Comparison Mystery MMK-755U vs Mystery MMK-702U

Radio ranges received by the tuner of the music center. Today, the most common ranges supported are:

— FM. Part of the ultra-short-wave (VHF) range from 87.5 MHz to 108 MHz. Uses frequency modulation, which allows you to broadcast music in stereo with 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 dozen kilometers from the transmitter - so FM broadcasts can usually be listened to within one city and its surrounding areas.

— AM (from English amplitude modulation) — radio broadcasting using amplitude modulation. Usually, this term refers to broadcasting on medium waves in the range of 520–1610 kHz; most consumer AM receivers are designed for these same frequencies. The range of AM stations can be hundreds of kilometers, but the sound quality is lower than on FM, so this format is mainly used for talk and news radio stations.

— DAB+. DAB is an abbreviation for Digital Audio Broadcasting, i.e. “digital radio 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 is, as the name suggests, digital. This provides a number of advantages over traditional transmitter...s — in particular, a greater range at lower power and high quality of the transmitted sound. In addition, this sound is practically not subject to distortion: weak interference does not affect its quality, and with a critical decrease in transmitter power, the signal is not distorted, but disappears completely. The latter, however, can be written down as a disadvantage; but the only truly significant disadvantage of this option is its low prevalence (so far) in the CIS countries. Technically, such broadcasting can be carried out in any range above 30 MHz, but in practice, several options are used (depending on the country), related to the VHF range. Please note that DAB+ tuners are capable of receiving original DAB radio broadcasts, but not vice versa.

The total sound power provided by the audio system at maximum volume, in other words, the total power of all the speakers provided by the device (including the subwoofer).

The higher the power, the louder the system will sound and the larger the area it can cover. On the other hand, high power significantly affects the price, dimensions, weight and power consumption of the device. In addition, when evaluating and comparing according to this indicator, it is worth considering some nuances. Firstly, some manufacturers go to the trick and give in the characteristics not the average, but the peak sound power; such numbers can be quite impressive, but they have very little to do with real loudness. So if it seems to you that the claimed power is too high, it's ok to clarify what exactly is meant in this case. Secondly, when comparing, it is worth considering the presence of a subwoofer — it plays an auxiliary role, but it can account for more than half of the total system power. Because of this, for equal total power, a device with a subwoofer may be quieter than a model without a subwoofer: for example, a 2.0 40W system will have 20W per main channel, while a 2.1 40W model may have 20W per subwoofer, and only 10 watts for the main speakers.

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.

The presence of an equalizer function in the audio system.

Equalizer allows you to change the timbre of the sound by adjusting the volume for individual frequency bands. The simplest version of this adjustment provides 2 bands (high and low frequencies), but most often there are more bands. Anyway, the equalizer can be useful both for fine-tuning the sound to your own preferences, and for compensating for the shortcomings of external or standard acoustics, connected headphones, etc. - for example, if the speakers "fail" certain frequency bands. In addition, many audio systems have a set of equalizer presets (presets), usually designed for different styles of music - "Classic", "Rock", "Pop", etc. You may also be able to create and edit your own presets.

- AirPlay. AirPlay technology was developed by Apple. It is based on Wi-Fi and is used to wirelessly broadcast content from Apple devices to external audio systems. Thus, this function is useful for tech who want to connect an iPhone or iPod touch to the audio system, but do not want to bother with wires; However, it is possible to connect other devices via AirPlay - for example, a PC with iTunes and a Wi-Fi module installed.

- AirPlay 2. The second generation of the AirPlay technology described above, introduced in 2018. Among the main innovations of this version is support for the multiroom format, that is, the simultaneous broadcast of several audio signals to different compatible devices installed in different places. In this way, you can, for example, turn on a radio broadcast of a news program in the living room, relaxing music in the bedroom, etc. In addition, AirPlay 2 received a number of other improvements - improved buffering, the ability to stream to stereo speakers, as well as support for voice control via Siri.

- Chromecast. Original name: Google Cast. Technology for broadcasting content to external devices, developed by Google. Allows you to transmit an audio signal from a PC or mobile device to the audio system; the broadcast is usually carried out via Wi-Fi, while the receiver and the signal source must be on the same Wi-Fi network (with t...he exception of Chromecast media players). Note that in signal sources (smartphones, tablets, PCs, etc.) Chromecast is implemented at the level of individual applications. For example, at the time of its creation, this feature was available, in particular, in the YouTube and Netflix applications for Android and iOS, as well as in the web versions of these applications for Chrome. Thanks to this format, this technology is extremely widespread these days, and the ability to connect a particular gadget to an audio system with Chromecast is usually limited to the ability to install appropriate applications on this gadget.

- DLNA. DLNA (Digital Living Network Alliance) is a standard that allows you to combine various types of home electronics and household appliances into a single network for content exchange and control. In the case of audio systems, DLNA can be used, for example, to play music from the disk of a computer connected to such a network, broadcast sound to a device installed in another room (for example, an amplifier), etc. Connecting to DLNA can be done either wired or wirelessly (using the Wi-Fi standard), and device compatibility does not depend on their manufacturers - the only condition is compliance with the DLNA standard.

- LAN. Standard interface for wired communication to local computer networks based on the RJ-45 connector. Its presence allows you to use various network functions, such as Internet radio (see "Advanced") or DLNA (see above). Compared to another network interface - Wi-Fi - LAN is less convenient due to the presence of wires, but is more reliable and provides a higher actual data transfer speed.

- Wi-Fi. The presence of a Wi-Fi wireless communication module in the audio system design. This technology is used both in computer networks and for directly connecting various devices to each other; its “range” is sufficient to work within residential premises, even through walls. In this case, Wi-Fi can be used to work with network functions such as Internet radio or DLNA(see above). Moreover, this option is more convenient than a wired LAN due to the absence of actual wires. In addition, support for this technology is a prerequisite for using the AirPlay and Chromecast functions (see above); and in some devices, Wi-Fi even allows you to connect smartphones, tablets and other gadgets as remote controls.

One of the most modern and fastest standards of this wireless communication technology is Wi-Fi 5. The 802.11ac version uses the 5 GHz band (less congested and more noise-resistant than 2.4 GHz), providing speeds of up to 1.69 Gbps per antenna and up to 6.77 Gbps with multiple antennas.

— Bluetooth. Direct wireless communication technology between various devices. One of the most popular ways to use Bluetooth in audio systems is to work with an audio signal, primarily broadcasting sound to wireless headphones or speakers; and some models also provide the ability to connect a smartphone, tablet or other device and use the audio system as an external Bluetooth speaker. However, it is worth considering that initially Bluetooth is noticeably inferior to a wired communication in terms of sound quality; however, in our time, this disadvantage is often compensated by the use of one or another version of the aptX codec(see below).
In addition, other options for using Bluetooth may be provided - for example, exchanging files between the built-in memory and the same smartphone, or remote control via an application. They are not mandatory for modern audio systems, but with the development of technology they are becoming increasingly widespread.

In modern audio systems, the Bluetooth v 5 standard is most often used. Its important innovation is the expansion of the capabilities of the BLE (Bluetooth Low Energy) mode: if necessary, the device can increase the range by reducing the speed, or speed up transmission at the cost of reducing the range. In addition, a number of improvements have been introduced regarding simultaneous work with multiple connected devices.

- aptX support. The audio system supports aptX, a codec designed to improve the quality of sound transmitted via Bluetooth. Accordingly, this function automatically means the presence of a built-in Bluetooth module (see above). The need to use special technologies is due to the fact that in the original Bluetooth format the audio signal is very highly compressed, which significantly affects the final sound quality. The aptX technology is designed to correct the situation: according to the creators, it provides sound purity “comparable to Audio CD (16-bit/44.1kHz)” and almost as good as a wired communication. This is often enough even for comfortable listening to lossless formats, not to mention MP3 and other popular compressed formats. Of course, to use aptX, the signal source must also support it.

- aptX HD support. Audio system support for the aptX HD codec - an improved and updated version of the aptX described above. This version claims sound purity comparable to Hi-Res audio materials (24-bit/48kHz); this allows you to comfortably listen not only to MP3, but also to lossless formats and even uncompressed audio materials. On the other hand, aptX HD support is quite expensive, and its advantages over the original aptX only become noticeable on very high-quality audio materials, for which consumer audio systems are rarely used. Therefore, this function is not particularly widespread.

- A.A.C. A codec used primarily in Apple portable devices to improve sound transmitted via Bluetooth. In this sense, it is similar to aptX (see the corresponding paragraphs), but is noticeably inferior to it in terms of capabilities: if the sound of aptX is compared with Audio CD, then AAC is at the level of an average quality MP3 file. However, for listening to the same MP3s, this is quite enough; the difference becomes noticeable only on more advanced formats.

-LDAC. Sony's proprietary Bluetooth codec. It surpasses even aptX HD in terms of bandwidth and potential sound quality, providing performance at the Hi-Res level of 24-bit/96kHz audio; there is even an opinion that this is the maximum quality that it makes sense to provide in wireless headphones - further improvement will simply be imperceptible to the human ear.

— Network streaming audio. The ability of the audio system to work with network streaming audio services such as Deezer, Spotify, Tidal, etc. Such services are designed to broadcast content (in this case, mainly music) over the Internet; in this case, the played files are not saved in the audio system, but are played directly from the corresponding resource on the World Wide Web. Nowadays, there are many streaming services that differ in the range of music and access conditions; The specific list of supported services should be clarified separately. However, in any case, the main advantages of online streaming include an extensive 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.

- Speakerphone. Possibility of using the device as a hands-free system for a mobile phone. In this mode, the audio system connects to the device, most often using Bluetooth (see above), and the voice of the subscriber on the other end of the line is output not to the phone, but to the speakers of the audio system. This is often more convenient than holding the phone to your ear; In addition, speakerphone is useful if several people need to participate in a conversation.

— NFC chip. NFC is a short-range wireless technology (about 10 cm). In audio systems, NFC is used primarily to facilitate communication via Wi-Fi or Bluetooth (see above). With this chip, you can simply bring an external NFC-compatible device to the audio system and confirm the communication - it's easier than manually adjusting settings.

— Omnidirectional sound. As the name suggests, audio systems with this feature emit sound evenly in all directions, covering a 360° space. Thus, the device can be installed in the center 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 in 1.0 format (mono); the design may include various tricks to ensure surround sound, but such systems still fall short of full-fledged stereo in most cases.

— Voice assistant. Support of the audio system of the voice assistant. The most popular assistants nowadays are:

• Google Assistant
• Apple Siri
• Amazon Alexa

However, other solutions can also be used. In any case, it is worth noting that we are not talking 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 functions are often supported, such as natural speech recognition with complex queries (“Play the latest album of the band ... that I listened to”), voicing the weather forecast, sports results, etc. Of course, the specific set of supported commands and languages may vary - depending on the voice assistant and its version.

— Voice control. A function that is practically mandatory for smart speakers (see “Purpose”) and is almost never found in other types of audio systems. As the name suggests, this control allows you to control the device using voice commands. It differs from the voice assistant (see the corresponding section) 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 keeping in mind that voice control almost certainly supports English, but the ability to recognize other languages should be clarified separately.

— Mobile application. The ability to control the audio system from a smartphone, tablet or other gadget with a special application installed on it. As a rule, the connection is via Wi-Fi (see "Interfaces"). The convenience of this function is not only that the system can be controlled remotely - the application is often more convenient and provides more options than the controls on the radio itself.

— Multiroom support. The device supports Multiroom technology. This technology allows you to create a single wireless network in your home from several speakers placed in different rooms, and simultaneously play music in all of these rooms. The specific features of such networks may be different in different models, they should be clarified separately. So, some devices use a Bluetooth connection, others - via 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 played 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.

— Karaoke.... A popular entertainment that allows users to sing their favorite songs to a backing track (musical accompaniment with the original vocals cut out) — so that the vocals superimposed on the backing track are reproduced through the acoustics of the audio system. This function requires at least one microphone input.

— Karaoke Mix. An extended version of karaoke (see above), providing various additional options — for example, assessment of performance skills in points, singing competitions, etc. As a rule, it allows you to connect two microphones.

— Internet radio. The ability to listen to Internet radio stations on the audio system. In general, such broadcasting is similar to conventional broadcasting, but it is carried out not via radio, but via the World Wide Web, which provides some additional opportunities. Thus, Internet broadcasting has no restrictions on range and range, 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 broadcasts 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 to operate the audio system in recording mode to an external USB device, such as a flash drive. This allows you to record your favorite radio programs from a regular tuner or Internet station (see above), copy music from optical discs, etc.; specific USB recording capabilities depend on the audio system model.

— Clock. A regular clock is a device for displaying time, most often in the form of numbers on a display. Sometimes it is precisely such a clock that turns out to be the most convenient. In addition, this function is necessary for some other features — primarily an alarm clock (see below).

— Alarm clock. A classic alarm clock that gives a signal at a set time. It can be useful not only for waking up, but also in other cases when it is necessary to warn the user about the onset of a certain time. The peculiarity of this function in audio systems is that the signal can be the switching on of a certain radio station or musical composition.

— 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.

— 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.

— 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.

— RCA. The RCA interface uses coaxial cables, with characteristic "tulip" plugs, and the corresponding connectors. It can be used to transfer different types of data, however, in this case, it means outputting an audio signal in analogue format, one channel of audio per connector. RCA is widely used in modern audio technology, but its resistance to interference is very limited.

— Mini-Jack (3.5 mm). One of the standard connectors in modern audio equipment, it is widely used in portable devices, as well as for connecting headphones. However, we note that in this case we mean the jack responsible for the line output — an interface for transmitting an audio signal in analogue format to an external device, such as an amplifier. The headphone jack is listed separately in our catalog, even if it belongs to the 3.5 mm mini-Jack standard; See below for details on headphone output.

— Coaxial S / P-DIF. An electrical version of the S / P-DIF standard, using a coaxial cable with a “tulip” connector for signal transmission. Do not confuse this interface with the analogue RCA described above — despite the identity of the connectors, these standards are fundamentally different: "coaxial" works in digital format and even multi-channel audio can be transmitted over a single cable. Compared to optical S/P-DIF, this interface is less resistant to interference, but more rel...iable because electrical cables are not as delicate.

— Optical. One of the varieties of the S / P-DIF standard is, 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 to work with multi-channel audio. Among the shortcomings, it is worth noting the high price of connecting cables, as well as the need for careful handling of them.

— Subwoofer. A separate output for connecting an external subwoofer — a specialized low-frequency speaker. The use of such a speaker allows you to significantly improve the sound of low frequencies, make the bass powerful and rich, which general-purpose speakers are not capable of. Note that such an output can also be useful in systems with a built-in subwoofer — external "subwoofers" are in most cases more powerful and provide more options for adjusting the sound.

— Headphones. Separate headphone output. Most often, a standard 3.5 mm mini-Jack or 6.35 Jack is used for this purpose, but there may be other options — for example, a manufacturer's proprietary connector. Anyway, headphones can come in handy in situations where you need to keep quiet — for example, if you want to listen to music at a late time when others are already sleeping — or vice versa, in noisy environments when ambient sounds drown out the speakers of the audio system.

— Composite. The full-size composite interface includes three connectors — one for video transmission and two for left and right stereo channels. However, in this case, a composite output usually means only a video connector (the standard acoustics of the audio system are responsible for the sound, it usually makes no sense to broadcast it to a TV). Anyway, this output allows you to connect the audio system not only to the latest, but also to frankly outdated TVs. Its disadvantages are poor image quality and incompatibility with HD.

— Component. Output for transmitting video signal in analogue format. Outwardly similar to the composite interface described above, because also uses three RCA cables; however, in this case, these cables carry three components of the video signal (hence the name). The component interface is considered the most advanced among the popular analogue video standards, it provides the highest image quality among them and is even capable of working with HD resolutions. Among the shortcomings, it is worth noting the impossibility of transmitting sound — this will require a separate connection.

— S video. Analogue interface for video transmission. In some way similar to the component described above, since it also provides separate wires for transmitting video signal components; however, in this case there are only two of these wires. This, on the one hand, allowed us to limit ourselves to one connector instead of several, on the other hand, it slightly reduced the quality of the “picture” and limited the bandwidth, so HD is out of the question with such a connection.

— SCART. Universal audio/video interface using a characteristic large 21-pin connector (20 pins plus a rim around the connector). For a long time it was the standard for European video equipment, but today it is considered obsolete due to its low bandwidth and significant dimensions. Note that SCART can work with signals of different formats, which allows the use of adapters — in particular, for connecting external devices via composite and component interfaces.

— HDMI. Universal digital interface that allows you to transfer HD-video and multi-channel audio over a single cable. It is practically a standard for modern video equipment, in particular, it is present in most TVs. In audio systems, this type of output is used in the same way as the coaxial S / P-DIF described above — that is, to output the audio signal in digital form.