Comparison KEF LSX vs KEF LS50

— Active. Acoustic systems equipped with their own built-in power amplifier. A line-level signal (from the preamp) is sufficient for these speakers, making them extremely easy to use. On the other hand, the built-in amplifier requires power, so these speakers have to be plugged into an outlet as well.

— Passive. Speaker systems that do not have a built-in power amplifier. Accordingly, you need to connect such speakers to an external amplifier (or a device that has such an amplifier — for example, an audio receiver), while paying special attention to component compatibility. On the other hand, passive acoustics are considered more suitable for creating high-end audio systems than active ones: it allows you to choose a power amplifier of your choice, moreover, there are no “extra” electronics in the speaker cabinet, which reduces the likelihood of interference.

— Passive / active. Acoustic systems combining passive main speakers with an active subwoofer. For a number of technical reasons, active subwoofers are more convenient than passive ones: in particular, they save the user from having to look for a specialized low-frequency amplifier, and they provide more tuning options (the latter can be useful for “fitting” sound into a particular room). Therefore, many manufacturers produce passive-active kits.

Speaker sensitivity.

This characteristic is indicated on the basis of how loud the acoustics are capable of producing when a signal of a certain standard power is applied to it. Simply put, the higher the sensitivity of the speaker, the louder it will sound at the same output power of the amplifier. Thus, sensitive acoustics can be effectively used even in combination with relatively low-power "amplifiers". On the other hand, low sensitivity also has its advantages: it allows you to achieve a more uniform frequency response and reduces the likelihood of overloading the amplifier. In the least sensitive modern speakers, this indicator does not exceed 84 dB, in the most sensitive it is 95 – 96 dB or more.

Note that in fact, you have to pay attention to this parameter when acoustics are planned to be used with a separately selected power amplifier. Therefore, for active systems (see "Type"), sensitivity is purely a reference value, and, usually, it can be ignored when choosing.

Impedance is the nominal electrical impedance of a speaker system. Nowadays, a set of standard impedance values are used; the most widely used speakers are 4 ohms, 6 ohms, 8 ohms and 16 ohms.

This parameter is of primary importance for passive acoustics (see "Type"). When connecting such speakers to a power amplifier, it is highly desirable that their impedance matches the speaker impedance for which the amplifier is designed; in case of a mismatch, either overload and distortion in sound (if the speaker impedance is below optimal), or a decrease in power (in the opposite case), are possible.

As for active acoustics, here the impedance is mainly of reference value — the speakers in such systems are initially selected for the corresponding amplifiers. However there is an opinion that a higher resistance reduces the level of interference and has a positive effect on the purity of the sound; however, the difference in impedance between different models is usually not so great that this effect is noticeable against the background of other factors that determine sound quality.

The crossover frequency provided in the speaker design.

A crossover is installed exclusively in a multi-band model (see "Number of Bands"). This is an electronic filter that ensures the division of the incoming audio signal into separate frequency ranges and directs each range to "its" set of speakers. And the crossover frequency shows where the boundary between these ranges lies. If there are more than two bands, there will be several such boundaries: for example, for a four-band system it may be specified "0.15 / 0.8 / 2.8 kHz" or "0.12 / 1 / 3.8".

In most cases, this parameter has mainly a reference value: the frequencies of the built-in crossover are selected to match the operating characteristics of the speakers installed in the speaker system.

The highest power rating of an amplifier that the loudspeakers can handle safely. Too much input power can damage the speakers, so when connecting, make sure that the amplifier's characteristics do not exceed the capabilities of the speakers. It is worth noting that this parameter may be slightly higher than the total nominal power of the acoustics (see below), since in this case we are only talking about the safety of the equipment, and not about the absence of distortion in the sound.

The total rated power of all speaker components, in other words, the sum of the powers of all speakers. As a nominal one, they usually indicate the highest average (rms) power at which acoustics can operate for a long time without overloads and damage. In this case, individual power surges can significantly exceed this value, however, it is the rated power that is the main characteristic of any speaker.

First of all, the sound volume depends on this characteristic: the more powerful the speakers, the louder the sound they can produce if there is a suitable amplifier. In addition, in passive and passive-active models, compatibility with an external amplifier also depends on the power: the output power of the “amplifier” should not exceed the power of the acoustics connected to it, otherwise overloads and even breakdowns are possible.

Detailed recommendations regarding the choice of speakers for power for a particular situation can be found in special sources. However, in general, an indicator of up to 100 W by the standards of modern acoustics is considered quite modest, 100 – 200 W — average, 200 – 300 W — above average, and the most powerful sets give out up to 500 W or even more.

In conclusion, we note two more nuances. Firstly, when comparing different systems according to this ch...aracteristic, one must also take into account the sound format in which they work. In particular, if there is a subwoofer, it can account for a significant part of the total power — up to half or more. As a result, for example, a 2.1 set of 50 W with a 20-watt subwoofer at the main frequencies will not be able to pull out the same volume as a 40-watt 2.0 system: in the first case, each main channel will have only 15 watts, in the second — 20 watts. Secondly, in multichannel systems, the total power can be distributed among the channels in different proportions; so, say, two 5.1 systems with the same total power can differ markedly in front and rear balance at maximum volume.

The total frequency range that the speaker is capable of reproducing. Specified from the bottom of the range in the lowest frequency component to the top of the range in 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.

The wider the frequency range — the fuller the reproduced sound, the lower the likelihood that some part of the low or high frequencies will be "cut off". It is worth noting here that the human ear perceives frequencies on average from 16 Hz to 22 kHz, and from a practical point of view, it makes no sense to provide a wider frequency range in speakers. However, quite a few models go beyond this range, sometimes quite significantly (for example, there are speakers with a range of about 10 – 50,000 Hz). Such characteristics are a kind of "side effect" of high-end acoustics, and they are usually given for advertising purposes.

Thus, the lower limit of the range in modern speakers can be within frequencies up to 20 Hz, however, higher values \u200b\u200bare more common — 30 – 40 Hz, 40 – 50 Hz, or even more than 70 Hz. In turn, the upper limit in most modern speakers lies in the range 19 – 22 kHz, although there are deviations both upwards (see above) and downwards.

Types of inputs provided in the design of the AU.

Note that the standard high-level terminal-based inputs used to connect passive acoustics to power amplifiers are not indicated in this list — their presence in the corresponding types of speakers is assumed by definition. The rest of the options could be:

— RCA. Inputs for working with analogue audio signal using RCA connectors (this connector can be used in other interfaces, but they have their own names). Usually, they are used in active systems and are designed for a line level signal, however, in some models, RCA is intended for connection to a power amplifier. In general, this interface does not differ in noise immunity, but its capabilities are quite enough at least for home acoustics, including quite advanced ones. Note that with this connection, each audio channel requires its own connector; therefore, RCA jacks are usually installed in pairs — stereo left and right.

— mini-Jack (3.5 mm). Standard connector for most modern portable audio equipment. The speakers are mainly used to connect similar 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.

— Jack (6.35 mm)....A connector similar in shape to the mini-jack described above, but having a larger size; as a result, it is found mainly in stationary audio equipment, and is also used in musical instruments. 6.35 mm Jack is considered more durable and reliable than 3.5 mm mini-jack, besides, it is technically able to provide the so-called balanced connection (see below), although in fact this is rarely possible. To do this, this connector can be combined with an XLR connector (combo port), which allows you to connect one of the types of plugs of your choice.

— Balanced XLR. XLR connectors have three pins, according to the number of cable strands. They can be used to transmit a different type of signal, but in this case, an analogue balanced connection is implied. With this connection, one channel of audio is transmitted per connector, and a fairly large part of the interference that occurs during transmission is extinguished by the cable itself. The latter ensures the purity of the transmitted sound even at fairly large distances (of the order of several metres). Balanced XLR refers to professional interfaces and is found mainly in speakers of the corresponding class. Can be combined with a Jack (6.35 mm) connector (combo port), which allows you to connect one of the types of plugs of your choice.

— Balanced digital AES/EBU. A variation of the XLR interface, designed to transmit a signal in digital format. It also belongs to professional ones, uses the same connectors and cables and the same balanced transmission method, which ensures the cancellation of most interference; however, due to differences in the type of signal, it has a large bandwidth and allows even multi-channel audio to be transmitted through one connector.

— Optical. One of the varieties of the S / P-DIF standard is, along with the coaxial one described below. 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.

— Coaxial. 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.

— Speakon. Professional interface used to connect the signal from the power amplifier to the speakers. It is used in the technique of the corresponding class, in particular, concert systems (see "Purpose"). Due to the features of the connectors (presence of latches, high degree of isolation) it can be used even with the most powerful amplifiers.

— USB port. The USB interface in speaker systems can have different purposes and use different types of connectors; these points should be clarified separately. So, one of the most popular formats for using this input is connecting speakers to the USB port of a PC or laptop to work as computer acoustics; models with this capability are equipped with USB Type B connectors — a characteristic square shape. Such acoustics will be useful, in particular, if the computer's specialized audio inputs are busy, out of order, or not available at all; in addition, it is often equipped with high-end built-in DACs and allows you to achieve higher sound quality than the average sound card.
There is another option — speakers with USB A inputs and built-in players that can independently play music from a flash drive or other external drive, as well as charge various gadgets like smartphones via USB.

Passive models (see "Type") are usually equipped with so-called high-level inputs designed for a signal from a power amplifier; this is a separate category of connectors installed in such models by default.

Types of outputs provided in the design of the speaker system.

Outputs in modern speakers are mainly used to switch the signal coming from an external source. However, other applications are also possible: for example, a speaker with a USB port (see "Inputs") and a built-in player may have connectors for connecting additional acoustics. The most common types of exits are:

— RCA. In this case, we mean an output for working with an analogue audio signal, usually a line level (an RCA connector can also be used in other interfaces, but they have their own names). In general, this interface does not differ in noise immunity, but its capabilities are quite enough at least for home acoustics, including quite advanced ones. Note that with this connection, each audio channel requires its own connector; therefore, RCA jacks are usually installed in pairs — stereo left and right. The exception is the subwoofer outputs, which can also be performed in this format — one connector is enough for them.

— mini-Jack (3.5 mm). Standard mini-jack socket. Most often used in the same way as RCA described above — for line-level analogue audio, including connecting subwoofers. At the same time, one 3.5 mm jack can be responsible for two stereo channels at once, however, the noise immunity of such an interface is even lower than that of RCA. Therefore, such a connector among the speakers is much less common.
Separately, we emph...asize that the headphone output (see below) is indicated separately, even if it also uses the mini-Jack jack.

— Jack (6.35 mm). A connector similar in shape to the mini-jack described above, but having a larger size; as a result, it is found mainly in stationary audio equipment, and is also used in musical instruments. 6.35 mm Jack is considered more durable and reliable than 3.5 mm mini-jack, besides technically it is able to provide the so-called balanced connection (see below), although in fact this possibility is relatively rare. One of the most popular uses for this output is connecting an additional speaker to a live speaker. Along with its younger brother, the 6.35 mm Jack connector can be used as a headphone output, but headphone jacks are not included in this category and are listed separately (see below).

— Headphones. Dedicated headphone output. Most modern "ears" have mini-Jack plugs (see above) — respectively, and this output is equipped with just such a connector. Occasionally there are speakers with Jack jacks, but this point is not important — a 3.5 mm plug can be connected to a 6.35 mm jack using a simple adapter (such adapters are even supplied with many headphones). Headphones can be useful, for example, at a later time of the day when loud music is undesirable — or vice versa, in a noisy environment, in order to hear the sound better; at the same time, the speaker is often closer to the listener than the player or other signal source, and it is most convenient to connect the “ears” to the speaker.

— Balanced XLR. XLR connectors have three pins, according to the number of cable strands. They can be used to transmit a different type of signal, however, in this case, an analogue balanced connection is implied. With this connection, one channel of audio is transmitted per connector, and a fairly large part of the interference that occurs during transmission is extinguished by the cable itself. The latter ensures the purity of the transmitted sound even at fairly large distances (of the order of several metres). Balanced XLR refers to professional interfaces and is found mainly in speakers of the corresponding class.

— Balanced digital AES/EBU. A variation of the XLR interface, designed to transmit a signal in digital format. It also belongs to professional ones, uses the same connectors and cables and the same balanced transmission method, which ensures the damping of most interference; however, due to differences in the type of signal, it has a large bandwidth and allows even multi-channel audio to be transmitted through one connector.

— Optical. One of the varieties of the S / P-DIF standard — along with the coaxial described below. 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.

— Coaxial. 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.

— Speakon. A professional interface used to work with the signal coming from the power amplifier. It is used in the equipment of the corresponding class, in particular, concert systems (see "Purpose") — in this case, we are talking about connecting additional passive speakers to such a speaker. Thanks to the features of the connectors (presence of latches, high degree of isolation), the Speakon interface can be used even with the most powerful amplifiers.