and ranges, allows you to listen to programs from any country and in any language; and the list of broadcasters is extremely extensive, among them there are both traditional radio stations duplicating their programs on the Internet, and specific, purely network projects. The presence of this function assumes support for at least one network interface — Wi-Fi or LAN (see "Interfaces").
— Recording to a USB drive. The ability of the audio system to record to an external USB device — for example, a USB flash drive. In this way, you can record your favorite radio programs from a conventional tuner or Internet station (see above), copy music from optical discs, etc.; Specific USB recording capabilities vary by audio system model.
— Clock. Ordinary clock — a device for displaying time, most often in the form of numbers on the display. Sometimes these hours are the most convenient. In addition, this function is necessary for some other features — primarily the alarm clock (see below).
— Alarm. A classic alarm clock that sounds at a set time. It can be useful not only for wake-up calls, but also in other cases when you need to warn the user about the arrival of a certain time. A feature of this function in audio systems is that the inclusion of a specific radio station or musical composition can be used as a signal.
— Shutdown timer. A feature that allows the audio system to turn off automatically after a user-defined time. Thanks to the timer, you can, for example, turn on relaxing music to fall asleep and fall asleep peacefully — the audio system will turn off on its own.
— Nightlight. The presence in the audio system of its own built-in lamp of low power, which allows it to be used as a night lamp. A night light can be useful for both young children and adults who are uncomfortable falling asleep in complete darkness; in addition, it can come in handy in situations where you have to get up in the middle of the night or early in the morning, before sunrise — at least with the light from the nightlight, it's easier to get to the main switch.
