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Three-way and two-way acoustics: features, advantages, differences. Active full range speakers 2 way speaker

In a high-quality audio system, the main role is played by stereo or multi-channel acoustic systems.

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Thanks to them, electrical impulses are converted into sounds of the acoustic range. different frequency. For some, the sound of musical instruments is clean and as close as possible to the original, and for some, the voice of the vocalist, the actors of the film or the teacher from the training video courses comes first.

How important acoustic system?

It is the basis for the entire audio system.

It is preferable to start the selection of a suitable audio system with acoustics.

And for each, different equipment options will be a priority. The choice is influenced by such factors as the “sharpening” of such a system for those genres that the future owner likes and the price category.

For lovers of the most accurate sound, hi-fi speaker systems are suitable.
Despite the myths, not every expensive audio equipment shows these features.

In the case when the exclusive is in the first place, the audio system market provides fans of high-quality sound with Hi-End audio equipment.

Reference! High End is a marketing term that indicates the elitism of software and hardware to amplify the sound. Accordingly, the price of such audio systems does not scare only ardent music fans or lovers of non-serial sound equipment with a good financial condition.

Speaker types

There are several categories of speaker systems, each of which is able to satisfy certain customer needs. According to the basic differences, 5 basic classification groups are distinguished.

The principle of installation of equipment. Acoustic systems are divided into floor and bookshelf depending on the size. The former are preferred for large premises such as cinemas. Using them at home for a TV or computer is unprofitable. It is best to use shelf speakers.
Number of speakers. Otherwise, this is called division by the number of sound bands. The manufacturer may include from 1 to 7 speakers. The most budget-friendly option is 3 speakers, where one band is responsible for low frequencies, another for mids and a third for highs.

The presence or absence of a sound amplifier in the speakers. In the first case, they are called active, in the second - passive. Passive options are much more common. They are preferable for audiophiles due to the crossover filter and, accordingly, higher sound quality due to frequency separation.
By design, speakers are divided into planar, dynamic, electrostatic and other types, and in some cases the equipment does not fall into any category.
Decoration. Speakers can have a closed or open case, a phase reflex is a good addition - a pipe in a speaker tuned to a certain frequency and amplifying sounds within it. Thanks to this hole, lower frequencies are reproduced than with conventional equipment. If the pipe is bent inside the body, increasing its length, power and range of reproducible low frequencies, you get speakers with an acoustic labyrinth. They are more expensive and require more precision in manufacturing.

Areas of use of acoustic systems

The first and main area of application is home use.

This includes the need for quality sound for greater immersion in video games, the power and intensity of sound for watching TV, the clarity and closeness to the original sound for music lovers of various genres.

Fans of high-quality music in the car are advised to purchase multi-band audio systems.

Moreover, for better sound, high-frequency and mid-frequency elements of the Car-system are located in the front of the car. woofers the rear is often relegated to the car.

Concert versions of acoustic systems are designed not only to provide sound access to any point of a large room or hall, but also to satisfy the requirements of many listeners for sound quality. The most common live audio kits include monitors for nuanced sound, front speakers for direct, high-density sound, and center speakers for vocals.

2-way acoustics

A separate category is recording studios. They prefer studio monitors that are able to reproduce the sound with all its pluses and minuses, which ultimately contributes to the creation of a track that is cleaner and more reliable in its sound.

Regardless of where the acoustic system will be used, it is recommended to preliminarily determine the criteria by which the selection of suitable equipment will take place.

With their help, you will be able to get equipment that can bring you as close as possible to the sound of your dreams.

PRO 6020 : Hi-End 2-way component audio system with a molded basket and a diffuser made of multilayer unpressed cellulose with the addition of cotton fiber Acoustic two-way component system PRO 6020 (165mm) was created by acoustic professionals for professionals and lovers of high-quality music reproduction. Every detail, every component of the system has been carefully selected. Much attention was paid even to such trifles, which, at first glance, are not directly related to high-quality sound reproduction. The audio system conveys a three-dimensional space, giving the listener the feeling of being at a musical event. Fully controlled uncolored sound, powerful bass impact, amazing dynamics, strictly conveying the spatial characteristics of the recording - this is how you can convey the sensations of the listener. Excellent electro-acoustic parameters and a smooth, wide frequency response make it the best choice in very dynamic installations. As a result of numerous laboratory tests and checks, unpressed cellulose with the addition of cotton fiber was chosen as the material for the manufacture of the woofer cone. This material has unique properties. It is very light and strong, but its main advantage is its excellent internal damping, which is so necessary for accurate sound reproduction. This material is used to make speaker cones in high-end home audio systems. Stable operation of the moving system is ensured by a cast anti-vibration basket with anti-resonance coating, a powerful magnet, a multilayer voice coil made of copper-plated aluminum wire, a butyl rubber suspension and a centering washer of a special design. Terminals with gold-plated contacts ensure a reliable connection of the speaker contacts with the connecting wires. Precise and easy reproduction of high frequencies is ensured by a 1 (25.4mm) inch tweeter with a neodymium magnet and a silk dome. The use of an aluminum copper-plated coil led to a reduction in the mass of the moving system, which made it possible to confidently reproduce the highest frequencies of the audio range. At the same time, the speaker is able to cope with high power, due to the better conductivity of the copper-plated wire and the presence of a cooling ferromagnetic fluid in the magnetic gap. Its swivel design allows you to precisely position the speaker in relation to the listener and provide a better match between the woofer and tweeter. High-quality elements are used in the two-way crossover. The air-core crossover coils are wound with thick copper wire to reduce losses. The crossover frequency (2500Hz; 18dB/Oct) is optimized for audio performance in any type of car. It is possible to fine-tune the volume level of the tweeter (-3dB/0/+3dB). Another feature of the crossover is the possibility of its channel-by-channel connection, namely, separate tweeter and midbass (the so-called "bi-amping" scheme). To do this, you just need to cut a special technological loop in the crossover circuit. The "Absolute Sound" line is specially designed for lovers of high-quality sound and is able to satisfy the requirements of the most demanding listener. This line combines the PRO 693, PRO 6020 and PRO 62D models. Acoustics line "Absolute Sound" is designed to work with external amplifiers in a wide range of capacities.

2-way acoustics in a car

The acoustic two-way system has long been very popular with motorists who appreciate good sound. Today, three-way acoustics is a clear competitor to this acoustics, but the supporters of the former system still respect it and are not going to change it for anything.
In what way a two-way speaker system is better and why it is so loved, we will learn from this article, where, in addition, instructions will be given for quickly installing it in a car.

Advantages of two-way acoustics

As you know, all types of strip acoustics are divided into special classes. In this case, we are talking about the component and .

coaxial acoustics

It implies the presence of two heads installed in the speaker housing. Advantages - low cost and ease of installation.

Component acoustics

Two speakers are combined into one complete system that reproduces low and high frequencies. The cost of such a system is much higher, which is understandable.

Front and rear speakers

In a car, as you know, it is still customary to install speakers depending on the direction of the sound.

- this, in principle, is the installation of speakers in regular places, that is, in the front doors. Everything would be fine and there would be no problems if the regular places were made in accordance with high-quality speakers.
But the fact is that on almost any car, these very places intended by the manufacturer for installing speakers are very small and designed for small speakers.
Front acoustics takes on the most important function - creating the right sound stage in the car. At the same time, its installation involves the use of special door linings, followed by a strong fastening of the speakers.
Front acoustics usually involves installing speakers in the upper parts of the front doors.

To achieve the best sound effect, 2-way acoustics should be mounted so that its elements are as close to each other as possible. It implies the installation of a woofer in the door, and a tweeter on the rack or dashboard of the car.

Advantages of front acoustics:

Installation will be quick and easy.
In the case of a 2-way system, there will be practically no difficulties during installation.
On the other hand, installation in a door means that the speaker does not have a housing, which can negatively affect the sound quality. In this regard, craftsmen come up with various and original ones that enhance the sound effect from the speakers.

As mentioned above, the main thing in a car is rear acoustics. As for this system, it will serve as an additional sound effect.
So:

The use of rear acoustics is justified, because the speakers in this case improve the overall background sound, making the sound picture much deeper.
2-way acoustics sound better, of course, in the front, but in the back in the trunk or on the speaker shelf, its mids will sound good.
Installing the rear speakers also involves making a special acoustic shelf that contributes to the best sound of the speakers.

Installation of 2-way acoustics

So, as it became clear, a complete installation of 2-way acoustics in a car involves using it both in front and behind.

Front doors:

Note. For installation in the front doors, it is desirable to use 16 cm speakers.

We purchase or make our own podiums for speakers.

Note. It is worth noting that the podiums themselves are unlikely to provide the speakers with strength. Therefore, a board is made separately for the podiums or special linings made of chipboard or plywood are placed under them.

We are finalizing the doors, increasing the dimensions for installing 16 cm speakers. Also at this stage, a strong support is placed, which must be firmly screwed to the metal part of the door.

We create an acoustic volume by sealing the door openings with masking tape. We paste over the adhesive tape with fiberglass cloth, which, in turn, is impregnated with epoxy glue.
If the podiums are made independently, then you will first need to cut out rings with 4 ears from plywood. These same ears will be needed to mount the podium on the door.
Then we make 2 intermediate rings for each podium and assemble everything together, using spacers as well.
We fasten the podiums firmly to the door.
We glue the door with vibroplast.

Note. The crossover can be installed next to the door handle, because in this place it will be quite free to be (depending on the car model).

The instructions above will help you not to make mistakes when choosing and installing this speaker system with your own hands. During the installation process, it is recommended to study the photo and video materials.
As you know, the price of installing audio systems in a car is always high for professionals, so there is a reason to learn how to do everything yourself.

Making loudspeakers with your own hands - this is where many begin their passion for a difficult, but very interesting thing - the technique of sound reproduction. Economic considerations often become the initial motivation: the prices for branded electro-acoustics are overstated, not excessively - ugly arrogantly. If the sworn audiophiles, who do not skimp on rare tubes for amplifiers and flat silver wire for winding audio transformers, complain on the forums that the prices for acoustics and speakers for it are systematically inflated, then the problem is really serious. Do you want speakers for the house for 1 million rubles. pair? Please, there are more expensive ones. So The materials in this article are designed primarily for the very, very beginners: they need to quickly, simply and inexpensively make sure that the creation of their own hands, for which everything took dozens of times less money than for a “cool” brand, can “sing” no worse, or at least comparable. But probably, some of the foregoing will be a revelation for the masters of amateur electroacoustics- if it is honored by reading them.

Speaker or speaker?

Sound column (KZ, sound column) is one of the types of acoustic design of electrodynamic loudspeaker heads (GG, speakers), designed for technical and information sounding of large public spaces. In general, the acoustic system (AS) consists of a primary sound emitter (FROM) and its acoustic design, which provides the required sound quality. Home speakers are for the most part similar in appearance to loudspeakers, which is why they are nicknamed. Electroacoustic systems (EAS) also include an electrical part: wires, terminals, crossover filters, built-in audio frequency power amplifiers (UMZCH, in active speakers), computing devices (in speakers with digital channel filtering), etc. Acoustic design of household speakers is usually located in the body, which is why they look like more or less elongated columns.

Acoustics and electronics

The acoustics of an ideal speaker is excited over the entire audible frequency range of 20-20,000 Hz with one broadband primary IZ. Electroacoustics is slowly but surely moving towards the ideal, however, the best results are still shown by speakers with frequency separation into channels (bands) of LF (20-300 Hz, low frequencies, bass), MF (300-5000 Hz, medium) and HF (5000 -20,000 Hz, treble, treble) or LF-MF and HF. The first, of course, are called 3-way, and the second - 2-way. It is best to start mastering electroacoustics with 2-way speakers: they allow you to get sound quality up to high Hi-Fi (see below) inclusive at home without unnecessary costs and difficulties. The sound signal from the UMZCH or, in active speakers, low-power from the primary source (player, computer sound card, tuner, etc.) is distributed over the frequency channels by crossover filters; this is called channel defiltering, like crossover filters themselves.

The remainder of the article focuses primarily on how to make speakers that provide good acoustics. The electronic part of electroacoustics is a subject of special serious discussion, and not just one. Here it is only necessary to note that, firstly, at first it is not necessary to take on digital filtering that is close to ideal, but complex and expensive, but to apply passive filtering on inductive-capacitive filters. For a 2-way speaker, you need only one plug of low-pass/high-pass crossover filters (LPF/HPF).

There are special programs for the calculation of separation ladder filters AC, for example. JBL Speaker Shop. However, at home, the individual tuning of each plug for a specific instance of the speakers, firstly, does not affect production costs in mass production. Secondly, the replacement of the GG in the AU is required only in exceptional cases. This means that the filtering of the AC frequency channels can be approached unconventionally:

The frequency of the section LF-MF m HF is taken not lower than 6 kHz, otherwise you will not get a sufficiently uniform amplitude-frequency characteristic (AFC) of the entire speaker in the midrange region, which is very bad, see below. In addition, at a high crossover frequency, the filter is inexpensive and compact;
The prototypes for calculating the filter are links and half links of filters of type K, because their phase-frequency characteristics (PFC) are absolutely linear. Without observing this condition, the frequency response in the crossover frequency region will turn out to be significantly uneven and overtones will appear in the sound;
To obtain the initial data for the calculation, it is necessary to measure the impedance (impedance) of the LF-MF and HF GG at the crossover frequency. The GG 4 or 8 Ohms indicated in the passport are their active resistance at direct current, and the impedance at the crossover frequency will be greater. The impedance is measured quite simply: the GG is connected to an audio frequency generator (GZCH), tuned to the crossover frequency, with an output of at least 10 V to a load of 600 Ohms through a resistor of obviously high resistance, for example. 1 kOhm You can use low-power GZCH and UMZCH high fidelity. The impedance is determined by the ratio of the audio frequency (AF) voltages across the resistor and GG;
The impedance of the LF-MF link (GG, heads) is taken as the characteristic impedance ρn of the low-pass filter (LPF), and the impedance of the HF head is taken as ρv of the high-pass filter (HPF). The fact that they are different - well, the fool is with them, the output impedance of the UMZCH, "rocking" the speakers, is negligible compared to this and that;
From the side of the UMZCH, reflective-type low-pass and high-pass filters are installed so as not to overload the amplifier and not take power from the associated speaker channel. To GG, on the contrary, they turn to absorbing links, that the return from the filter did not give overtones. Thus, low-pass and high-pass speakers will have at least a link with a half link;
The attenuation of the LPF and HPF at the crossover frequency is taken equal to 3 dB (1.41 times), because the steepness of the slopes of K-filters is small and uniform. Not 6 dB, as it may seem, because. filters are calculated by voltage, and the power supplied to the GG depends on it squarely;
Adjusting the filter comes down to "muting" a too loud channel. The loudness of the channels at the crossover frequency is measured using a computer microphone, turning off HF and LF-MF in turn. The degree of "muting" is defined as the square root of the ratio of the loudness of the channels;
The excessive volume of the channel is removed with a pair of resistors: the quenching one by fractions or units of ohms is connected in series with the GG, and in parallel with both of them - equalizing the greater resistance so that the impedance of the GG with the resistors remains unchanged.

Explanations to the methodology

A technically knowledgeable reader may have a question: does the filter for the complex load work for you? Yes, and in this case - no big deal. The phase response of K-filters is linear, as mentioned, and Hi-Fi UMZCH is almost an ideal voltage source: its output impedance Rout is units and tens of mΩ. Under such conditions, the “reflection” from the GG reactance will partially attenuate in the output absorbing link / half-link of the filter, but for the most part will leak back to the UMZCH output, where it will disappear without a trace. In fact, nothing will pass into the associated channel, because ρ of its filter is many times greater than Rout. There is one danger here: if the impedance of the GG and ρ are different, then power circulation will begin in the filter output - GG circuit, which will make the bass become dull, “flat”, attacks on the midrange will be prolonged, and the top will be sharp, with a whistle. Therefore, the impedance of the GG and ρ must be adjusted exactly, and in the event of a replacement of the GG, the channel will have to be tuned again.

Note: do not try to filter active speakers with analog active filters on operational amplifiers (op-amps). It is impossible to achieve the linearity of their phase characteristics in a wide frequency range, therefore, for example, analog active filters have not really taken root in telecommunication technology.

What is hifi

Hi-Fi, as you know, is short for High Fidelity - high fidelity (sound reproduction). The concept of Hi-Fi was initially accepted as vague and not subject to standardization, but its informal division into classes gradually developed; the numbers in the list indicate, respectively, the range of reproducible frequencies (operating range), the maximum allowable coefficient of non-linear distortion (THD) at rated power (see below), the minimum allowable dynamic range relative to the room's own noise (dynamics, the ratio of maximum volume to minimum), the maximum allowable uneven frequency response in the midrange and its blockage (decline) at the edges of the operating range:

Absolute or full - 20-20,000 Hz, 0.03% (-70 dB), 90 dB (31,600 times), 1 dB (1.12 times), 2 dB (1.25 times).
High or heavy - 31.5-18,000 Hz, 0.1% (-60 dB), 75 dB (5600 times), 2 dB, 3 dB (1.41 times).
Medium or basic - 40-16,000 Hz, 0.3% (-50 dB), 66 dB (2000 times), 3 dB, 6 dB (2 times).
Initial - 63-12500 Hz, 1% (-40 dB), 60 dB (1000 times), 6 dB, 12 dB (4 times).

It is curious that high, basic and initial Hi-Fi approximately correspond to the highest, first and second classes of household electroacoustics according to the USSR system. The concept of absolute Hi-Fi arose with the advent of condenser, film-panel (isodynamic and electrostatic), jet and plasma sound emitters. Heavy (Heavy) high Hi-Fi called the Anglo-Saxons, because. High High Fidelity in English is like butter.

What kind of hi-fi do you need?

Home acoustics for a modern apartment or house with good sound insulation must meet the conditions for basic Hi-Fi. High there, of course, will not sound worse, but it will cost a lot more. In block Khrushchev or Brezhnevka, no matter how you isolate them, only professional experts distinguish between initial and basic Hi-Fi. The grounds for such a coarsening of the requirements for home acoustics are as follows.

Firstly, the full range of sound frequencies is heard by literally a few people from all over humanity. People gifted with a particularly delicate ear for music, such as Mozart, Tchaikovsky, J. Gershwin, hear high Hi-Fi. Experienced professional musicians in a concert hall confidently perceive basic Hi-Fi, and 98% of ordinary listeners in a sound chamber almost never distinguish between initial and basic in frequency.

Secondly, in the most audible region of the midrange, a person in terms of dynamics distinguishes sounds in the range of 140 dB, counting from the audibility threshold of 0 dB, equal to the intensity of the sound flux of 1 pW per square meter. m, see fig. curves of equal loudness on the right. A sound louder than 140 dB is already pain, and then - damage to the hearing organs and concussion. An expanded symphony orchestra on the most powerful fortissimo produces sound dynamics up to 90 dB, and in the halls of the Grand Opera, Milan, Paris, Vienna Opera Houses and the Metropolitan Opera in New York, it is able to "accelerate" up to 110 dB; such is the dynamic range of leading jazz bands with symphonic accompaniment. This is the limit of perception, louder than which the sound turns into still tolerable, but already meaningless noise.

Note: rock bands can play louder than 140 dB, which Elton John, Freddie Mercury and the Rolling Stones were fond of when they were young. But the dynamics of rock does not exceed 85 dB, because rock musicians cannot play the most delicate pianissimo with all their desire - the equipment does not allow, and there is no rock "in spirit". As for pop music of any kind and movie soundtracks, this is not a topic at all - their dynamic range is already compressed to 66, 60 and even 44 dB during recording, so that you can listen to anything.

Thirdly, natural noises in the quietest living room of a country house in the outskirts of civilization - 20-26 dB. The sanitary norm of noise in the reading room of the library is 32 dB, and the rustle of leaves in the fresh wind is 40-45 dB. From this it is clear that the high Hi-Fi speakers of 75 dB are more than enough for meaningful listening in the home; the dynamics of modern UMZCH of the average level, as a rule, is not worse than 80 dB. In a city apartment, it is almost impossible to recognize basic and high Hi-Fi by the dynamics.

Note: in a room noisier than 26 dB, the frequency range of your favorite Hi-Fi can be narrowed down to the limit. class, because the effect of masking affects - against the background of indistinct noises, the sensitivity of the ear in frequency decreases.

But in order for Hi-Fi to be high-fi, and not “happiness” for “beloved” neighbors and harm to the health of the owner, it is necessary to ensure even the smallest possible sound distortion, correct reproduction of low frequencies, smooth frequency response in the midrange region, and determine what is necessary for scoring this room AC electric power. As a rule, there are no problems with HF, because. their SOI "leave" in the inaudible ultrasonic region; you just need to put a good HF head in the speakers. It is enough to note here that if you prefer classics and jazz, it is better to take the HF GG with a cone for a power of 0.2-0.3 from that of the low-frequency channel, for example. 3GDV-1-8 (2GD-36 in the old way) and the like. If you are “rushing” from hard tops, then the HF GG with a dome emitter (see below) with a power of 0.3-0.5 of the power of the low-frequency link will be optimal; drumming with brushes is naturally reproduced only by dome tweeters. However, a good dome tweeter is suitable for any kind of music.

distortion

Sound distortions are possible linear (LI) and non-linear (NI). Linear distortion is, simply, a discrepancy between the average volume level and the listening conditions, for which any UMZCH has a volume control. Expensive 3-way speakers for high Hi-Fi (for example, the Soviet AC-30, aka S-90) are often also equipped with power attenuators for midrange and treble in order to more accurately adjust the frequency response of the speaker to the acoustics of the room.

As for NI, they, as they say, are innumerable and new ones are constantly being discovered. The presence of NI in the audio path is expressed in the fact that the shape of the output signal (which the sound is already in the air) is not completely identical to the shape of the original signal from the primary source. Most of all they spoil the purity, "transparency" and "juiciness" of the sound of the trace. NI:

Harmonic - overtones (harmonics) that are multiples of the fundamental frequency of the reproduced sound. Manifested as excessively roaring bass, sharp and hard midrange and treble;
Intermodulation (combination) - the sums and differences of the frequencies of the components of the spectrum of the original signal. Strong combinational NIs are heard as wheezing, and weak, but spoiling the sound, can only be recognized in the laboratory by multi-signal or statistical methods on test phonograms. By ear, the sound seems to be clear, but somehow not so;
Transient - "jitter" of the output signal form with sharp rises / falls of the original. They manifest themselves with short wheezing and sobbing, but irregularly, at volume jumps;
Resonant (overtones) - ringing, rattling, mumbling;
Frontal (distortion of the sound attack) - delaying or, conversely, forcing sharp changes in the overall volume. Almost always occur together with transitional;
Noise - hum, rustle, hiss;
Irregular (sporadic) - clicks, cods;
Interference (AI or IFI, not to be confused with intermodulation). They are characteristic specifically for the AU, in the UMZCH IFI do not occur. Very harmful, because. perfectly audible and unremovable without a major alteration of the speakers. See below for more information on FFI.

Note:"wheezing" and other figurative descriptions of distortion hereinafter are given from the point of view of Hi-Fi, i.e. as already heard by sophisticated listeners. And, for example, speech speakers are designed for SOI at a nominal power of 6% (in China - by 10%) and 1

In addition to interference, speakers can give predominantly NI according to paragraphs. 1, 3, 4 and 5; clicks and cods are possible here as a result of poor-quality workmanship. They fight with transient and frontal NIs in speakers by selecting suitable HGs (see below) and acoustic design for them. Ways to avoid overtones - the rational design of the speaker cabinet and the right choice of material for it, also see below.

It is necessary to linger on harmonic NI in the AC, because they are fundamentally different from those in semiconductor UMZCH and are similar to the harmonic NI tube ULF (low-frequency amplifiers, the old name is UMZCH). A transistor is a quantum device, and its transfer characteristics are not fundamentally expressed by analytical functions. The consequence is that it is impossible to accurately calculate all the harmonics of the transistor UMZCH, and their spectrum stretches to the 15th and higher components. Also, in the spectrum of transistor UMZCH, the proportion of combinational components is large.

The only way to deal with all this mess is to hide the NI deeper under the amplifier's own noise, which, in turn, should be many times lower than the natural noise of the room. I must say that modern circuitry copes with this task quite successfully: according to the current ideas, UMZCH with 1% THD and -66 dB of noise is "no", and with 0.06% THD and -80 dB of noise is pretty mediocre.

With harmonic NI speaker speakers, the situation is different. Their spectrum, firstly, like that of tube ULFs, is pure - only overtones without a noticeable admixture of combination frequencies. Secondly, the AC harmonics can be traced, just like in lamps, not higher than the 4th. Such an NI spectrum does not noticeably spoil the sound even with a SOI of 0.5-1%, which is confirmed by expert estimates, and the reason for the “dirty” and “sluggish” sound of home-made speakers lies most often in the poor frequency response in the midrange. For your information, if the trumpeter did not properly clean the instrument before the concert and during the game does not splash saliva out of the embouchure in a timely manner, then the THD of, say, a trombone can grow up to 2-3%. And nothing, they play, the audience likes it.

The conclusion from here follows a very important and favorable one: the frequency range and intrinsic harmonics of the NI speakers are not parameters that are critical for the quality of the sound it creates. The sound of speakers with 1% and even 1.5% harmonic NI experts can be attributed to the basic, and even high Hi-Fi, if appropriate. conditions for the dynamics and smoothness of the frequency response.

Interference

IFI is the result of the convergence of sound waves from nearby sources in phase or in antiphase. The result is bursts, up to pain in the ears, or dips of almost zero volume at certain frequencies. At one time, the firstborn of the Soviet Hi-Fi 10MAC-1 (not 1M!) Was urgently discontinued after the musicians discovered that this speaker did not reproduce the second octave at all (as far as I remember). At the factory, the prototype was “chased” in a sound meter using the three-signal method, antediluvian even then, and there was no position of an expert with an ear for music in the staff list. One of the paradoxes of developed socialism.

The probability of occurrence of IFI increases sharply with an increase in frequency and, accordingly, a decrease in the wavelength of sound, since for this, the distance between the centers of the emitters must be a multiple of half the wavelength of the reproducible frequency. On MF and HF, the latter changes from units of decimeters to millimeters, therefore, it is impossible to put two or several MF and HF GG in the AU in any way - then IFI cannot be avoided, because. the distances between the HG centers will be of the same order. In general, the golden rule of electroacoustics is one transducer per band, and the brilliant one is one broadband GG for the entire frequency range.

The wavelength of the LF is meters, which is much larger than not only the distance between the GG, but also the size of the speakers. Therefore, manufacturers and experienced amateurs often increase the power of the speakers and improve the bass by pairing or quadrupling (quadruplet) LF GH. However, a beginner should not do this: internal interference of reflected waves “walking” with the speaker itself may occur. To the ear, it manifests itself as resonant NI: it bubbling, gundosing, rattling, why is not clear. So follow the precious rules so as not to sort through the whole speaker over and over again to no avail.

Note: it is impossible to put an odd number of identical GGs in the AS in any case - the FFI is then guaranteed 100%

MF

Novice amateurs pay little attention to the reproduction of medium frequencies - they, they say, any speaker will “sing” - but in vain. MFs are heard best of all, they also account for the original ("correct") harmonics of the basis of everything - basses. The uneven frequency response of the speakers in the midrange is capable of giving combination NI that spoil the sound very much, tk. the spectrum of any phonogram "floats" over the frequency range. Especially - if the speakers use efficient and inexpensive speakers with a short cone stroke, see below. Subjectively, when listening, experts unambiguously prefer speakers with a frequency response to a midrange that smoothly changes over the frequency range within 10 dB over one that has 3 dips or "bumps" of 6 dB each. Therefore, when designing and making speakers, you need to carefully check at every step: will this frequency response not “hunchback” on the midrange?

Note, speaking of bass: rock joke. So, a young promising group broke through to a prestigious festival. In half an hour they will go out, and they are already backstage, worrying, waiting, but the bassist went on a spree somewhere. 10 minutes before the exit - it is not there, 5 minutes - also not. The exit is waving, but the bassist is still missing. What to do? Well, let's play without bass. Absence is an instant collapse of a career forever. They played without bass, it's clear how. They wander to the service exit, spit, swear. Look - a bassist, drunk, with two heifers. They to him - oh you, goat, do you even understand how you threw us?! Where have you been?! - Yes, I decided to listen in the hall. - And what did you hear there? “Dudes, no bass—sucks!”

LF

Bass in music is like the foundation of a house. And in the same way, the "zero cycle" of electroacoustics is the most difficult, complex and responsible. The audibility of sound depends on the energy flux of the sound wave, which depends on the frequency squared. Therefore, the bass is the worst heard, see fig. with curves of equal loudness. To "pump" energy into the bass, you need powerful speakers and UMZCH; in reality, more than half of the power of the amplifier is spent on bass. But at high powers, the probability of the occurrence of NI increases, the strongest and, of course, the audible components of the spectrum of which from the bass will fall exactly on the best audible mids.

"Pumping" of LFs is further complicated by the fact that the dimensions of the GG and the entire AS are small compared to the wavelengths of LFs. Any source of sound gives it energy the better, the larger its size relative to the wavelength of the sound wave. The acoustic efficiency of the speakers at low frequencies is units and fractions of a percent. Therefore, most of the work and troubles in creating an AU comes down to making it better reproduce low frequencies. But let us remind you once again: do not forget to control the purity of the midrange as often as possible! Actually, the creation of the low-frequency tract of the speaker is reduced to:

Determination of the required electrical power of LF GG.
Selecting a LF GH suitable for the given listening conditions.
The choice of the optimal acoustic design for the selected LF GG (hull design).
Its correct manufacture in a suitable material.

Power

Sound return in dB (characteristic sensitivity) is indicated in the speaker's passport. It is measured in a sound chamber 1 m from the center of the GG with a measuring microphone located strictly along its axis. The GG is placed on a sound-measuring shield (standard acoustic screen, see the figure on the right) and an electric power of 1 W is supplied (0.1 W for a GG with a power of less than 3 W) at a frequency of 1000 Hz (200 Hz, 5000 Hz). Theoretically, according to these data, the class of the desired Hi-Fi and the parameters of the room / listening area (local acoustics), it is possible to calculate the required electrical power of the GG. But in fact, accounting for local acoustics is so complicated and ambiguous that experts rarely fool around with it.

Note: The GG for measurements is shifted from the center of the screen in order to avoid the interference of sound waves from the front and rear radiating surfaces. The screen material is usually a cake of 5 layers of non-skinned 3-layer pine plywood on casein glue 3 mm thick and 4 gaskets between them made of natural felt 2 mm thick. Everything is glued together with casein or PVA.

It is much easier to go from the existing conditions to the technical sounding of low-noise rooms, adjusted for the dynamics and frequency range of Hi-Fi, especially since the results obtained in this case are in better agreement with known empirical data and expert assessments. Then for the initial Hi-Fi it is necessary, with a ceiling height of up to 3.5 m, 0.25 W of the nominal (long-term) electric power of the GG per 1 sq. m floor area, for basic Hi-Fi - 0.4 W/sq. m, and for high - 1.15 W / sq. m.

The next step is to take into account real listening conditions. Hundred-watt speakers capable of operating at microwatt levels are outrageously expensive, on the one hand. On the other hand, if a separate room, equipped as a sound-measuring chamber, is not allocated for listening, then their “microwhispers” on the quietest pianissimo in any living room will not be heard (see above about natural noise levels). Therefore, we increase the obtained values by a factor of two or three in order to “tear off” what is being heard from the noise background. We get for the initial Hi-Fi from 0.5 W / sq. m, base from 0.8 W/sq. m and for high from 2.25 W / sq. m.

Further, since we need high-fi, and not just speech intelligibility, we need to move from nominal power to peak (musical) power. The "juice" of the sound depends primarily on the dynamics of its volume. SOI GG at loudness peaks should not exceed its values for Hi-Fi by a class below the chosen one; for the initial Hi-Fi, we take 3% SOI at the peak. In sales specifications for Hi-Fi speakers, peak power is indicated as more significant. According to the Soviet-Russian methodology, the peak power is 3.33 long-term; according to the methods of Western firms, "music" is equal to 5-8 denominations, but - stop for now!

Note: Chinese, Taiwanese, Indian and Korean methods are ignored. They for basic (!) Hi-Fi at the peak take a telephone THD of 6%. But the Philippines, Indonesia and Australia measure their dynamics correctly.

The fact is that without exception, all Western manufacturers of Hi-Fi GG shamelessly overestimate the peak power of their products. It would be better if they promoted their SOI and the evenness of the frequency response, here they really have something to be proud of. Yes, but an ordinary foreign inhabitant will not understand such difficulties, and if “180W”, “250W”, “320W” are smeared on the speaker, this is really cool. In reality, running the speakers "from there" in the sound meter gives them peaks of 3.2-3.7 ratings. Which is quite understandable, because. this ratio is justified physiologically, i.e. structure of our ears. Conclusion - aiming at the Western GG, go to the company website, look for the rated power there and multiply by 3.33.

Note 9, about the designations of the peak and the nominal value: in Russia, according to the old system, the numbers in front of the letters in the designation of the speaker indicated its rated power, and now they give the peak power. But at the same time, the root with the designation suffix was also changed. Therefore, the same speaker can be designated in completely different ways, see examples below. Look for the truth from reference sources or on Yandex. There, no matter what designation you enter, the results will contain a new one, and the old one next to it in brackets.

In the end, we get for a room up to 12 square meters. m peak for the initial Hi-Fi at 15 W, the base at 30 W and the high at 55 W. These are the smallest allowed values; take GG twice or three times more powerful, it will be better, unless you listen to symphonic classics and very serious jazz. For them, it is desirable to limit the power to 1.2-1.5 of the minimum, otherwise wheezing is possible at the peaks of volume.

You can get by even easier by focusing on proven prototypes. For initial Hi-Fi in a room up to 20 sq. m suitable GG 10GD-36K (10GDSH-1 in the old way), for high - 100GDSH-47-16. They do not need filtering, these are broadband GGs. With basic Hi-Fi it is more difficult, a suitable broadband for it is not found, you need to make a 2-way speaker. Here, at first, the optimal solution is to repeat the electrical part of the old Soviet AS S-30B. These speakers have been working properly and very well for decades in apartments, cafes and just on the street. Shabby utterly, but the sound is kept.

S-30B filtering scheme (without overload indication) is shown in fig. left. Minor refinement was made to reduce losses in the coils and the possibility of fitting to various LF GG; if desired, taps from L1 can be made more often, within 1/3 of the total number of turns w, counting from the right end of L1 according to the scheme, the fit will be more accurate. On the right - instructions and formulas for self-calculation and manufacture of filter coils. Precision precision details are not required for this filtering; +/-10% deviations in the inductance of the coils also do not noticeably affect the sound. It is advisable to bring the R2 engine to the back wall for quick adjustment of the frequency response to the room. The circuit is not very sensitive to the impedance of the speakers (in contrast to the filtering on K-filters), therefore, instead of the indicated ones, other HGs can be used that are suitable in terms of power and resistance. One condition: the highest reproducible frequency (HF) of the LF GH at the level of -20 dB must not be lower than 7 kHz, and the lowest reproducible frequency (LF) of the HF GH at the same level must not be higher than 3 kHz. By shifting-pushing L1 and L2, you can somewhat correct the frequency response in the region of the crossover frequency (5 kHz), without resorting to such complexities as the Zobel filter, which can also increase transient distortion. Capacitors - film with PET or fluoroplastic insulation and sprayed plates (MKP) K78 or K73-16; in extreme cases - K73-11. Resistors - metal film (MOX). Wires - audio from oxygen-free copper with a cross section of 2.5 square meters. mm. Mounting - soldering only. On fig. the right side shows what the original S-30B filtering looks like (with the overload indication circuit), and in fig. below on the left is a 2-way filtering scheme popular abroad without magnetic coupling between the coils (why their polarity is not indicated). On the right there, just in case, is a 3-way filtering of the Soviet AC S-90 (35AC-212).

About wires

Special audio wires are not a product of mass psychosis and not a marketing gimmick. The effect discovered by radio amateurs is now confirmed by research and recognized by experts: if there is an admixture of oxygen in the copper of the wire, the thinnest, literally in a molecule, oxide film is formed on the metal crystallites, from which the sound signal can be anything but an improvement. In silver, this effect is not found, which is why sophisticated audio gourmets do not skimp on silver wire: merchants shamelessly cheat with copper wires, because. it is possible to distinguish oxygen-free copper from ordinary electrical engineering only in a specially equipped laboratory.

Speakers

The quality of the primary sound emitter (FROM) on the bass determines the sound of the speakers approx. by 2/3; in the midrange and highs - almost completely. In amateur speakers, almost always IZs are electrodynamic GGs (speakers). Isodynamic systems are quite widely used in high-end headphones (for example, TDS-7 and TDS-15, which are readily used by pros to control sound recording), but the creation of powerful isodynamic IS faces technical difficulties that are still insurmountable. As for the other primary ISs (see the list at the beginning), they are still far from “brought to mind”. This is especially true for prices, reliability, durability and stability of characteristics during operation.

When joining electroacoustics, you need to know the following about how speakers are arranged and work in acoustic systems. The exciter of the speaker is a thin coil of wire oscillating in the annular gap of the magnetic system under the influence of an audio frequency current. The coil is rigidly connected to the sound emitter itself into space - a diffuser (for bass, midrange, sometimes for high frequencies) or a thin, very light and rigid dome diaphragm (for high frequencies, rarely for midrange). The efficiency of sound emission strongly depends on the diameter of the IZ; more precisely, it depends on its relation to the wavelength of the emitted frequency, but at the same time, with an increase in the diameter of the IZ, the probability of occurrence of non-linear distortions (NI) of the sound due to the elasticity of the IZ material also increases; more precisely - not its infinite rigidity. They fight against NI in IZ by making radiating surfaces from sound-absorbing (anti-acoustic) materials.

The diameter of the cone is larger than the diameter of the coil, and in diffuser GGs, it and the coil are attached to the speaker housing with separate flexible suspensions. The diffuser configuration is a thin-walled hollow cone with its apex facing the coil. The suspension of the coil simultaneously holds the top of the diffuser, i.e. its suspension is double. The generatrix of a cone can be rectilinear, parabolic, exponential and hyperbolic. The steeper the cone of the diffuser converges to the top, the higher the return and the lower the NI dynamics, but at the same time its frequency range narrows and the radiation directivity increases (the radiation pattern narrows). The narrowing of the DN also narrows the area of the stereo effect and moves it away from the frontal plane of the speaker pair. The diameter of the diaphragm is equal to the diameter of the coil and there is no separate suspension for it. This drastically reduces the SOI GG, because. the diffuser suspension is a very noticeable source of NI sound, and the material for the diaphragm can be taken very hard. However, the diaphragm is capable of emitting sound well only at sufficiently high frequencies.

The coil and the diffuser or diaphragm, together with the suspensions, make up the mobile system (PS) of the GG. The PS has a frequency of its own mechanical resonance Fp, at which the mobility of the PS increases sharply, and a quality factor Q. If Q> 1, then the speaker without a properly selected and executed acoustic design (see below) at Fp will wheeze at a power less than the nominal one, not that peak, this is the so-called. blocking GG. Locking does not apply to distortions, because is a design and manufacturing defect. If 0.7

The efficiency of transferring the energy of an electrical signal from the energy to sound waves in the air is determined by the instantaneous acceleration of the diffuser / diaphragm (who is familiar with mathematical analysis - the second derivative of its displacement with respect to time), since air is highly compressible and highly fluid. The instantaneous acceleration of the coil pushing/pulling the diffuser/diaphragm must be somewhat greater, otherwise it will not "shake" the OUT. A few, but not much. Otherwise, the coil will bend and cause the emitter to vibrate, which will lead to the appearance of NI. This is the so-called membrane effect, in which longitudinal elastic waves propagate in the diffuser/diaphragm material. Simply put, the diffuser / diaphragm should “slow down” the coil a little. And here again there is a contradiction - the stronger the emitter “slows down”, the stronger it radiates. In practice, the "braking" of the emitter is done in such a way that its NI in the entire range of frequencies and powers fit into the norm for a given Hi-Fi class.

Note, output: do not try to "squeeze" out of the speakers what they cannot. For example, speakers on 10GDSh-1 can be built with a frequency response unevenness at the midrange of 2 dB, but in terms of SOI and dynamics, it still pulls on Hi-Fi no higher than the initial one.

At frequencies up to Fp, the membrane effect never manifests itself, this is the so-called. piston mode of operation of the GG - the diffuser / diaphragm just go back and forth. Higher in frequency, the heavy diffuser is no longer able to keep up with the coil, the membrane radiation starts and gets stronger. At a certain frequency, the speaker begins to radiate only as a flexible membrane: at the junction with the suspension, its diffuser is already motionless. At 0.7

The membrane effect dramatically improves the return of GG, tk. the instantaneous accelerations of the vibrating sections of the IZ surface turn out to be very large. This circumstance is widely used by designers of HF and partially MF GG, the distortion spectrum of which immediately goes into ultrasound, as well as when designing GG not for Hi-Fi. SOI GG with a membrane effect and the evenness of the frequency response of speakers with them strongly depend on the mode of the membrane. In the zero mode, when the entire surface of the FM trembles as if in time with itself, Hi-Fi up to the middle inclusive can be achieved at low frequencies, see below.

Note: the frequency at which the HG switches from the “piston to the membrane”, as well as the change in the membrane mode (not growth, it is always integer) significantly depend on the diffuser diameter. The larger it is, the lower in frequency and stronger the speaker begins to “membrane”.

Woofers

High-quality piston woofers GG (simply - “piston”; in English woofers, barking) are made with a relatively small, thick, heavy and hard anti-acoustic cone on a very soft latex suspension, see pos. 1 in fig. Then Fr is below 40 Hz or even below 30-20 Hz, and Q<0,7. В мембранном режиме поршневые ГГ способны работать до частот 7-8 кГц на нулевой-первой модах.

The periods of low-frequency waves are long, all this time the diffuser in the piston mode must move with acceleration, and therefore the diffuser stroke becomes long. Low frequencies without acoustic design are not reproduced, but it is always closed to one degree or another, isolated from free space. Therefore, the diffuser has to work with a large mass of so-called. of the attached air, for the “buildup” of which a significant effort is required (which is why piston GGs are sometimes called compression), as well as for the accelerated movement of a heavy diffuser with a low quality factor. For these reasons, the magnetic system of the piston GG has to be made very powerful.

Despite all the tricks, the return of the piston GG is small, because. it is impossible for a low-frequency diffuser to develop a large acceleration at long waves: the elasticity of the air is not enough to accept the energy given off. It will spread to the sides, and the speaker will go into locking. In order to increase the return and smoothness of the movement of the moving system (to reduce SOI at high power levels), designers go all out - they use differential magnetic systems, with half-scattering, and other exotics. THD is further reduced by filling the magnetic gap with a non-drying rheological fluid. As a result, the best modern pistons reach a dynamic range of 92-95 dB, and the THD at nominal power does not exceed 0.25%, and at peak power - 1%. All this is very good, but the prices - mom, don't worry! $1000 for a pair with differential magnets and refilling for home acoustics, matched in terms of output, resonant frequency and flexibility of the moving system, is not the limit.

Note: LF GG with rheological filling of the magnetic gap are suitable only for LF links of 3-way speakers, because completely incapable of working in the membrane mode.

Piston GGs have another serious flaw: without strong acoustic damping, they can mechanically collapse. Again, simply: behind the piston speaker there should be a kind of air cushion loosely connected to the free space. Otherwise, the diffuser at the peak will break off the suspension and it will fly out along with the coil. Therefore, you can not put the "piston" in any acoustic design, see below. In addition, piston GGs do not tolerate forced braking of the PS: the coil burns out immediately. But this is already a rare case, the speaker cones are usually not held by hand and matches are not inserted into the magnetic gap.

Craftsmen take note

There is a known “folk” way to increase the return of piston GGs: from the rear, without altering anything in dynamics, an additional annular magnet is firmly attached to the standard magnetic system with the repelling side. It is repulsive, otherwise, when a signal is applied, the coil will immediately be torn off from the diffuser. In principle, it is possible to rewind the speaker, but it is very difficult. And nowhere else has a rewinding speaker become better or at least remain the same as it was.

But it's not really about that. Enthusiasts of this refinement claim that the field of an external magnet concentrates the field of a regular magnet near the coil, which increases the acceleration of the PS and recoil. This is true, but Hi-Fi GG is a very finely balanced system. Recoil is actually a little higher. But here the SOI at its peak immediately "jumps" so that sound distortions become well audible even to inexperienced listeners. At nominal, the sound can become even cleaner, but without Hi-Fi speakers it’s already high-fi.

Leading

So in English (managers) are called SC GG, because. it is the midrange that accounts for the vast majority of the semantic load of the musical opus. The requirements for the midrange GG for Hi-Fi are much softer, so most of them are made of a traditional design with a large cone, cast from cellulose mass along with the suspension, pos. 2. Reviews about the midrange of the dome and with metal diffusers are contradictory. The tone prevails, they say, the sound is harsh. Fans of the classics complain that the bowed speakers squeal from the "non-paper" speakers. Almost everyone recognizes the sound of the midrange GG with plastic diffusers as dull and at the same time hard.

The course of the diffuser of the midrange GG is made short, because. its diameter is comparable to the wavelengths of the MF and the transfer of energy into the air is not difficult. To increase the attenuation of elastic waves in the diffuser and, accordingly, reduce NI, along with expanding the dynamic range, finely chopped silk fibers are added to the mass for casting the Hi-Fi cone midrange GG, then the speaker operates in a piston mode in almost the entire midrange range. As a result of the application of these measures, the dynamics of modern midrange GG of the average price level turns out to be no worse than 70 dB, and THD at a nominal value of no more than 1.5%, which is quite enough for high Hi-Fi in a city apartment.

Note: silk is added to the cone material of almost all good speakers, it is a universal way to reduce THD.

Tweeters

In our opinion - squeakers. As you may have guessed, these are tweeters, HF YY. Spelled with a single t, it's not a gossip social media name. It would be generally easy to make a good “tweeter” from modern materials (the NI spectrum immediately goes into ultrasound), if not for one circumstance - the diameter of the emitter in almost the entire HF range turns out to be of the same order or less than the wavelength. Because of this, interference is possible on the emitter itself due to the propagation of elastic waves in it. In order not to give them a “hook” for radiation into the air at random, the diffuser / dome of the HF GG should be as smooth as possible, for this purpose the domes are made of metallized plastic (it absorbs elastic waves better), and the metal domes are polished.

The criterion for choosing the HF GG is indicated above: dome ones are universal, and for fans of the classics who require necessarily “singing” soft tops, diffuser ones are more suitable. It is better to take these elliptical ones and put them in the speakers, orienting their long axis vertically. Then the dynamics of the dynamics in the horizontal plane will be wider, and the stereo zone will be larger. Still on sale there is a HF GG with a built-in horn. Their power can be taken as 0.15-0.2 of the power of the low-frequency link. As for technical quality indicators, any HF GG is suitable for Hi-Fi of any level, as long as it is suitable in terms of power.

Widths

This is a colloquial nickname for broadband GGs (GGSh) that do not require defiltering of AC frequency channels. The emitter of a simple GGSh with a common excitation consists of an LF-MF diffuser and a HF cone rigidly connected to it, pos. 3. This is the so-called. a coaxial radiator, which is why the GGSh is also called coaxial speakers or simply coaxes.

The idea of GGSh is to give the membrane mode to the HF cone, where it does not particularly harm, and let the diffuser on the bass and at the bottom of the midrange work “on the piston”, for which the bass-midrange cone is corrugated across. This is how broadband GGs are made for initial, sometimes average Hi-Fi, for example. mentioned 10GD-36K (10GDSH-1).

The first HF cone GGS went on sale in the early 50s, but they never achieved a dominant position in the market. The reason is the tendency to transient distortion and the delay in the attack of the sound because the cone dangles and sloshes from the shocks of the cone. Listening to Miguel Ramos playing the Hammond electric organ through a coax with a cone is unbearably painful.

Coaxial GGSh with separate excitation of LF-MF and HF emitters, pos. 4, this shortcoming is devoid of. In them, the RF link is driven by a separate coil from its own magnetic system. The sleeve of the HF coil passes through the LF-MF coil. PS and magnetic systems are located coaxially, i.e. along one axis.

GGSh with separate excitation at low frequencies in all technical parameters and subjective sound assessments are not inferior to piston GGs. On modern coaxial speakers, you can build very compact speakers. The disadvantage is the price. A coaxial for high Hi-Fi is usually more expensive than a LF-MF + HF set, although it is cheaper than LF, MF and HF for a 3-way speaker.

Auto

Car speakers formally also belong to coaxial speakers, but in reality they are 2-3 separate speakers in one case. HF (sometimes midrange) GG are suspended in front of the diffuser LF GG on the bracket, see on the right in fig. at the beginning. Filtering is always built-in, i.e. There are only 2 terminals on the case for connecting wires.

The task of auto speakers is specific: first of all, to “shout out” the noise in the car, so their designers don’t really struggle with the membrane effect. But for the same reason, auto-speakers need a wide dynamic range, at least 70 dB, and their cones are necessarily made with silk or use other measures to suppress higher membrane modes - the speaker should not wheeze even in a car on the move.

As a result, auto speakers are in principle suitable for Hi-Fi up to medium inclusive, if you choose the right acoustic design for them. In all the speakers described below, you can put auto-speakers of a suitable size and power, then you will not need a cutout for the HF GG and filtering. One condition: the standard terminals with clamps must be very carefully removed and replaced with lamellas for wiring. Speakers made from modern car speakers allow you to listen to good jazz, rock, even individual pieces of symphonic music and many chamber music. Of course, they won't pull Mozart's violin quartets, but very few people listen to such dynamic and meaningful opuses. A pair of auto speakers will cost several times, up to 5 times, cheaper than 2 sets of GG with filter components for a 2-way speaker.

frisky

Friskers, from frisky, this is how American radio amateurs called small-sized low-power GGs with a very thin and light cone, firstly, for their high output - a pair of “frisky” 2-3 W each sounds a room of 20 square meters. m. Secondly - for the hard sound: "frisky" work only in the membrane mode.

Manufacturers and sellers do not single out “frisky” in a special class, because. they are, in theory, not Hi-Fi. The speaker is like a speaker in any Chinese radio or cheap computer speakers like that. However, on the "frisky" one can make good speakers for the computer, providing Hi-Fi up to and including the average in the vicinity of the desktop.

The fact is that the "frisky" ones are able to reproduce the entire sound range, you only need to reduce their SOI and smooth out the frequency response. The first is achieved by adding silk to the diffuser, here you need to navigate by the manufacturer and his (not trade!) Specifications. For example, all GGs of the Canadian company Edifier with silk. By the way, Edifier is a French word and is read "edifier" and not "idifier" in the English manner.

The frequency response of the "frisky" is leveled in two ways. Small bursts / dips are already removed by silk, and larger bumps and troughs are eliminated by acoustic design with free exit to the atmosphere and a damping pre-chamber, see fig.; see an example of such an AS below.

Acoustics

Why do you need acoustic design at all? At low frequencies, the dimensions of the sound emitter are very small compared to the length of the sound wave. If you just put the speaker on the table, the waves from the front and rear surfaces of the diffuser will immediately converge in antiphase, cancel each other out, and you won’t hear bass at all. This is called an acoustic short circuit. You can’t just muffle the speaker from the rear to the bass: the diffuser will have to strongly compress a small volume of air, which is why the resonance frequency of the PS will “jump” so high that the speaker simply cannot reproduce the bass. From here follows the main task of any acoustic design: either to extinguish the radiation from the rear side of the GG, or to turn it over by 180 degrees and re-emit it in phase from the front of the speaker, while at the same time preventing the expenditure of the energy of the diffuser movement on thermodynamics, i.e. on compression-expansion of air in the AC case. An additional task is, if possible, to form a spherical sound wave at the output of the speaker, because in this case, the stereo effect zone is the widest and deepest, and the effect of room acoustics on the sound of the speakers is the least.

Note, an important corollary: for each speaker cabinet of a specific volume with a specific acoustic design, there is an optimal excitation power range. If the output power is low, it will not swing the acoustics, the sound will be dull, distorted, especially at low frequencies. An excessively powerful GG will go into thermodynamics, which will cause blocking.

The purpose of the speaker cabinet with acoustic design is to provide the best reproduction of low frequencies. Durability, stability, appearance - by itself. Acoustically, home speakers are designed in the form of a shield (speakers built into furniture and building structures), an open box, an open box with an acoustic impedance panel (PAS), a closed box of normal or reduced volume (small-sized acoustic systems, MAC), a phase inverter (FI), passive radiator (PI), direct and reverse horns, quarter-wave (HF) and half-wave (HF) labyrinths.

Built-in acoustics is a subject of special discussion. Open boxes from the era of tube radios, it is unrealistic to get an acceptable stereo from them in an apartment. Of the others, it is best for a beginner for his first AS to opt for a PV labyrinth:

Unlike others, except FI and PI, PV labyrinth allows you to improve bass at frequencies below the natural resonant frequency of the woofer.
Compared to the FI PV, the labyrinth is structurally and easy to set up.
Compared to PI PV, the labyrinth does not require expensive purchased additional components.
The cranked PV labyrinth (see below) creates a sufficient acoustic load for the GG, while at the same time having a free connection with the atmosphere, which makes it possible to use low-frequency GG with both long and short diffuser strokes. Up to replacement in already built speakers. Of course, only a couple. The radiated wave in this case will be practically spherical.
Unlike all, except for the closed box and the HF labyrinth, the acoustic column with the PV labyrinth is able to smooth out the frequency response of the LF GG.
Speakers with a PV labyrinth are structurally easily pulled into a tall thin column, which facilitates their placement in small rooms.

As for the penultimate point - are you surprised if experienced? Consider this one of the promised revelations. And see below.

PV maze

Labyrinths are often considered acoustic design such as a deep slot (Deep Slot, a type of HF labyrinth), pos. 1 in Fig., and convolutional reverse horn (pos. 2). We will touch on the horns, but as for the deep slot, this is actually a PAS, an acoustic shutter that provides free communication with the atmosphere, but does not let sound out: the depth of the slot is a quarter of the wavelength of its tuning frequency. It is easy to verify this by measuring the sound levels in front of the front of the speaker and in the opening of the slot using a highly directional microphone. Resonance at multiple frequencies is suppressed by lining the gap with a sound absorber. A deep slot speaker also dampens any speakers, but raises their resonant frequency, albeit less than a closed box.

The initial element of the PV labyrinth is an open half-wave pipe, pos. 3. As an acoustic design, it is unsuitable: while the wave from the rear reaches the front, its phase will be reversed by another 180 degrees, and the same acoustic short circuit will turn out. On the frequency response of the PV, the pipe gives a high sharp peak, causing the GG to lock at the tuning frequency Fn. But what is already important - Fn and the natural resonance frequency of the GG f (which is higher - Fp) are theoretically not related to each other, i.e. bass can be expected to improve below f (Fp).

The easiest way to turn a pipe into a maze is to bend it in half, pos. 4. This will not only phase the front with the rear, but also smooth out the resonant peak, because the paths of the waves in the pipe will now be different in length. In this way, in principle, it is possible to smooth the frequency response to any predetermined degree of evenness by increasing the number of knees (it should be odd), but in reality it is very rare to use more than 3 knees - the damping of the wave in the pipe interferes.

In the chamber PV labyrinth (pos. 5), the knees are divided into the so-called. Helmholtz resonators - cavity tapering towards the rear end. This further improves the damping of the HG, smoothes the frequency response, reduces losses in the labyrinth and increases the radiation efficiency, because. the rear exit window (port) of the labyrinth always works with "backwater" from the last chamber. Having partitioned the chambers on intermediate resonators, pos. 6, it is possible to achieve a frequency response with a diffuser GG that almost satisfies the requirements of absolute Hi-Fi, but setting up each of a pair of such speakers requires somewhere from six months (!) of the work of an experienced specialist. Once upon a time, in a certain narrow circle, the labyrinth-chamber speaker with chamber separation was called Cremona, with a hint of the unique violins of Italian masters.

In fact, to obtain a frequency response for high Hi-Fi, it turns out that just a pair of cameras on the knee is enough. Drawings of speakers of this design are given in Fig; on the left - Russian development, on the right - Spanish. Both are very good outdoor acoustics. “For complete happiness”, it would not hurt the Russian woman to borrow the Spanish stiffness ties that support the partition (beech sticks with a diameter of 10 mm), and in return to give a smoothing of the pipe bend.

In both of these speakers, one more useful property of the chamber labyrinth is manifested: its acoustic length is greater than the geometric one, because the sound lingers somewhat in each chamber before passing on. Geometrically, these labyrinths are tuned to somewhere around 85 Hz, but measurements show 63 Hz. In reality, the lower limit of the frequency range is 37-45 Hz, depending on the type of LF GG. When the S-30B's filtered speakers are rearranged into such enclosures, the sound changes amazingly. For the better.

The excitation power range for these speakers is 20-80 W peak. Sound-absorbing lining here and there - synthetic winterizer 5-10 mm. Tuning is not always necessary and easy: if the bass is deaf, the port is covered symmetrically on both sides with pieces of foam until the optimal sound is obtained. This should be done slowly, each time listening to the same segment of the phonogram for 10-15 minutes. It must have strong mids with a sharp attack (mids control!), For example, a violin.

jet flow

The chamber labyrinth is successfully combined with the usual tortuous one. An example is the desktop acoustic system Jet Flow (jet stream) developed by American radio amateurs, which made a splash in the 70s, see fig. on right. Case width on the inside - 150-250 mm for speakers 120-220 mm, incl. "frisky" and autodynamics. Body material - pine, spruce, MDF. Sound-absorbing lining and adjustment are not required. Excitation power range - 5-30 W peak.

Note: there is confusion with Jet Flow now - jet sound emitters are sold under the same brand.

For high-spirited and computer

It is also possible to smooth out the frequency response of auto-speakers and “frisky” ones in an ordinary convoluted labyrinth by arranging a compression damping (not resonant!) prechamber in front of its entrance, indicated by K in Fig. below.

This mini speaker is designed for PC instead of the old cheap one. The speakers used are the same, but how they start to sound is simply amazing. If the diffuser is with silk, otherwise it makes no sense to fence the garden. An additional advantage is a cylindrical body, on which the midrange interference is close to the minimum, it is less only on a spherical body. Working position - with an inclination forward-up (AC - sound projector). Excitation power - 0.6-3 W nominal. Assembly is carried out in the following. order (glue - PVA):

For children 9 glue a dust filter (you can use scraps of nylon tights);
Det. 8 and 9 are pasted over with synthetic winterizer (indicated in yellow in the figure);
Assemble a package of partitions on the screed and spacers;
Glue the padding rings marked in green;
The package is wrapped, gluing, with whatman paper to a wall thickness of 8 mm;
The body is cut to size and the prechamber is pasted over (highlighted in red);
Paste children. 3;
After complete drying, they sand, paint, attach a stand, mount the speaker. Wires to it pass along the bends of the labyrinth.

About horns

Horn speakers have a high return (remember why he just does it, a mouthpiece). The old 10GDSH-1 yells through a horn so that the ears wither, and the neighbors “I can’t be happy at all”, which is why many are addicted to horns. In home speakers, convoluted horns are used as less bulky. The reverse horn is excited by the rear radiation of the GG and is similar to the PV labyrinth in that it rotates the phase of the wave by 180 degrees. But otherwise:

Structurally and technologically much more complicated, see fig. below.
It does not improve, but on the contrary, spoils the frequency response of the speakers, because The frequency response of any horn is uneven and the horn is not a resonating system, i.e. it is impossible to correct its frequency response in principle.
The radiation from the horn port is significantly directed, and its wave is rather flat than spherical, so a good stereo effect cannot be expected.
It does not create a significant acoustic load of the GG and at the same time requires significant power for excitation (we also remember whether they whisper into a speakerphone). The dynamic range of horn speakers can be extended at best to basic Hi-Fi, and for piston speakers with a very soft suspension (and therefore good and expensive ones), the cone breaks out very often when the GG is installed in the horn.
Gives overtones more than any other type of acoustic design.

Frame

The speaker cabinet is best assembled on beech dowels and PVA glue, its film retains its damping properties for many years. For assembly, one of the sidewalls is placed on the floor, the bottom, lid, front and rear walls, partitions are placed, see fig. on the right, and cover with the other sidewall. If the outer surfaces are to be finished, steel fasteners can be used, but always with gluing and sealing (plasticine, silicone) of non-glue seams.

Much more important for sound quality is the choice of body material. The ideal option is a musical spruce without knots (they are a source of overtones), but it is unrealistic to find its large boards for speakers, because Christmas trees are very knotty trees. As for the plastic cases of the speakers, they sound good only in industrial production, solid-cast, and amateur home-made products made of transparent polycarbonate, etc., are a means of self-expression, not acoustics. They will tell you that this sounds good - ask to turn it on, listen and believe your ears.

In general, it is difficult with natural wood materials for speakers: completely straight-grained pine without defects is expensive, and other available building and furniture species give overtones. It is best to use MDF. The Edifier mentioned above has long since completely switched to it. The suitability of any other tree for AS can be determined as follows. way:

The test is carried out in a quiet room, in which you yourself must first stay in silence for half an hour;
Piece of board approx. 0.5 m is placed on prisms from segments of a steel corner, laid at a distance of 40-45 cm from each other;
The knuckle of a bent finger knocks approx. 10 cm from any of the prisms;
Repeat tapping exactly in the center of the board.

If in both cases the slightest ringing is not heard, the material is suitable. The better, the softer, duller and shorter the sound. According to the results of such a test, you can make good speakers even from chipboard or laminate, see the video below.

What is the difference between 2-way and 3-way speakers? What do these stripes even mean, and what do they affect? The article will answer these questions. She says:

what are broadband speakers;
about the types of speakers;
about the crossover and its meaning.

All this will help you choose the best one, based on the requirements for sound quality and the actual purpose of the speakers.

Broadband speaker - what is it?

The principle of operation of broadband acoustics is based on the division of sound into different frequency ranges, which, thanks to special filters, overlap each other. Each such emitter works best only within certain frequency limits. It is in this limit that the sound is fed to the radiating head. This improves the sound.

To filter everything as it should be, acoustics developers combine:

inductors;
various resistors;
capacitors;

Interesting:a two-way outdoor speaker has an amazing 110 watts of power and deep bass. In addition, the stereo system has its own display and karaoke function.

This means that in such speakers, each speaker reproduces specific frequencies:

low;
medium;
high.

The number of bands in the speaker system directly affects the sound quality.

Previously, in the audio market, one-way acoustics was considered the standard solution, although it did not sound good. But at that time it was simply not possible to create a speaker that would be able to fully cover the entire frequency range. Modern manufacturers of single-band models have managed to significantly improve the sound, but this has not solved the problem of frequency separation by 100%. That's why audiophiles prefer full-range speakers.

However, if you choose a portable speaker, then the single-band option is perfect. For example, a three-watt bluetooth model not only sounds good, but also has a pleasant backlight - what you need for fun in nature.

Appearance in crossover speakers

Crossover is a special device that is used in acoustic systems. It prepares the desired frequency limit for each sound column (speaker).

Advice: it’s good if, in addition to the crossover, the speakers have magnetic shielding, like . It eliminates interference, even if you put acoustics next to a monitor or TV.

If the frequency of the signal that is fed into the subwoofer is out of range, it may distort the audio signal. If the boundaries are violated by high frequencies, then, in addition to distorted sound, the user may have problems with the “tweeter” - tweeter. Such a high-frequency pressure can simply disable the speaker.

That's what the crossover in the speakers is for: it will not upset the balance. This element prevents the frequency signal from going out of range.

Two-, three- and more-way speaker systems

In two-way systems, the scheme of operation is as follows: the midwoofer sounds almost everything: both bass and midrange, and the tweeter is responsible only for high frequencies. This can cause distortion of the signal in the form of a rise in tone, especially if the volume level is high enough. However, if you do not wind up the volume to the limit, then the distortion will not be noticeable.

Advice:it is better to choose speakers with a wooden case. They make the sound more voluminous and do not rattle at high frequencies, unlike models in plastic cases. For example, the case is made of MDF, so even at the maximum volume they listen well.

Three-way speakers differ from two-way speakers in that each driver has its own frequency. The presence of an additional speaker expands the direction of sound waves, due to which the composition sounds more realistic.

The main difference between three-way systems and others is that each speaker plays in piston mode. When the speaker is active, it starts to move. At the same time, both the central "points" of its diffuser, and those located along the perimeter, begin to equidistant from their location. Due to this distortion of the audio signal, either completely absent, or so insignificant that it is almost impossible to catch them.

Important: in the case of passive speakers, like, a lot depends on the amplifier, its frequency controls and power (it must match the speakers).

Models with a large number of bands do not distort the audio signal at all. But if you want this option, then you should look at large floor systems with large radiators: compact models with a large number of bands will sound louder, but less qualitatively.