How to connect a horn from speakers. Features of the use of loudspeakers in public address systems

Horn acoustics

Horn acoustics has always been more expensive than usual. And it is not surprising that the most ardent fans of such acoustics are those users who once owned traditional speakers.
There is nothing surprising in this. A sophisticated listener will always appreciate the overall harmony, integrity of perception and naturalness of sound.
The user himself likes horn acoustics in view of their musicality and ability to capture the listener.

What it is

Modern audio equipment is capable of reproducing the entire range of required frequencies. This is enough to transmit musical compositions, but not enough to create a sense of the presence of the listener.
As any music lover will tell you, there is something that is responsible for the transmission of not just music, melody, but also for the transmission of the performer's emotions. Horn acoustics just perfectly copes with this matter.
Horn acoustics are not designed like conventional ones. The speaker (see) in it is not quite large in size and it joins the horn, which increases the volume of its sound.
This can be compared with the case when a person, in order to shout to an interlocutor at a great distance, folds his hands with a mouthpiece.

Note. If you are thinking about purchasing horn speakers in your car, we hasten to warn you: the difference between good and bad horn speakers is very significant than is observed in traditional versions.
Cheap horn acoustics made by an unscrupulous manufacturer cannot in any way act as a comparison. It was these cheap options that gave rise to rumors that supposedly horn acoustics are good, but the sound in them is colored.

As for high-quality horn speakers, they are always expensive. They always use Alnico magnets and exotic metal diaphragms.
Horn acoustics are always assembled according to strict tolerances and dimensions. In a word, such a production technology cannot imply any compromises and cost reduction.

Let's give examples. A two-inch TAD compression driver, used in all Cesaro horn acoustics, costs about 1,000 euros. At the same time, the most expensive tweeter to date is the beryllium-diaphragm Scan Speke, which only costs about $600.

Horn acoustics for cars are always unique products produced in series. The names of some in gold letters are inscribed in the history of car audio.
For example, this is the Japanese horn acoustics Maxonik, which has been produced since 1932. Today Maxonic always presents high-tech products.
When creating, expensive technologies are always used with the use of magnetic systems in emitters.

Story

So:

• It will be interesting to know that the very first loudspeakers in the world were horn-type. They appeared in the 20s of the last century.
  The technology of creation was the only one and then they simply did not know how to make other acoustic systems;
• Ten years later, speakers appear that are already similar to today's versions of traditional acoustics. They immediately gained great popularity, but forgot about horn acoustics.
  Then it was mistakenly believed that the ideal place for horn acoustics would be the sounding of large spaces, and for pleasant listening to music, it is simply not suitable;
• Another ten years pass and the famous American engineer creates a completely new design of horn acoustics. It was Paul Klipsch (that was the name of the engineer) who proved that horn acoustics would make it possible to reproduce musical compositions with very high quality.

Note. It was then that the engineer founded a company producing horn acoustics, which to this day is a world leader. The company was called Klipsch, and speakers of this type were called Klipsch.

• Interestingly, music lovers immediately "figured out" that the "clips" reproduce music in a special way. Since that time, horn acoustics have become the choice of a rather narrow circle of connoisseurs of real music;

• The second half of the last century was marked by the appearance of completely new carriers. In addition, there are new developments and new approaches for processing and amplifying the audio signal;
• Finally, having reached the apogee of modernization and improvement, people began to realize that the sound had not been able to give "liveness". And then the eyes of many turned to horn acoustics, which began a real boom about three years ago.

The magical sound of horn systems

So:

• The fact that horn acoustics sounds in a special way is not difficult to verify. And for such a sound there are all the prerequisites. Firstly, horn acoustics are highly sensitive. This makes it possible to reproduce the most subtle nuances, convey the emotions of the performer;
• Secondly, horn speakers produce sound waves that are more "natural" in nature compared to the air vibrations coming out of traditional speakers;
• Horn acoustics can reproduce low frequencies, but its dimensions depend on this. In other words, the lower frequencies you have to reproduce, the larger the size of the horn speaker should be.

Note. It is for this reason that horn acoustics are used for the most part for reproducing midrange and treble, but if you choose larger speakers for yourself, then bass will be reproduced at the highest level.

• And that's not all. Low frequencies will be reproduced not just like that, but at the highest level. True, only the most subtle connoisseurs of sound can distinguish the difference in reproduction.

Note. It is interesting that recently quite often there are speakers where only the tweeters are made in the form of a horn. For example, the same speakers of the Clipsch Reference series are made according to this model.

• The high frequencies reproduced by horn speakers sound much louder. Needless to say, the HF quality is better than when using conventional tweeters.

Recently, among the manufacturers of horn acoustics, I would like to single out the Italian company Zingali separately. The engineers of this company have created an original horn radiator that simultaneously reproduces midrange and high frequencies, and at the same time looks beautiful.

Horn acoustics in a car

Needless to say, all traditional car speakers do not allow you to achieve high sound quality. It's not about anything, but in a cramped cabin.
Here the horn ones will give a chance to significantly exalt the sound, create the effect of presence (as if you are sitting in a studio or at a concert). The explanation can be simple: the horn increases the distance over which sound waves propagate, while increasing the density of sound and giving a characteristic melody.
Technical solutions for placing such acoustics in a car can be different:

• So, the most popular way is to install the loudspeaker in front, frontally on the wall of the case, inside which the main waveguide is formed. It has an outlet to the outside;
• Another option involves a horn system, where there is a woofer. It is placed in a separate building. The same fate is followed by tweeters and midrange speakers, which are also placed in the corresponding case separately from each other.

Advantages and disadvantages of horn acoustics

This concludes our review of horn acoustic systems. Recently, they have been increasingly installed in cars with their own hands, using step-by-step instructions, useful video reviews, drawings and photo materials.
The price of good horn acoustics is very high, but this will not stop ardent music lovers.

Loudspeakers are used in various fields of human activity: in industry, transport, sports, culture, and everyday life. Recently, much attention has been paid to the field of human security, in which fire warning systems, emergency warning systems, public address systems, public address systems are being built. The main task of each of these systems is to alert people - to bring them information about a particular threat. The main executive element of each of these systems is a loudspeaker, the correct choice of which can affect the feasibility of the system as a whole and its budget.

To ensure the safety of people in buildings and structures, integrated security systems are being built, part of which is the system for warning and managing the evacuation of people SOUE. The main task of the SOUE is to alert people, to bring them information aimed at ensuring their personal safety. SOUE is a complex of technical means and organizational measures. The loudspeaker is the final executive element of the technical means of the SOUE, and its parameters are input for the electro-acoustic calculation - part of the organizational measures.

Based on the existing regulatory documentation (ND), the following requirements are imposed on the loudspeaker:

SOUE voice annunciators must provide a total sound level of at least 75 dBA at a distance of 3 m from the annunciator, but not more than 120 dBA at any point of the protected premises, reproduce normally audible frequencies in the range from 200 to 5000 Hz. The sound level of information from voice annunciators must comply with the rules of the set of rules (see FZ-123, set of rules SP-3-13130-2009, dated 2009, "Fire safety requirements for sound and voice notification and management of people evacuation").

To meet the requirements set forth in the ND, an integrated approach is needed, which takes into account both the characteristics of the loudspeaker, due to the parameters of the sound amplification system, and its design features, due to the sounded environment - acoustics, configuration and noise in the room. To perform an electroacoustic calculation, it is necessary to take into account such loudspeaker parameters as sensitivity and electric power, which determine its loudness, the amplitude-frequency characteristic, which determines its quality, and the directivity diagram, which determines its directional properties.

Currently, a large number of loudspeakers are produced, differing in characteristics, in design, in protection class, which determines the scope of their application.

A loudspeaker is a converter of an electrical signal into an acoustic one. The main parameter that determines the efficiency of a loudspeaker is its efficiency. To date, the approach has been established, according to which the loudspeaker should provide the maximum sound pressure on the working axis with a constant voltage (sound signal) to its input. This approach involves the simultaneous solution of two problems at once: the formation of the required loudness and, at the same time, the efficiency of the loudspeaker.

When choosing a loudspeaker for a public address system, it is necessary to have a basic understanding of its features: device, operation, basic physical principles underlying it. So, for example, the first acquaintance with a loudspeaker involves the question: is it of high quality or not. Answer: the quality of a loudspeaker, in the simplest case, is determined by the width and unevenness of its frequency response. The second issue is usually related to loudness. Loudness is sometimes mistakenly identified with the power of the loudspeaker, although this is not at all the same thing. The electrical power of an audio signal, measured in watts, applied to a loudspeaker does determine its loudness, but to a much lesser extent than its "sensitivity-sound pressure" measured in decibels. When working with a loudspeaker, it is necessary to clearly understand the following main dependencies. The sensitivity of the loudspeaker is inversely related (Mat. Cf. is inversely proportional) with the quality: the higher the sensitivity, the worse its quality and vice versa. Therefore, in order to get more volume, we must sacrifice quality. To simultaneously achieve both quality and loudness, a large electrical power is supplied to the loudspeaker. Another dependence is related to the directivity characteristic (CH) of the loudspeaker. XH is determined by the method of radiation and the design features of the loudspeaker. For example, horn loudspeakers have high sound pressure and a narrow polar pattern (they are loud and highly directional). Thus, there is one more dependence: “directionality - loudness”. The higher the directivity of the loudspeaker, the higher its volume (Mat. cf. direct proportionality). Narrow directivity is always associated with a deterioration in the quality of the loudspeaker: a narrowing of its frequency range in the low-frequency region, which can be considered as the third fundamental dependence.

For ease of use, loudspeakers are classified according to characteristics, design features, and applications. According to the characteristics, loudspeakers can be divided into classes (narrowband and wideband), which determine the sound quality and directionality (narrowband and broadband). So, for example, broadband loudspeakers are used for background sounding - hypermarkets, fitness centers; narrowband - for voice announcements - gas stations, parking lots, railway platforms, stations. Consideration of the loudspeaker radiation pattern is necessary when sounding distributed territories. Wide-range loudspeakers cover a large circular area, narrow-beam speakers cover a smaller circular area, but at the same time “punch through” a greater range. By varying the DN of loudspeakers, it is possible to optimize their number and at the same time reduce the budget of the entire public address system as a whole. So, for example, one sound projector used for scoring corridors can replace four wall or ceiling speakers. By design, loudspeakers can be divided into internal (IP-41) used for sounding heated rooms, and external (IP-54) used for sounding open areas. For industrial facilities dealing with aggressive substances, explosive facilities, a higher protection class (IP-66/67) may be required.

Taking into account the features and capabilities of a particular loudspeaker will make it possible to form a more competent, optimal technical solution.

2. Loudspeaker device

Figure 1 shows a simplified diagram of the loudspeaker operation.

Fig. 1 - Simplified diagram of the functioning of the loudspeaker

The loudspeaker contains the following subsystems:

• EL - electric;
• EM - electromechanical;
• MA - mechanical-acoustic;
• AK - acoustic.

Electrical subsystem performs the function of matching the input impedance of the electrical subsystem with the complex output impedance of the amplifier in the case of low-resistance matching, or the secondary winding of the step-up transformer in the case of using a translational amplifier.

Electromechanical subsystem is a device that converts an electrical signal at the input into mechanical vibrations of a moving element at the output.

Mechanical-acoustic subsystem serves to match the mechanical impedance of the loudspeaker with the frequency-dependent component of the radiation resistance formed by the radiator.

Acoustic subsystem, called the emitter, forms the radiation resistance, which determines the acoustic power of the emitter. and ultimately loudspeaker efficiency.

One of the most important parameters characterizing the efficiency of a loudspeaker is the coefficient of performance (COP). The efficiency of the loudspeaker is found from the ratio of the output acoustic power of the emitter to the input electric power of the loudspeaker and depends on the consistency of all subsystems as a whole.

3. Basic parameters of loudspeakers

The main parameter that determines the efficiency of a loudspeaker is its output sound pressure, measured in decibels. Sound pressure, in turn, is determined by two parameters - the sensitivity of the loudspeaker, measured under certain conditions, and its electrical power, measured in watts.

Speaker sensitivity

There are two types of sensitivity, characteristic and axial.

Characteristic sensitivity (dB) - the ratio of the average sound pressure developed by the loudspeaker in the nominal frequency range on the working axis at a distance of 1 m from the working center, to the square root of the electrical power supplied.

Recently, most manufacturers indicate axial sensitivity as a loudness characteristic.

Axial sensitivity (sometimes simply sensitivity) is the ratio of the sound pressure developed at a free field point selected on the working axis of the loudspeaker at a distance of 1m from the working center to the input power (usually 1W.).

Loudspeaker sound pressure

With an arbitrary value of the input electrical power P W, the sound pressure level of the loudspeaker (its actual loudness) can be determined as:

Loudspeaker power

There are many different definitions of loudspeaker power in the technical literature, which are not easy to understand.

In the recommendations of the International Electrotechnical Committee (IEC) 268-5 “Elements of electroacoustic systems. Loudspeakers” and 581-7 “Minimum requirements for Hi-Fi equipment. Loudspeakers" provides the following types of power.

Loudspeaker characteristic power– power at which the loudspeaker creates a characteristic sound pressure level of 94 dB at a distance of 1 m in the frequency range of 100...8000 Hz.

Noise power is determined by the test results of the loudspeaker on a special noise signal for 100 hours. the same signal is used to determine these types of power.

Maximum sinusoidal loudspeaker power- this is the power of a continuous sinusoidal signal in a given frequency range, which the loudspeaker can withstand without mechanical and thermal damage for a period of time (at least 1 hour) specified in the specification.

Loudspeaker Rated Power- this is the electrical power at which the nonlinear distortion of the loudspeaker does not exceed the required values.

Loudspeaker power rating- is defined as the highest electrical power at which the loudspeaker can work satisfactorily for a long time on a real sound signal without thermal and mechanical damage.

Today (at least in our country) the most commonly used are two types of power - nominal and sinusoidal.

Rated power (in addition to the definition above) is understood as the power at which, in a certain (average) position of the amplifier volume control, the non-linear distortion of the loudspeaker is minimal.

Today, most manufacturers specify sinusoidal power in their specifications.

Sinusoidal power (eng. RMS - Rated Maximum Sinusoidal) is the maximum sinusoidal power at which the loudspeaker must operate for 1 hour with a real music signal without suffering physical damage (cf. maximum sinusoidal power).

Additional speaker features

Rated electrical resistance is the input frequency-dependent (complex) loudspeaker impedance. In the case of low-impedance matching (in real acoustic systems (AS)) it has a value of 4/8 Ohm. In the case of high-voltage transformer matching - from hundreds of ohms to several kilo-ohms.

Effectively reproduced frequency range- the frequency range within which the sound pressure level is reduced by a certain specified value in relation to the level averaged over a certain frequency band. According to the recommendations of IEC 581-7 for the frequency band 50...12500 Hz, the value of this decrease (decay) is set equal to 8 dB in relation to the level averaged in the frequency band 100...8000 Hz.

Loudspeaker frequency response by sound pressure - this is a graphical or numerical dependence of the sound pressure level on the frequency of the signal developed by the loudspeaker at a certain point in the free field, located at a certain distance from the working center at a constant value of the voltage at the loudspeaker terminals. A more familiar name for this dependence is the amplitude-frequency response (AFC).

Uneven frequency response of sound pressure

The dependence of sound pressure on frequency is depicted on diagrams (in a Cartesian coordinate system) called the amplitude-frequency characteristics (the term AFC is the most familiar. In the technical literature, this dependence is called the frequency response of the sound pressure FHZD) of the loudspeaker.

Under the unevenness of the frequency response, one should understand the difference between the maximum P max (dB) and the minimum P min (dB), levels in the effective (declared) frequency range.

In accordance with OST 4.383.001, the frequency response unevenness in the effective operating frequency range should not exceed:

• 14 dB for wideband heads (loudspeakers);
• 10 dB - for midrange.

Figure 2 shows the loudspeaker frequency response with unevenness Δ (dB), in the range of 0.2-7 kHz, not more than 5%.

Fig. 2 - Irregularity of the frequency response in the range of 0.2-7 kHz

The uneven frequency response depends on:

• type of electromechanical converter;
• emitter dimensions;
• constructive (acoustic) design;
• frequency dependent input electrical and mechanical impedances,

and determines the quality of the speaker as a whole.

Loudspeaker directivity

Any loudspeaker radiates sound energy unevenly. The sound pressure level of a loudspeaker depends significantly on the angle at which the measurement is made. The loudspeaker radiates the greatest amount of energy along the working axis. The working axis, as a rule, coincides with the geometric axis of the loudspeaker passing through its working center (the working center coincides with the geometric center of symmetry of the loudspeaker outlet.). The dependence of the sound pressure of a loudspeaker on the direction is called the directivity characteristic.

Loudspeaker directivity(Rn) - the dependence of the sound pressure P Θ (dB) developed by the loudspeaker at a free field point (at a fixed distance from the working center, for example, 1m), on the angle Θ between the working axis of the loudspeaker and the direction to this point:

The graphical expression R n for different angles and frequencies is called the radiation pattern (DN). Most often, RPs are presented in polar coordinates, fig. 3.

Rice. 3 - Directional pattern of the ROXTON HP-10T loudspeaker at a frequency of 4 kHz.

The sound pressure on the diagram is indicated not in absolute, but in relative terms - decibels (dB).

4. Classification of loudspeakers for public address systems

The general classification of loudspeakers can be represented as follows, Fig. 4:

Rice. 4 - Classification of loudspeakers for public address systems

• according to the method of radiation (coordination with the environment);
• by connection method (to the amplifier);
• by characteristics;
• by area of ​​application;
• by design;
• by converter type.

According to the method of radiation

• loudspeakers (heads) of direct radiation;
• horn speakers.

Direct radiant loudspeakers radiate sound energy directly into the environment. The operation of a direct-radiation loudspeaker will be discussed below. In horn loudspeakers, the diaphragm is connected to the medium directly through the horn. The operation of a horn loudspeaker will be discussed below.

By connection method loudspeakers can be divided into:

• low-resistance;
• transformer.

With low-impedance matching, the loudspeaker is connected directly to the output stage of the power amplifier (PA). Transformer matching involves the use of a specialized transformer loudspeaker connected to the output of a broadcast amplifier, equipped with an additional step-up transformer. These approaches will be discussed in more detail below.

By frequency range(according to the width of the frequency response) loudspeakers can be divided into:

• low-frequency (LF): 40-200Hz;
• mid-frequency (MF): 200-3kHz;
• high-frequency HF) 3-20 kHz.

In practice, it is convenient to divide according to the principle "yes / no", "bad / good". So, depending on the width of the frequency response, loudspeakers can be divided into narrowband and wideband. A narrowband speaker is a loudspeaker that operates over a limited frequency range. So, for example, a horn loudspeaker can be called narrow-band; its effective frequency range is within the midrange ~ 0.3-3 kHz (according to the existing ND, loudspeakers should reproduce normally audible frequencies in the range from 0.2 to 5 kHz). Loudspeaker that works equally well in the low, mid and high ranges. will be called broadband. Public address systems use both types of loudspeakers. Broadband can be considered a loudspeaker covering (even partially) all 3 ranges. Broadband loudspeakers are widely used and are used to reproduce not only speech, but also musical information.

In order to classify loudspeakers depending on the directivity, it is necessary to introduce an additional, but very important and practical characteristic - the width of the directivity pattern of the SDN.

SRP is an additional characteristic determined from the polar RPs of the loudspeaker. According to the international standard IEC 268-5 (2000), SRP can be defined as the opening angle (deviation from the working axis) of the loudspeaker (cf. coverage angle), at which the sound pressure drops by 6dB (beam width -6dB) relative to the value measured at the working axes.

We will call narrowly directional loudspeakers whose SRP at a frequency of 4 kHz is less than 90 degrees, broadly directional - loudspeakers whose SRP at a frequency of 4 kHz is more than 90 degrees. These types are discussed in more detail in the introduction.

Depending on the design loudspeakers can be divided into:

• mortise (in a flat screen);
• overhead (open box);
• case (closed box);
• phase inverter (acoustic systems).

Mortise loudspeakers can also be of an open type (without a screen), since the screen for them is the surface itself (wall, ceiling) into which they are built. For economic reasons, overhead loudspeakers can be implemented in an open box, the back wall of which is the plane (wall) on which it is mounted. These issues will be discussed in more detail below.

According to the type of transducer, loudspeakers can be divided into:

• electrodynamic (coil);
• electrostatic (electret);
• electromagnetic (with a fixed coil);
• piezoelectric (tape).

To date, the most widely used electrodynamic coil loudspeakers. An electrodynamic coil transducer can be considered as an electromechanical subsystem that converts an electrical signal at the input into mechanical vibrations of a moving element at the output. This loudspeaker consists of two main subsystems: movable - voice coil and diffuser and magnetic - permanent magnet, core, top and bottom slates. Let's consider the operation of this system.

Classification of loudspeakers by application

In public address systems, loudspeakers have the widest range of applications: from quiet and closed rooms to noisy open areas, from voice announcements to high-quality musical arrangements.

Depending on the application, loudspeakers can be divided into 3 main groups:

1. Loudspeakers of internal execution – are used for scoring of the closed rooms. This group of loudspeakers is characterized by a low degree of protection (IP-41).
2. Loudspeakers of external design - used for scoring open areas. Such loudspeakers are called street loudspeakers. This group of loudspeakers is characterized by a higher degree of protection (IP-54).
3. Explosion-proof loudspeakers are used in explosive premises or areas with a high content of aggressive (explosive) substances. This group of loudspeakers is characterized by a high degree of protection (IP-67). Such loudspeakers are used in the oil and gas industry, at nuclear power plants, etc.

Each of the groups can be associated with the corresponding class (degree) of IP protection. The degree of protection is understood as a method that restricts access to dangerous current-carrying and mechanical parts, the ingress of solid objects and / or water into the shell.

The degree of protection of the shell of electrical equipment is marked with the international IP protection mark and two digits, the first of which means protection against ingress of solid objects, the second - against water ingress.

The most common for loudspeakers are the following degrees of protection:

• IP-41, where:
  • 4 - Protection against foreign objects larger than 1 mm.
  • 1 - Vertically dripping water must not interfere with the operation of the device. Loudspeakers of this class are most often installed indoors.
• IP-54, where:
  • 5 - Dust protection, in which some dust can enter inside, but does not interfere with the operation of the device.
  • 4 - Protection against splashes falling in any direction. Loudspeakers of this class are most often installed in open areas.
• IP-67 where:
  • 6 - Dust-tight, in which dust cannot enter the device, complete protection against contact.
  • 7 - During short-term immersion, water does not get inside in quantities that disrupt the operation of the device. Loudspeakers of this class are installed in places subject to critical influences. There are also higher levels of protection.

5. Speaker operation

Operation of an electrodynamic loudspeaker

Figure 5 shows the device of a direct-radiation diffuser loudspeaker with an electrodynamic coil-type converter.

Fig. 5 - The device of an electrodynamic loudspeaker

The main working unit of an electrodynamic loudspeaker is a diffuser, which converts mechanical vibrations into acoustic ones. The loudspeaker diffuser is set in motion by a force acting on a coil rigidly attached to it, which is in a radial magnetic field. An alternating current flows in the coil, corresponding to the audio signal that the loudspeaker should play. The magnetic field in the loudspeaker is created by an annular permanent magnet and a magnetic circuit of two flanges and a core. The coil, under the action of an electromotive force, moves freely within the annular gap between the core and the upper flange, and its vibrations are transmitted to the diffuser, which, in turn, creates acoustic vibrations propagating in the air.

Electrodynamic loudspeakers have good characteristics, a wide radiation pattern, a wide frequency range, an acceptable sound pressure level, which allows them to be used to solve the widest class of tasks - from music broadcasting to emergency notification. These loudspeakers are most often used for indoor installation in closed heated rooms.

Horn loudspeaker operation

A horn loudspeaker (horn) is a matching element between the driver (emitter) and the environment. The driver, rigidly connected to the horn, converts the electrical signal into sound energy, which is received and amplified in the horn. Amplification of sound energy inside the horn is carried out due to a special geometric shape that provides a high concentration of sound energy. The use of an additional concentric channel in the design makes it possible to significantly reduce the size of the horn while maintaining its quality characteristics.

The horn consists of the following parts, Fig.6.

Rice. 6 - The device of the horn loudspeaker

• a - compression driver;
• b - magnet;
• c - concentric channel;
• g - horn;
• e - metal diaphragm;
• e - voice coil.

The horn loudspeaker works as follows: an electrical sound signal is fed to the input of a compression driver (a), which converts it into an acoustic signal at the output. The driver is rigidly fastened to the horn (r), which provides high sound pressure (the horn may have the following names: megaphone, bugle, loudspeaker, reflector, pipe). The driver consists of a rigid metal diaphragm (a) driven by an (excited) voice coil (e) wound around a cylindrical (or annular) magnet (b). The sound in this system propagates from the driver, passing through a concentric channel (c), exponentially amplified in the horn (d), after which it enters the output.

6. The main types of acoustic design of loudspeakers

Loudspeakers are provided with enclosures to improve efficiency. According to the type of acoustic design of the case, loudspeakers can be divided, Fig. 7 into:

• loudspeakers in a flat screen, Fig. 7a;
• loudspeakers in an open case, Fig. 7b;
• loudspeakers in a closed case, fig. 7c;
• loudspeakers with phase inverter, fig.7d.

Rice. 7 - Types of acoustic design of loudspeakers

The flat screen eliminates the diffraction of the emitted wave around the emitter. In order for the loudspeaker to be effective, the dimensions of the flat screen must be commensurate with the wavelength: l > λ/4, where λ is the wavelength of the lower limit of the frequency range. So for f n \u003d 100Hz, l\u003e v / 4f n \u003d 340/400 \u003d 0.85 m. The 80 cm screen is too large, therefore, in practice, the design of an open case (can be considered as a non-flat screen), which also prevents sound diffraction (envelope), is most used.

Let's consider a variant of acoustic design of the "closed box" type using the example of a widespread type of broadcast loudspeakers - a sound column.

Sound column device

The sound column is widely used in sound broadcast systems. Depending on the protection class, the sound column can be used for sounding both indoor and outdoor areas. The sound column is a closed box (box), with a group of vertically placed heads (speakers) placed inside, Fig.8.

Rice. 8 - Transformer-type sound column device

The speakers in the sound column are located inside the case one above the other, connected in parallel and connected to the output winding of a step-down transformer. The sound column belongs to the type of so-called. “linear group radiators” with a favorable RP - narrow in the vertical plane and wide in the horizontal. The cabinet design improves efficiency in the low-frequency region. The exacerbation of the pattern in the vertical plane is due to the interference of signals from each speaker. When designing a sound column, it is very important to ensure that the characteristics of the speakers installed in the same enclosure are identical and in phase.

Bass reflex speaker

A closed cabinet is a very effective solution, but the excess sound pressure density inside the cabinet creates standing waves that cause resonant effects, creating peaks and dips in playback. This effect can be minimized by using a phase inverter, which eliminates excess pressure inside the case. It is known that good reproduction of low frequencies can be ensured not only by the mass of the loudspeaker, but also by the volume of the case. A phase inverter is a channel (hole or pipe) in the wall of a closed box and allows you to minimize the volume of the cabinet while maintaining the uniformity of the frequency response in the bass region. The phase inverter acts as a resonator, considered as a second loudspeaker. The parameters of the opening of the phase inverter are selected in such a way as to balance the resonant effects at certain frequencies and minimize possible dips in the frequency response. Bass-reflex loudspeakers are called acoustic systems (AS). The appearance of the speakers is shown in Fig.9.

The example shown in Figure 9 demonstrates the main features of the implementation of high-quality acoustic systems.

The high quality of speaker sound is ensured by:

• creation of a voluminous, constructively thought-out case;
• the use of a phase inverter;
• multiband performance.

Multiband performance involves the use of several loudspeakers in one cabinet, which, in turn, requires the use of a crossover filter. In the speakers, the main contradiction due to physical principles is resolved - high efficiency at HF ​​can be achieved using small volume loudspeakers (HF drivers, HF driver - a diaphragm placed in a magnet (called a tweeter) and connected to a horn is an effective emitter at HF ); to reproduce low frequencies, a massive and voluminous loudspeaker (woofer) is required, which, in turn, is installed in a voluminous case.

An example of the implementation of budget broadband loudspeakers

There are several ways to increase the efficiency of a loudspeaker while maintaining its cost.

Construction of a two-cone system, fig.10.

A two-cone system consists of a main (large) cone, the role of which is played by a diffuser, and an additional (small) cone - a small horn, rigidly fastened to the diffuser. The concentric arrangement of these cones allows for high efficiency over a wide range and good uniformity at mid frequencies.

Improving the uniformity of sound in a wide frequency range can be achieved by building a multi-band speaker. In multiband systems, crossover filters are used to obtain voltage at the desired frequency (the filter is calculated for a certain frequency, beyond which the desired attenuation slope is provided. The first-order filter contains 1 element and provides attenuation with a slope of 6dB / octave; the second-order filter contains 2 elements and provides attenuation with a slope of 12dB/octave).

Figure 11 shows an example of the implementation of a budget two-way AS.

This loudspeaker uses a first-order crossover filter. The HF head (driver) of the loudspeaker is located on a ball joint, which allows you to vary the HF pattern. Convenient swivel mounts provide ease and convenience of installation.

Another important advantage of multiband speakers is to ensure the constancy of the directivity characteristic (CH) in a wide frequency range, which greatly simplifies the electroacoustic calculation.

For an example of classifying loudspeakers by design using ROXTON as an example, see the article "ROXTON Loudspeakers: Classification" .

7. Transformer loudspeakers

Transformer loudspeakers - loudspeakers with a built-in transformer, which are the final executive elements in wired broadcasting systems, on the basis of which fire warning systems, local public address systems, and loud-speaking communication systems are built. In such systems, the principle of transformer matching is implemented, in which a single loudspeaker or a line with several loudspeakers is connected to the high-voltage output of a broadcast amplifier. Signal transmission in a high-voltage line allows you to save the amount of transmitted power by reducing the current component, thereby minimizing losses on the wires. In a transformer loudspeaker, 2 stages of conversion are carried out. At the first stage, with the help of a transformer, the voltage of the high-voltage sound electrical signal is lowered, at the second stage, the electrical signal is converted into an audible acoustic sound signal.

Figure 12 shows the back of a cabinet wall-mounted transformer loudspeaker. The transformer loudspeaker consists of the following parts:

Fig. 12 - Transformer loudspeaker device

The loudspeaker housing, depending on the application, can be made of various materials, the widest of which today is ABS plastic. The housing is necessary for ease of installation of the loudspeaker, protection of current-carrying parts from ingress of dust and moisture, improvement of acoustic characteristics, formation of the necessary radiation pattern (SDN).

The step-down transformer is designed to lower the high voltage of the input line to the operating voltage of the electrodynamic converter (speaker). The primary winding of a transformer can contain multiple taps (eg full power, 2/3 power, 1/3 power), allowing the output power to be varied. The taps are marked and connected to the terminal blocks. Thus, each such tap has its own impedance (r, U) - reactance (of the primary winding of the transformer), depending on the frequency.

The terminal block provides the convenience of connecting the broadcast line to various taps of the primary winding of the transformer loudspeaker.

Speaker - a device for converting an electrical signal into an audible (audible) acoustic signal. It is connected to the secondary winding of the step-down transformer. In a horn loudspeaker, the role of the speaker is performed by a driver rigidly fastened to the horn.

8. Connecting loudspeakers to a sound reinforcement system

There are two main ways to match loudspeakers to a sound reinforcement system:

• low resistance;
• transformer.

Low impedance matching

With "low-impedance" matching, the loudspeakers are connected directly to the PA output stage. Depending on the implementation of the amplifier, there are many different inclusions.

On fig. 13 shows an option for including a low-impedance 4/8 ohm loudspeaker in the collector circuit of the output transistor.

Fig. 13 - Turning on a "low-resistance" loudspeaker in the collector circuit of a transistor

Connecting low-impedance speakers

According to the state standard (GOST R 53575-2009 (IEC 60268-5:2003). Loudspeakers. Electroacoustic test methods), loudspeakers can have two standard “impedances” - 4 and 8 ohms, for which low-impedance UMZCH outputs are designed.

With "low-resistance" load matching with the PA output, it is necessary to provide 2 conditions:

• the total impedance of several low-impedance loudspeakers should be within - 4-8 ohms;
• the total power of the load (several loudspeakers) must be higher than the output power of the amplifier;

therefore, connecting several “low-impedance” loudspeakers to one amplifier is carried out only in certain ways:

• sequentially;
• parallel;
• series-parallel.

When connected in series, the total load impedance Z is the sum of the impedances of each of the loudspeakers:

When connected in parallel, the total load impedance Z is the sum of the conductances (1/Z i) of each loudspeaker:

Based on the fact that there are only two standard impedances (4 / 8 ohms), no more than 2 loudspeakers are involved in a serial and parallel connection. Total impedance when two loudspeakers are connected in series (7):

Total impedance when two loudspeakers are connected in parallel (8):

The connection of a larger number of loudspeakers is carried out by a series-parallel connection, fig.14.

Fig.14 - Connection options for low-impedance loudspeakers

With an odd number of loudspeakers, it is necessary to make a series-parallel connection, the total impedance of which should fall within 4-8 ohms. The expected power, in this case, can only be obtained approximately, approximating the characteristics of the amplifier used for 4 and 8 ohm loads.

9. Transformer matching

Amplifiers that include a matching transformer are called translational, and loudspeakers that work with them are called transformers.

Broadcast systems using this principle are very effective for sounding large (distributed) territories.

The principle of transformer matching allows:

Transformer matching has another important advantage, it allows you to implement almost any topology - bus, star, tree, without changing the design principles. The main principles of designing broadcasting systems include the following:

• loudspeakers to the sound amplification system are connected only in parallel;
• the total load power of the amplifier is the sum of the power of an individual loudspeaker;
• the maximum power of the amplifier must exceed the total load power by more than 1.25 times;
• it is advisable to connect transformer loudspeakers only to specialized (broadcast) amplifiers equipped with an output transformer.

Translation system

The broadcast warning system can be considered within the framework of a three-stage transformation system including:

• a source;
• full amplifier;
• loudspeaker, fig.15.

Rice. 15 - Sound broadcast system

A low-level voltage signal (1-10mV) from the microphone is fed to the input of the broadcast amplifier, which includes:

• pre-amplifier (PU), which amplifies a low-level (1-10mV) audio signal to a level of 0.7-1V;
• a power amplifier (PA) that further amplifies the audio signal;
• a matching transformer that increases the voltage of the amplified audio signal to a voltage of 15-120V, depending on the standard used;
• transformer loudspeaker - a loudspeaker with a built-in matching transformer.

The option of matching the PA output with a transformer loudspeaker is shown in Fig. 16.

Rice. 16 - Transformer matching PA with a loudspeaker

The step-up transformer at the output of the amplifier is designed to further increase the voltage of the audio signal in order to optimally match it with the loudspeaker line. To implement multi-variant control, the secondary winding of the step-up transformer is supplied with several taps with different voltages: U nom, 3/4U nom, 1/2U nom, 1/4U nom.

The loudspeaker transformer lowers the voltage of the high-voltage audio to the level:

To implement multi-variant control, the primary winding of the matching loudspeaker transformer is supplied with several taps with different impedances: Z nom, 2/3Z nom, 1/2Z nom, 1/3Z nom.

Loudspeaker power, depending on the voltage in the line, U l, V and the selected impedance Z nom (Ohm):

This formula, which follows from Ohm's law for a circuit section (J=U/R) and the ratio for finding power (P=J*U), is very widely used in practice.

It can be seen from formula (6) that with a constant loudspeaker impedance, a decrease in the voltage in the line by n times (for example, when switching the line from terminal U 1 to terminal U 2, Fig. 16), leads to a decrease in loudspeaker power by n 2 times.

Transformer connection, in addition to optimal matching, has another advantage, which is the ease of calculating the total load as the sum of the powers of all loudspeakers connected to the broadcast amplifier:

Practical example

The warning system has been built, load lines are connected to the amplifier output, the total power of which is 0.7 ... 0.8 of the power of the amplifier.

Question: Is it possible to increase the amount of load on the existing amplifier (connect more speakers)?

Answer: You cannot increase the load power. But, there is an option. When switching the loudspeaker line from the output terminals U 1 \u003d 100V of the amplifier to the output terminals U 2 \u003d 70V, the power of the entire load (each speaker) will decrease by 2 times (form 6), which will free up 50% of the amplifier power.

Basic connection topologies for transformer loudspeakers

In distributed systems, a sufficiently large number of loudspeakers can be connected to one amplifier, which, for ease of design and control, are divided into groups - connected to separate lines (loops). The convenience of design and calculation is due to the fact that the lines to the output of the amplifier can be connected in various ways, which are analogues of parallel connection, while the total load:

Options for connecting loudspeaker lines to a broadcast amplifier are shown in Fig. 17.

Rice. 17 - Methods for connecting (matching) high-voltage lines to the output of a broadcast amplifier

Note: In the case of a star connection (connection), it is desirable to use a switch (relay module) included in the gap between the output of the broadcast amplifier and the loudspeaker lines.

The quality of car audio depends both on the class of the reproducing equipment and on the properties of the speakers. The latter are important not only to choose the right ones according to their characteristics, but also to place them in the passenger compartment in such a way as to use their capabilities to the maximum. To equip a car with high-quality sound, it is not necessary to turn to professionals. Connecting tweeters to the radio with your own hands is within the power of almost any driver.

Varieties of speakers for cars

Any speaker intended for use in a vehicle interior is one of the following types:

• broadband - manufacturers usually equip their cars with such speakers at the factory;
• coaxial (coaxial);
• component.

The single speaker of the broadband speaker reproduces the entire spectrum of audio frequencies. This is the cheapest solution, usually used in standard audio systems.

The single speaker of a full-range speaker is capable of reproducing a wide range of audio frequencies

The sound quality will improve if you divide the sound spectrum into several bands and entrust the reproduction of each of them to a separate emitter.

Several sound emitters are installed in a coaxial speaker in a single housing, which significantly improves sound quality

In a coaxial speaker in a single housing, usually on the same axis, several (2–5, more often 3) emitters are installed along with filters that select the sound frequencies that are optimal for each head.

Speakers of the component system are spaced apart in the space of the car

Component speaker systems have the widest range of high-quality reproduction. In them, as in coaxial speakers, the sound signal is reproduced by several emitters, but each is made as a separate speaker.

Two-component systems: tweeters and crossovers

Tweeters or tweeters are called high-frequency speakers, whose task is to reproduce the frequencies of the upper band of the sound spectrum. Regular tweeters are flat or slightly convex. Horn tweeters are slightly larger than conventional ones, as they are equipped with an element that forms a clear radiation pattern - a horn.

Tweeters or tweeters are called tweeters.

To select bands in component systems, crossovers are used, made in the form of separate blocks of audio frequency separation filters.

Crossovers can have from one to four stages: the more there are, the better the sound quality.

Component sound systems are the most difficult to install. However, the separation of the speakers in space provides the highest quality and surround sound.

The right choice of speakers and radio

First of all, specialized sound equipment is intended for installation in the car interior. Manufacturers of car speakers take into account not only the sound quality, but also difficult operating conditions: vibration, dust, temperature changes, and so on.

Is it possible to put household or pop speakers in a car

Computer and concert loudspeakers are designed for more forgiving conditions. In a car, they most likely will not live long.

In addition, computer speakers usually require not only a sound source, but also a separate power supply, without which they will not work, while car speakers are connected only to the output of an amplifier or radio.

As a rule, it is advisable to buy speakers where it is possible to assess the sound quality. Appearance does not play a special role, since in the car interior the speakers are usually covered with a decorative mesh or grille.

The choice of suitable speakers for a car consists in determining the basic requirements for them and comparing the technical characteristics of several models of the same price category.

Installation of car speakers

In consumer acoustic systems, the right and left speakers are usually at the same distance from the listener and approximately at the level of his head. It is unrealistic to meet such conditions in a car, therefore, when installing a component speaker, the need to achieve a possible approximation to the ideal comes to the fore.

Speaker placement options: where you can install the speakers

Experimentally, it was found that for frontal acoustics, the placement of speakers on the edges of the dashboard and the part of the front pillars adjacent to them is considered optimal. In this case, you need to ensure that the speakers are moved forward as far as possible.

Experts also advise placing different-frequency speakers related to the same channel in close proximity to each other. This will ensure the integrity and consistency of the sound. You can orient the speakers in opposite directions: one point at the driver, the other at the windshield of the car so that sound waves are reflected from it.

Unfortunately, large-sized speakers are difficult to place on the edges of the dashboard. Therefore, many car owners choose a compromise option.

It makes sense to place the woofers and midrange speakers in the lower front corner of the door, and the tweeters on the A-pillar or in the same corner of the dashboard. Such a scheme gives acceptable sound quality at a lower cost of time and money.

Such a creative option for placing speakers on a car door will be appreciated only by the most desperate music lovers.

Do-it-yourself replacement of standard loudspeakers

The least expensive way, both in terms of money and effort, to improve the sound in the car interior is to replace the standard broadband speakers with two- or three-way coaxial ones.

The standard place for "native" speakers is the lower front corner of the doors. For replacement, it is desirable to choose speakers of the same size as the regular ones. Larger speakers generally sound better, but you will need to widen the mounting hole in the door to fit them.

Installation Tools

You may need the following tool to replace speakers:

• jigsaw,
• electric drill,
• Phillips and flat screwdrivers
• soldering iron,
• pliers,
• car key set
• panel puller,
• file,
• insulating tape,
• plastic clamps for fastening wires.

Video: learning to connect speakers to a car radio on our own

Preparatory work: how to remove the trim

Before performing work, turn off the ignition and disconnect the negative cable from the battery. Then proceed like this:

How to remove the stock speaker and install a new one

Further work will require patience and care from you. Only compliance with the following sequence of actions guarantees the correct installation of the speakers.

How to connect speakers to the front or back door

It happens that the new column, coinciding with the old one in diameter, does not “sit down” on the standard podium (ring or ledge) or turns out to be thicker and starts to bulge too much. Sometimes the stand is completely missing. In this case, proceed as follows:

Video: how to install acoustics on a car

Location of component sound sources

The sound quality of coaxial speakers satisfies most motorists, but not all. The design disadvantage of coaxial sound is that high-frequency tweeters are placed in inaccessible places along with front speakers. To overcome this shortcoming, component systems with spaced speakers are used.

The features of high-frequency sound propagation require that, firstly, the tweeters be oriented towards the listener, and, secondly, there are no obstacles between them and the ear.

Due to the layout of the car interior, it is difficult to choose the ideal location for the location of the tweeters. The most acceptable compromise between price and quality is the placement of low and medium frequency speakers in their original place and the removal of high-frequency heads to the dashboard or to the front pillar.

Connecting tweeters

The procedure for mounting component speakers is as follows:

How to connect speakers in two-piece systems

Approximately 80% of motorists who install component sound systems are limited to installing additional tweeters. For some, this is not enough, since it is impossible to achieve the highest sound quality without “drawing” the lower frequencies of the sound spectrum on the verge of the limits of human hearing.

Obstacles in the path of propagation of vibrations of the lowest frequencies degrade the quality slightly. Therefore, huge subwoofers operating in the lower sound band are placed in the trunk or on the rear shelf of the passenger compartment.

Component car audio system can contain from 2 (including tweeter) speakers per channel up to 4, 6 or more

Thus, a component car audio system can contain from 2 (including tweeter) speakers per channel to 4, 6 or more. Practical implementation depends on the aesthetic requirements of the car owner, his desire to spend money and time to achieve them.

Scheme of channel-by-channel connection of AC components

All components of the audio system are interconnected by wires. Weak tweeters can be connected with almost any wire. Subwoofers are a completely different matter. With a power of 100 W, the speaker will need a current of about 8 A. In order not to be mistaken, it is best to use a specialized speaker cable with a wire cross section of at least 2.5 square meters. mm.

To connect the wires to each other and to the speakers, depending on the design features, use standard connectors, terminals or twisting with mandatory soldering

The wires for connecting the speakers are laid in inaccessible places, hiding under removable skins as far as possible from the rest of the bundles. In the door, sound lines are brought in through regular rubber accordion covers.

Following the above recommendations, any owner will be able to equip his car with good sound. How many speakers will be used, where exactly they will be installed - depends on the design features of the machine and the desire of its owner. And the secret of success lies in the availability of the necessary components and accuracy in the performance of work.

In this brief article, we will look at the main features of connecting broadcast amplifiers and loudspeakers. We will not describe the “Why”, we will not give connection calculation formulas, we will simply describe the “How”.

Broadcast equipment is fundamentally different from the technology that we are used to using at home or from professional concert or club systems. The main feature of broadcasting systems is the use of a matching transformer in the amplifier, which outputs a signal with a level of 100V into the line (in some cases it can be 30V, 240V, but we will consider these cases separately). Such a voltage allows (unlike home or professional amplifiers) to carry out long transmission lines up to hundreds of meters (possibly up to about 1 km, but subject to the selection of a suitable cable). Loudspeakers that are used in conjunction with broadcast amplifiers must also contain a step-down transformer and have an appropriate input voltage of 100V (respectively 30 or 240V in some cases). It is important to remember that the total power of the connected broadcasting loudspeakers should not exceed the power of the amplifier (unlike professional acoustic systems and amplifiers, where the reverse rule is recommended). Unlike professional equipment, in which connecting several speakers to one amplifier can cause certain difficulties (series-parallel connection), broadcast technology saves us from such difficulties. In the diagram below, you can see the general principle of connecting broadcast loudspeakers to ROXTON / / / / / amplifiers and the / / / series line. This connection scheme is quite relevant for equipment from other manufacturers.

The general wiring diagram for a 100V broadcast amplifier looks something like this:

Connecting 100V broadcast loudspeakers to the output of a 70V amplifier.

Most 100V amplifiers, in addition to the main 100V output in the loudspeaker line, also have a 70V output. When connecting speakers to this output, their output is halved, but the maximum number of speakers that can be connected can also be doubled. For example, no more than 3 10W loudspeakers per 100V output can be connected to a 30W amplifier. At 70V amplifier output, it is possible to connect 6 10W loudspeakers.

Connecting broadcast loudspeakers to multi-zone amplifiers.

Multi-zone amplifiers ROXTON / / / / / series, / / ​​series, as well as combined public address systems SX-240/480, allow you to connect several loops of acoustic systems to organize multi-zone broadcasting at the facility. Connection is made by separate loops to numbered pairs of terminals. These amplifiers also have a common output of 100V, 70V and 4 ohms, which are used when there is no need to divide the territory of the enterprise into separate broadcast zones. In this case, the corresponding common amplifier output is used.

Is it possible to connect broadcasting amplifiers of one manufacturer to loudspeakers of another manufacturer.

Of course you can. But it is important to take into account the moment that the output voltage of the amplifier and the input voltage of the speakers match. The most common technique in this market segment is 100V equipment (both amplifiers and loudspeakers), however 30V, 120V and 240V systems can be used. . If you connect 30V loudspeakers to a 100V amplifier, nothing good will happen and we categorically do not recommend doing this (although it should be noted that there were cases of such use of technology, but they require extreme accuracy and we will not talk about such experiments in order not to introduce tempted to do so). You can safely connect 100V loudspeakers to an amplifier with an output voltage of 30V, but the power loss (in fact, volume) will be completely unacceptable. A combination of 100V amplifiers and 120V speakers is acceptable, there will be some power loss. 120V amplifiers and 100V loudspeakers will work in principle, but we strongly advise against using such a circuit.

Connecting broadcast speakers.

We will focus here only on 100V loudspeaker wiring diagrams. You can see which amplifier outputs you need to use to connect broadcast acoustics in the diagrams above. As a rule, this is the "0" terminal (in some cases referred to as "COM") and the "100V" terminal.

In the picture below we see the nameplate of the loudspeaker (for example). On it, in addition to indicating the model, input voltage and rated power, there are three more inscriptions indicating the colors and purpose of the wires coming out of the loudspeaker.

1. BLUE: COM (i.e. the blue wire is common, it is always connected to the amplifier's "0" or "COM" terminal)
2. RED 20W
3. YELLOW: 10W

20W loudspeaker connection.

10W speaker connection.

In some cases, instead of wires, terminal blocks signed in the same way are used (for example, COM; 10 W; 5 W; 2.5 W), in this case, the connection is even simpler, we connect 0 (COM) on the amplifier with 0 (COM) on the speaker, and 100V amplifier terminal is connected to the selected power to which you want to connect the loudspeaker.

A very simple circuit is when only two wires come out of the loudspeaker (or there is one block with two terminals), and a signed switch is installed on the loudspeaker housing, which allows you to simply set the regulator to the desired position, to the desired power.

How to connect a loudspeaker if the power values ​​are not shown, but only the resistances of the loudspeaker taps are indicated.

Indeed, in some types of acoustic systems, the possible power connected to a specific outlet is not indicated. If everything is clear with the "common" tap ("COM" or "0"), then other taps, as in the picture below, can be indicated by different resistances.

In example 1 (Inter-M HS-20 horn loudspeaker, 20/10W) we see a common "COM" tap - a black wire (BLACK), as well as several resistances - 8 ohms (RED), 500 ohms (WHITE) and 1 kOhm (GREEN). The 8 ohm tap (RED) is intended only for connection to the low-resistance outputs of the amplifier and is rarely used in broadcast technology. If you see the designation of a 4 or 8 ohm speaker tap, then you can immediately forget about it, the use of this tap is possible only if the power amplifier itself is not broadcast and has only low-impedance outputs. (by the way, the same can be said about the outputs of 100V broadcast amplifiers 4-8-16 Ohm, these outputs are used in the opposite situation, when for one reason or another it is necessary to connect household, professional or any other acoustic systems with input impedance to the broadcast amplifier 4-8 ohm). There are two taps left - 500 Ohm (WHITE) and 1 kOhm (GREEN). The rule in this case is simple, the lower the resistance to which you connect, the more power the loudspeaker produces. In this example, we considered the HS-20 loudspeaker with a power of 20 and 10 watts. When connected to 500 ohms, the speaker will "play" at 20 watts, when connected to 1 kOhm, it will output 10 watts. There are formulas for calculating the ratio of resistance and power that we will not give in this article. You can just remember: the lower the resistance to which you connect the loudspeaker (8 ohms do not count at all!), the more power it will work.

In example 2, we have shown the designations of the CS-810 loudspeaker with a power of 10 and 5 watts. To connect the speaker system at full power (10 W), we connect the "COM" and 1 kOhm terminals, to connect the loudspeaker at half power (5 W), we use the "COM" and 2 kOhm terminals.

The same loudspeakers in the same transmission line can be connected to different powers. For example, part of the acoustics can be turned on at full power, part by half and part by a third. It is also possible to connect various types of acoustic systems (including various manufacturers) to one broadcast line. To calculate the load on a given broadcast line, simply add up all the connected power values ​​at each loudspeaker in the line.

How many loudspeakers can be connected to a broadcast amplifier.

The rule is simple. The total power of the acoustic systems should not exceed the power of the amplifier. It is even advisable to leave some margin. Therefore, when selecting a translational amplifier, it is necessary to take into account the possibility of expanding the system. If you bought 12 speakers with a power of 10 W each and a 120 W amplifier, then there is no reserve left for connecting additional acoustics (unless you just reconnect all the speakers to a part of the power).

We also note an important point, some multi-zone amplifiers do not allow, for example, to connect a power to a separate zone that exceeds the approximate value of the power of the amplifier itself, divided by the number of zones. For example, the JPA-1120A amplifier with a selector for 5 broadcast zones does not allow you to connect more than 25W to each broadcast zone. In this case, despite the fact that the total power of the loudspeakers can be significantly lower than the power of the amplifier itself, if it is necessary to connect (for example) a load of 50 W to a separate broadcast zone, you must either buy an amplifier that allows you to turn on such a load on a separate broadcast zone or various ways (sometimes costly, sometimes inconvenient) to solve this problem.

All ROXTON amplifiers that are presented on our website allow you to supply at least all the connected power to a separate broadcast zone, so the above nuance has nothing to do with them.

Is it possible to use 100V amplifier output and 8 ohm output at the same time.

No. It is forbidden.

Which cable to use to connect broadcast speakers and amplifiers.

A special speaker cable (which is used in professional audio) should not be used. As a rule, radio broadcasting systems are laid with an ordinary electric wire with a cross section of 0.75 mm and above (ShVVP-2 * 0.75, any PVS, etc.). The longer the transmission line, the larger the cross section of the cable should be used.

You can use this formula to calculate the cable section:

Minimum cross section = 0.08 * (line length) * (total loudspeaker power in the line) / 10,000

For 100V systems, the limit is about 1 km, and the cost of cable for laying a network over such distances can significantly increase the cost of the system itself. When building fire warning systems, it is advisable to use special fire-resistant cables, the brand of which will be suggested to you by the specialists of our company.

Wiring diagram for 100V loudspeakers for the background sound system and fire alarm in the premises

This article will talk about how loudspeakers for 100V lines are connected in sound systems.

Why did we choose speakers that operate in 100 volt mode? - Because this architecture has proven itself only from the good side in the market of sounding premises. The installation of such systems is so simple that even a person who has never dealt with similar systems can cope with this task. All that is needed to install and run the system is a minimal set of tools, or even improvised means, with which you can strip the wire and make holes.

So, if you have already decided on the required number of speakers, then let's move on to detailed instructions. Loudspeakers for 100 volt lines are connected to each other in parallel with a ShVVP 2x0.75 wire (two in the marking indicates the number of conductors in the wire, and 0.75 is their cross section; the color of the insulation in the conductors of such a wire is usually blue and brown). This wire can be found in any market and is inexpensive, making this architecture not only simple but also economical.

Loudspeakers for 100 volt lines come in different configurations. We will try to show how the most common ones are connected:

1. wall speaker has two terminals or clamps for 100V line input (red and black). We connect the red conductor to the red terminal, the blue one to the black one, as in the figure below:

If the loudspeaker is not the closing (final) one in the system, but is one of the links in the chain, then we connect the incoming and outgoing wire to it, having previously connected it by color (blue to blue, red to red). This is the essence of parallel connection:

2. Ceiling speakers with a fixed power value are connected similarly to wall-mounted ones.

3. Ceiling and horn loudspeakers with variable and fixed power parameter sometimes do not have terminals. Instead, from two to 7 wires of different colors are used. You can find the meanings of these colors in the connection manual that comes with the loudspeaker. Nevertheless, the principle is as follows - one of these transactions has the value COM or it is also called "0". Here we connect our blue conductor to this zero, and to one of the others (depending on the required power) - red.

Such an input group is uniquely present in spherical pendant loudspeakers.

Now let's go directly to the process of connecting the speakers to the amplifier. It doesn't matter what type of amplifier you choose: a mixing amplifier or a broadcast amplifier, connecting to them is equally simple. On the rear panel of the amplifier there are either terminals or clips for output to the speakers. You need to use the values ​​COM (or "0" it is sometimes called) and 100V. We connect the blue wire to the COM pin, which comes from the speakers, and the red wire to the 100V pin.

That's it, the background sound system or fire alarm system is over. Now you need to connect the sound source (DVD player, MP3 player, mobile phone, computer, etc.) to the amplifier using standard cables and enjoy high-quality playback of musical compositions. Inputs for sources on the amplifier are labeled Line-in or AUX and have standard "Tulip Mom" ​​connectors. Connectors are arranged in pairs and have color marks - red and white.