Comparison Pioneer X-PM12 vs Pioneer X-HM51

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.

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.

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.

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).

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.

— RCA. The RCA interface uses coaxial cables with characteristic "tulip" plugs and corresponding connectors. It can be used to transfer different types of data, however, in this case, it means connecting the audio signal from the preamplifier 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). 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 analogue signal transmission, while the resistance to interference, like RCA, is not high, and the quality may even be lower due to the fact that both channels of stereo sound are transmitted over the same cable.

— 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 reliable because electrical cables are not as delicate.

— Optical. One of the va...rieties of the S / P-DIF standard is, along with the coaxial one described above. In this case, the signal is transmitted via a TOSLINK fibre 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.

— Under the 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 "Advanced"), but can 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 format sockets. The audio signal from pickups has its own specific characteristics, so the instrument input typically features a higher input level and special impedance matching to ensure optimal sound quality.

The presence in the audio system of its own LCD display. Such displays may have different characteristics: in some models, these are the simplest indicators in which symbols are made up of separate luminous fragments (similar to how numbers are made up of separate “sticks” in the simplest electronic watch); in others — full-fledged matrices with an image formed from pixels. However, anyway, the display makes the control of the audio system more convenient and intuitive, because. can display various additional information — the selected signal source, track name, RDS data (see above), equalizer settings, error messages and much more.

A remote control is included with the audio system. The convenience of this function is obvious: instead of having to approach the device every time to change the operating parameters, you can give a command from the remote control without getting up.