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.
System power
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.
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).
Lighting effects
The presence in the audio system of the function of
light effects. Usually, this is the backlight of the speakers and/or the front panel, which can change brightness and colour, blink, etc.; the rhythm of work can be independent or synchronized with the track being played in the light music mode. This function practically does not affect the main functionality of the device, its purpose is purely decorative.
Operating hours
Audio system operating time without connection to an external power source (network or USB port, depending on the capabilities). Note that manufacturers tend to indicate battery life in their specifications under optimal conditions for energy saving: at low volume, without using additional functions, etc. Therefore, in fact, this indicator may be noticeably lower than the claimed one, and speakers with a long operating time will not sound at full volume for the specified hours.
