Reproducible frequency range 20 20. Frequency response

frequency range

The frequency range is a frequency band reproduced by the system within certain limits in terms of amplitude (volume level) of the signal.

Amplifier frequency range

The frequency range is calculated based on the amplitude-frequency response graph data.

The amplitude-frequency response of an amplifier, as a rule, is a curve close to a straight line, with rolloffs (decrease in signal level) at the edges. The technical documentation indicates a frequency range that falls within a certain amplitude range. The example shows frequency ranges for deviations of 0, 3, 6 and 12 dB. Generally, the greater the deviation, the wider the frequency range that falls within the frequency range. If the deviation is not specified, then the specified frequency range does not provide useful or specific information.

An amplifier usually does not have a sharp drop in amplitude in the frequency response, so if it is indicated that the frequency range is 30 Hz - 18000 Hz at a level of -1 dB, then, for example, the amplifier also reproduces frequencies of 20 Hz and 25000 Hz, just with a level less than -1 dB. It could be -3 dB, or it could be -5 dB. Formally, no one obliges manufacturers to indicate the frequency range and it is indicated simply so that it is available. If it is not indicated within what deviation limits the frequency range is indicated, then the manufacturer only claims that the amplifier reproduces these frequencies, and that this level does not correspond to complete silence.

Headphone frequency range

The amplitude-frequency response of headphones, as a rule, is a curve, where the unevenness of the curve can reach both small and relatively high values. The frequency range can be 25 Hz - 28000 Hz ± 6 dB, which means that the graph line does not go beyond 6 dB relative to the average position of the line, where the distance between the deviation lines (value corridor) is 12 dB. In the example these are dotted orange lines. The designation 25 Hz - 28000 Hz - 12 dB will mean the same thing. In this designation, the top line of the corridor is taken as the base midline. The corridor designated as "-" may not take into account peaks and troughs at mid frequencies.

However, it happens that the graph line has higher deviations in peaks and valleys, and the frequency response may already look like 30 Hz - 20000 Hz ± 17 dB, which does not give an idea of ​​​​the nature of the sound. High deviations may be dictated by emphasizing certain frequency ranges for a special sound character or professional purposes. Also, the graph line can smoothly decrease (in the example, in the low-frequency region), which makes it difficult to indicate the edge of the frequency range, since the lower one sounds only a little quieter than the higher one, and does not become silent. And in this case, the frequency range can be indicated either for one of the standard values ​​± 3, ± 6 dB, or arbitrarily. Generally, the corridor designation practice of "±3/±6dB" is used for loudspeaker systems.

A particular difficulty lies in the fact that headphone measurement stands have different configurations and do not have a strict standard, unlike speaker systems. The frequency response at different stands has discrepancies, and the nature of the amplitude-frequency response does not favor designations within the corridor or deviation of the amplitude-frequency response from any base frequency. As a result, manufacturers set the frequency range based on their own considerations, and only rare models are indicated with a corridor or deviation. Without indicating a corridor or deviation, the numbers are more of a marketing nature than show the real state of affairs. There is no point in relying on such figures for comparative purposes between headphone models. It is also worth considering that manufacturers are not at all obliged to indicate the frequency range, sensitivity, impedance and other technical information and the list of specified characteristics is dictated to a large extent by the market itself. If the company believes that indicating the data will increase sales, then it indicates, if it thinks the opposite, then it does not indicates.

To compare the sound of headphones, in terms of which frequencies they reproduce and which they do not, it is based on amplitude-frequency response graphs measured under the same conditions.

Typically, the frequency range on the packaging is indicated without indicating deviations and measurement conditions. Such data does not allow for direct comparison, because For some headphones, a 6 dB corridor might initially be used, and for others, a 20 dB corridor, and headphones with a smaller frequency range in practice can play more confidently, against a model with a specified wide frequency range.

A characteristic type of frequency range designation, which is not recommended for comparison with the frequency ranges of other headphones.

In this form, the frequency range of the vast majority of headphones is indicated - regardless of their cost or area of ​​application.

Data that can be roughly compared has a range of values ​​indicated. In this case, two frequency ranges with different corridors of 3 and 10 dB are indicated for the Sennheiser HD800. Additionally, a typical amplitude-frequency characteristic is included, which can be used to create different frequency ranges in different corridors.

In this example, corridors can only be built in the range of 90 Hz - 14000 Hz, where the graph line is present. The above corridors and schedule complement each other.

The manufacturer can provide information on the frequency range without a corridor, but in conjunction with the amplitude-frequency characteristic.

The example shows the Ortofon e-Q7, which shows the frequency range without a corridor and a detailed graph of the amplitude-frequency response in the frequency range from 20 to 16,000 Hz.

Headphones can also come with a detailed amplitude-frequency response, as is done, for example, in the case of the Audez"e LCD-2.

One of the most respected families in audio is proud to introduce a new member. We are pleased to welcome the C314 professional condenser microphone, which is ideal for both stage and studio. Born from a commitment to absolute precision by the finest team of engineers, the C314 is made from the finest materials and components. It has gone through a demanding design and highly meticulous manufacturing process before achieving the final results: the microphone captures every detail of your creativity with precision. It doesn’t matter where you make your recordings in a large concert hall or in a small studio room, you need to capture emotions and moments that are important to you, but specifically the sound. With a full frequency response of 20 Hz – 20 kHz and very low self-noise, the C314 captures every nuance.

Built on the rich heritage of the C414 XLS capsule, its dual diaphragm guarantees the highest precision radiation pattern, and the built-in suspension system significantly reduces noise.
The versatile C314 is your gig's multi-instrumentalist, ready to perform wherever you need it. Whether it's cardioid, supercardioid, omnidirectional or figure-8, there are plenty of ways to get a more natural sound from any instrument, electric or acoustic guitar, drums, etc. Use a supercardioid to cut down on drum rumble, then quickly switch to a figure-8 for a balanced sound between two vocalists—all with easy access.

The C314 is an excellent partner for any studio, especially those with limited space. As a result, by giving up, you can make much more recordings of better quality, and if an overloaded signal appears, the LED indicator will immediately inform you. This will help you take full advantage of the huge dynamic range and switch the pad only when necessary. This bass filter suppresses vibration, hum, loud sounds and minimizes proximity effects for balanced recordings. This microphone's elegant exterior features a transparent, double-mesh metal grille that protects the internals and ensures robust immunity to radio interference, as well as a durable, scratch-resistant body that's always ready for transport.

Characteristics:

• Condenser microphone with 1” dual diaphragm
• Polar Pattern: Cardioid, Supercardioid, Omnidirectional, Figure-8
• Sensitivity: 20 mV/Pa
• Frequency range: 20 - 20000 Hz
• Resistance: 200 ohm
• Maximum SPL: 135/155 dB
• Equivalent noise level: 8 dB-A
• Signal to noise ratio: 86 dB
• Filter: 100 Hz, 12 dB/octave
• Pad: -20 dB
• Power supply: 44 – 52 V
• Connector: 3-pin XLR
• Dimensions: 160 x 55 x 43 mm
• Weight: 300 g

Many of us are accustomed to choosing equipment based on its technical characteristics. Is this approach applicable to choosing headphones? Let's figure it out... First of all, let's see what the list of technical characteristics of headphones is all about. Let’s immediately make a reservation that we will not consider such parameters as dimensions, weight, form factor, principle of operation and acoustic design - simply because, with the exception of the principle of operation, the meaning of all these parameters is obvious. And the story about the various principles of action would be quite long, and could result in a separate article.

Text: Ivan MUSINOV

We will consider only those characteristics that are directly related to headphone emitters. There are only four such characteristics:

• Frequency range
• Resistance
• Sensitivity
• Maximum input power

Let's look at each of these parameters in more detail.

Frequency range: does size matter?

In ordinary circles, this parameter is often given very great importance - sometimes even from sales consultants you hear that it is the main indicator of the sound quality of headphones. And you can notice the following practice among headphone manufacturers: for their more expensive and high-end models, they, as a rule, indicate a wider frequency range than for simpler and budget ones.

In fact, the range of reproduced frequencies not only has no relation to sound quality, but in general does not carry any semantic meaning. Why? - We'll figure it out now.

It has not yet been established exactly what range of sound frequencies a person can hear, however, the approximate boundaries of this range have been determined - from 20 Hz to 20 KHz. In fact, it makes no difference to a person whether the headphones are capable of reproducing anything outside this range, but it is important that everything that falls within this range is reproduced with a variation in volume that does not exceed reasonable limits (with a uniform volume level throughout the entire range, no headphones do not play).

Here it should be said that some manufacturers intentionally increase this spread by “raising” or, conversely, “dampening” certain parts of the frequency range, trying to give the sound of their headphones a certain, “proprietary” character - for example, recently the practice of “raising » a certain section of the high-frequency range in expensive headphones - so that their sound seems more detailed and intelligible. In any case, the range of reproduced frequencies does not give us any information about this variation in volume, rises and falls in different parts of the “frequency”.

In addition, it is worth noting that very few modern headphones are capable of reproducing high frequencies without “blockages” - for most models, in the region above 14 KHz, an intense decline in the volume level begins. So don’t be alarmed if your headphones have a stated range that does not reach the upper limit of 20 KHz (this often happens with headphones built on the basis of armature drivers).

By the way, no matter how wide the frequency range of the headphones specified by the manufacturer is, the headphones are capable of reproducing sounds of any frequency that are beyond its limits - only with a very large “blockage” in volume. And what kind of “blockage” should be considered large enough to designate it as the limit of the declared frequency range? 20 decibels, or maybe 30, or even more? In fact, there is no single standard in this regard, and each manufacturer is free to designate the boundaries of the range literally wherever he wishes. In such conditions, there can be no talk not only about the usefulness of such a characteristic as the range of reproduced frequencies of headphones, but also about its correctness or truthfulness.

Impedance matters for music from tablets and smartphones

This indicator means nothing more than the amount of electrical resistance of the headphones. It is usually recommended to pay attention to resistance for those who are going to use headphones with “low-power” sound sources - portable players, laptops, tablets, smartphones, as well as computer sound cards.

It is believed that with a sufficient level of sensitivity of the headphones (we will discuss what sensitivity is considered “sufficient” later), the optimal value of their resistance for portable players, smartphones, and tablets is no more than 50-70 Ohms, and for laptops and computer sound cards - no more than 100 Ohms (numbers, of course, are approximate and averaged). At the same time, it is not recommended to use headphones whose impedance is lower than the output impedance of the source (this applies to any, not just the “low-power” devices described above) - at a minimum, this is fraught with losses in sound quality, and at maximum, damage to the source. The latter, however, is only possible in extremely advanced cases.

It would seem that everything is simple - we look at the resistance and decide whether the headphones are suitable for our source or not. In reality, things are somewhat more complicated.

Headphone drivers actually have two similar characteristics: resistance to direct current and impedance (complex resistance), which reflects the resistance of the headphones to alternating current. Since the sound signal coming from the player to the headphones is just alternating current, of these two characteristics we are interested in impedance.

Isodynamic headphones have linear impedance - their resistance does not depend on the frequency of the alternating current. But for dynamic and reinforced headphones, the impedance depending on the frequency of the current supplied to them (and, accordingly, on the purity of the sound they reproduce) can be different.

Moreover, while some headphones have an insignificant impedance spread in frequency, for others it reaches serious values ​​- and this can have certain consequences for the sound quality. If in any part of the frequency range the impedance of the headphones is too low (lower than the output impedance of the source), a loss of resolution and an increase in the level of distortion will occur in this area. The situation is similar when a “low-power” source cannot cope with the too high impedance of the headphones.

A small example - many owners of the popular Koss Porta Pro portable headphones, who use them with players, note among their shortcomings a slow, “indistinct”, although powerful bass. Yes, these headphones are not record holders in terms of speed and bass intelligibility, but probably if their owners tried to connect them to a sufficiently powerful amplifier, they would notice a significant improvement in this parameter. But the thing is that although the stated resistance of the Koss Porta Pro is only 60 Ohms, which is quite normal for portable headphones, in the mid-bass area it increases to 140 Ohms - and most portable players give in.

Now the question is - why do most headphones have impedance indicated by only one number, and what is the use of this number? Answer: this figure, in most cases, reflects the impedance value at around 1000 Hz - it is believed that it is by this purity that the user determines and sets the volume that is comfortable for himself. The meaning of this figure is as follows: for most headphones, the “spread” of impedance depending on frequency is still not very large, and therefore this figure can serve as some kind of guideline when choosing headphones.

Headphone manufacturers rarely advertise full impedance graphs, but if you want to know everything about the impedance of a particular headphone model, you can most likely find the necessary information on the Internet.

Sensitivity reflects sound pressure level

In other words, the volume that headphones are capable of developing when a signal of a certain level is supplied to them. Talking about the uselessness of the “reproducible frequency range” characteristic, we have already mentioned that the volume of the headphones varies throughout the frequency range they reproduce - the headphones reproduce some parts of it louder, some quieter.

Based on what part of the frequency range is sensitivity measured? As a rule, this is the 1000 Hz mark - just as in the case of impedance.

The sensitivity of headphones is indicated either in decibels per milliwatt (dB/mW) or in decibels per volt (dB/V). Sensitivity expressed in dB/V is convenient because it can be used to compare with each other, without paying attention to resistance different models of headphones, and in particular, determine how suitable a particular model is for use with portable devices. The optimal sensitivity level for such headphones is at least 90 dB/V.

Knowing the resistance value of the headphones, you can convert the sensitivity expressed in dB/mW into sensitivity expressed in dB/V. There is the following formula for this:

Sensitivity (dB/V) = Sensitivity (dB/mW)+20Lg(1/),

Where R is the resistance of the headphones.

Maximum power - this parameter is in theory...

This parameter, in theory, should reflect the maximum power of the electrical signal that can be supplied to the headphones without the risk of damaging the emitters. As a rule, it is very underestimated and does not carry any practical meaning.

What headphone parameters indicate how the headphones sound? Alas, none - therefore, after comparing the technical characteristics of various models, it will not be possible to choose the most suitable sounding option.

We have already said more than once that the surest way to choose headphones is to come to the store and, after listening to several “candidates,” make a choice. If you do not have such an opportunity, we can recommend that you collect as much information as possible - reviews, measurements, reviews - about those models among which you are looking for “your one and only”, and make a decision based on them.

A home speaker system is one of the requirements for convenience. Great sound is the foundation of any entertainment system, whether you're listening to music, playing computer games or watching videos. Without excellent sound reproduction, even the most gorgeous film and wonderful game plot instantly fades and seems unfinished. In principle, this is understandable; information is perceived by all senses at the same time, so the low quality of one of the elements immediately affects the overall perception.

There are many sound output options; today we will focus on speaker systems. When choosing a speaker system for your computer, the user must decide which format is best for him.

First, let's look at a few terms so we don't have to dwell on them later.

Satellites (from Latin satellitis - satellite)- speakers in x.1 formats for reproducing mid- and high-frequency sounds.

Subwoofer- a speaker for reproducing the low-frequency range of sound frequencies (from 20 to 350 Hz). A subwoofer (or bass speaker) is the most powerful speaker in an acoustic system and often surpasses all satellites combined in power.

Now let’s look at the main formats of speaker systems:

2.0 - simple stereo. The system consists of two speakers, which are most often installed on the table at the edges of the monitor. It is necessary to take into account the distance between the speakers and not place them closely together. The speakers are designed to reproduce medium and high frequencies (two-way), some models can also reproduce low frequencies (three-way).

2.1 - a subwoofer is added to the stereo speakers - a special device for reproducing low frequencies. The placement of a 2.1 speaker system is comparable to a 2.0 configuration, except that the subwoofer is usually located lower (on a special shelf or floor) and away from the satellites. The subwoofer reproduces only low frequencies, and the satellites reproduce high and medium frequencies. The 2.1 system provides excellent bass, which will not be superfluous in games, movies or music.

4.0 - quadraphonic speaker system. This speaker provides surround sound. The satellites are located at the four corners of the square, and the listener should be in the middle between them.

4.1 - quadraphonic speaker with the addition of a subwoofer.

4.1 volumetric- one of many surround sound formats. Two satellites are located in front of the listener at the edges, between them there is a central channel, another satellite is installed behind the listener. A subwoofer is added to the four speakers, which is installed in front of the listener, but away from the front satellites (most often, on the floor).

5.1 - the main acoustic format of surround sound. The structure is similar to the 4.1 format, only two satellites are located behind the listener and they are placed at the edges, and not in the center. The feeling created by such an acoustic system (for example, when watching a movie) is simply indescribable! Naturally, with the correct settings. Indispensable when creating a home theater.

7.1 - the same surround sound acoustics as 5.1, but with more channels. More satellites are added on the sides of the listener. Naturally, this makes the surround sound even better. Mainly used for home cinema.

For computer games, 2.1 or 4.1 formats are suitable, stereo or quad speakers are responsible for the main environment, a subwoofer is for low frequencies (explosions, voice acting of monsters and other low-frequency special effects).

For movie lovers, it is better to choose speakers in 5.1 or 7.1 format. The satellites will create a surround environment (the so-called Dolby Surround, “surround sound”), and a separate speaker will be responsible for outputting the voice channel in the film (when viewed with a stereo system, this signal is usually muffled and the actors’ voices are hard to hear).

For music lovers, 2.0 speaker systems are recommended, since almost all music is now recorded in stereo format. Of course, there are separate speakers in 2.1 and 5.1 formats that will not spoil the sound quality, but there are quite a few of them (sound problems are primarily associated with the subwoofer, which introduces unnecessary noise and overtones into the sound). As an option, you can think about a quadraphonic system; the sound will actually be not so much surround, but a little unusual stereo.

When we have decided on the format of the speaker system and are ready to choose individual models, it is worth taking a closer look at the technical characteristics of the speakers.

Housing material

The material of the speaker system body has the greatest impact on sound quality. Modern speaker systems are made of plastic, chipboard, MDF or metal (some premium systems are made of special glass).

• Plastic is used for the manufacture of acoustic systems in the lower price category. The main advantage of using plastic is the ability to vary shape and design at low cost. In this case, frequent flaws occur in the sound, poor reproduction of the low-frequency range, and rattling at high volumes.
• Wood is an ideal material for making speakers, but it is very expensive (solid wood is used only in the production of elite speaker systems). The high cost is due to the labor-intensive processing processes; raw materials must be selected at the cutting down stage, kept for a long time and dried naturally.
• Plywood for use in AC usually has 12 or more layers, has good absorbent properties, and is lighter than chipboard and MDF. But, in comparison with the same chipboard and MDF, plywood is a very expensive material, which makes it practically inaccessible for mass production of acoustic systems.
• Chipboard (chipboard) is much cheaper than solid wood and plywood. Chipboards with a thickness of more than 16 mm have a high density, which helps reduce cabinet resonances. Due to its dense structure, chipboard does not introduce its own overtones into the sound of the acoustic system. Considering the low cost and good acoustic characteristics, chipboard is used by many manufacturers for speakers in the mid-price segment.
• MDF (Medium Density Fiberboard) is a common material in the manufacture of computer acoustics. The main advantages of MDF in the production of speakers are good absorption of sound vibrations and ensuring sufficient rigidity of the speaker body.
• For metal cases, aluminum and its alloys are usually used. They provide good mechanical qualities of the body: lightness, rigidity and density. Aluminum reduces resonance and improves high-frequency transmission. At the same time, metal, like plastic, allows you to realize the most daring design solutions. The main disadvantage of a metal case is its too “hard”, “metallic” sound.

None of the types of materials used in the manufacture of cabinets by themselves provide high-quality sound from the speakers. The technical characteristics of the amplifier, filters, speakers, as well as the quality of assembly and tuning of the speaker system also play a huge role here.

Power (RMS)

Many manufacturers often indicate “musical” power (P.M.P.O., Peak Music Power Output) in the technical characteristics of their models, which is determined according to the German standard DIN 45500.

According to this standard, a short-term signal with a frequency below 250 Hz is supplied to the speaker system. If there are no audible distortions, then the speaker is considered to have passed the test. In this case, nonlinear signal distortions are not taken into account. This method allows you to specify high "power" values, often 10-100 times the maximum sine wave. This parameter very poorly characterizes the actual quality of sound reproduction.

For a more realistic characteristic of the speaker, the power indicator RMS (Root Mean Squared - root mean square value) is used. This power is measured by applying a sinusoidal signal with a frequency of 1000 Hz until a certain level of non-linear distortion is reached. If the characteristics of a model say 25 W (RMS), it means that the speaker system, when a 25 W signal is supplied to it, can operate for a long time without mechanical damage to the speakers.

What power is needed for high-quality sound? This is determined by the parameters of the room in which the equipment is planned to be installed, the characteristics of the speaker itself, as well as the needs of the listener himself. For a room in a city apartment, for example, a system of up to 50 W is more than enough.

Frequency range (AFC - Amplitude-frequency response)

Frequency range is the range of frequencies reproduced by speakers. In x.1 formats, the frequency range is divided into two parts - low frequencies are reproduced by the subwoofer, and mid and high frequencies are reproduced by satellites.

The ideal frequency range is considered to be “20 Hz - 20000 Hz” (with slight rounding, the range of sound vibrations perceived by the human ear). True, in practice, such a range is unattainable by most speaker systems.

In most cases, manufacturers indicate only the cutoff frequencies and unevenness of the frequency response. For example, the frequency range “40 Hz - 18 kHz” means that in this range the sound of the speaker system is smooth and reliable. Below 40 Hz and above 18 kHz, the unevenness of the frequency response increases sharply. Below 40 Hz, the speakers will reproduce sounds unclearly, there may be a hum or strong attenuation of the signal, and above 18 kHz, crackling or hissing may appear.

The range value is strongly influenced by the number of playback bands of speaker systems. Optimal are three-way speakers with active separation of the signal into high-frequency, mid-frequency and low-frequency ranges, with the subsequent supply of each range to separate speakers of the speaker system. This division allows for independent amplification in different spectral bands and thereby ensures optimal operating mode for each speaker.

For games and movies, two-way systems will do, but for playing music (especially if you are a music lover and a connoisseur of pure sound), you should get a three-way speaker system.

Signal to noise ratio

Signal-to-noise ratio is a value equal to the ratio of the useful signal power to the noise power. Usually expressed in decibels.

SNR shows how loud the speaker amplifier makes noise (from 60 to 135.5 dB) if the volume control is turned up to maximum in the absence of a signal. The higher the signal-to-noise value, the clearer the sound the speakers provide. For high-quality speakers this figure is around 75 dB, for premium models it is at least 90 dB.

Acoustic design

There are several acoustic design options.

Closed box- a completely closed housing with dynamic head diffusers displayed on the front panel. This option has low efficiency and poor reproduction of the low-frequency range; it requires a fairly powerful amplifier.

A bass reflex pipe of a certain length and cross-section is mounted in the housing. With the correct calculation of the dimensions of the pipe and the volume of the speaker body, the bass reflex significantly improves the sound of the speaker system. It creates vibrations of sound waves that are in phase with the vibrations caused by the front side of the diffuser. Thanks to this, a significant increase in the low-frequency range and “softness” of the sound are achieved. This design is typical for speakers of 2.0 format.

Band-Pass (closed resonator box)- design for subwoofers. The speaker is installed inside the housing, and only the bass reflex pipe is brought out. The speaker itself does not directly participate in the formation of the low-frequency spectrum; instead, it only excites low-frequency sound vibrations, which then increase many times in volume in the bass reflex tube. The band pass is not always suitable for playing music, since at certain frequencies the subwoofer begins to “buzz”. This is why 2.1, 4.1 and 5.1 systems are generally not designed for music playback.

Requires the use of a complex and large housing. The column consists of a small compression-type dynamic head installed in the throat of the horn, due to which the efficiency of the speaker is significantly increased. The main advantage is deep and rich bass. At the same time, the acoustics will be massive, heavy and expensive. If you try to reduce the size of the speaker, and therefore the horn, the efficiency of the system will drop sharply.

(transmission line) is designed to dampen and dissipate radiation from the back side of the bass speaker cone. It is placed inside the housing and has an output hole, like a traditional bass reflex. The labyrinth allows you to get deep and high-quality bass, and also simplifies the load characteristics of the speakers. An acoustic labyrinth requires a large and complex cabinet, although its use provides only a slight advantage over a well-designed conventional bass reflex.

Omnidirectional (omnidirectional) speakers emit sound 360 degrees, which allows you to get a wide and voluminous stereo image. Omnidirectional acoustics can fill a room with sound that will be perceived by listeners almost anywhere in the room. At the same time, the sound picture between two such speakers will not be as accurate and focused as in the case of using traditional acoustics.

U electrostatic speakers The diffuser that emits sound vibrations is a thin film with an electrostatic charge. This film is so light that it does not store kinetic energy and therefore does not resonate. This effect produces a transparent and clear sound, free from coloration and distortion. These speakers are great for vocal and classical music, where accuracy and smoothness of sound are important. The problem is that the open back panel of such speakers requires free placement in the listening room, at a considerable distance from the walls. The speaker requires a power source and a high-quality amplifier. The limited bass range necessitates the use of an additional woofer or a separate subwoofer.

Magneto-planar speakers the principle of operation is similar to electrostatic ones, however, in them the radiating film oscillates under the influence of a passing sound signal in a constant magnetic field. Magneto-planar speakers sound clean and transparent, and are excellent for reproducing vocals, including choral parts. Unlike electrostatic speakers, they do not require a power source. The disadvantages are basically the same. Size, bad bass, need a good amplifier.

IN ribbon speakers To create sound waves, thin aluminum foil vibrates in a constant magnetic field. The ribbon driver reproduces sound with low distortion, but is absolutely not suitable for working in the low frequency range. Apart from poor bass, another problem with ribbon speakers is the slight metallic sound.

Speaker sizes

Compact bookshelf acoustics (height ~25 cm)

Bookshelf speakers are inexpensive, compact, and can provide good sound, at least in stereo. Typically have a neutral tonal balance.

The main disadvantage is shallow bass. In addition, bookshelf speakers have low sensitivity and in order to get loud sound from them, at least 40 W of input power is required. If too much power is applied, on the contrary, audible sound distortion occurs (in the worst case, the voice coils heat up and burn out).

When positioned close to the wall, you must choose speakers with a bass reflex on the front panel. Among other things, this placement will enhance the bass to some extent.

Medium sized rack speakers (~35 cm high)

Rack-mounted acoustics are larger in volume than bookshelf speakers and are capable of providing very deep low frequencies (the sound range of string bass instruments). Acoustics of this class represent a good compromise between size and sound quality.

The main disadvantage is the large size for placing them on a workplace or bookshelf. If you use special racks, then such a system will occupy space like large floor-standing speakers.

Compact floor-standing acoustics (height ~ 100 cm)

Floor standing speakers can produce bass that is already convincing and deep enough to shake your living room floor. With a relatively modest height, compact floor-standing acoustics can have a low-frequency range below 30 Hz. Taking up the space of a smaller rack-mount speaker, floor-standing models produce better sound, have greater sensitivity and do not require a heavy-duty amplifier.

The main disadvantages are also associated with the dimensions of floor-standing speakers. By itself, such a system will look massive in a small room, and for better sound the speakers will have to be moved further away from the walls (which makes them stand out even more in space). In addition, floor-standing speakers must be firmly secured to the floor so that there is no additional vibration of the frame.

Large floor-standing acoustics (over 120 cm in height)

Large floor-standing speakers can operate at high power inputs and have deep bass. Several woofers can be built into the column to expand the low-frequency range. Large floor-standing acoustics are highly sensitive and, even with a small input power, are capable of high-quality sound in a room of considerable size, sound large and comfortable, have low distortion in the bass and a wide dynamic range.

The massiveness of such systems can attract attention, especially if the room is not so large. And they are, to put it mildly, not cheap.

Top list of speaker systems for January 2015

Stereo systems - 2.0

• Material - MDF
• Full music power - 24 W
• Frequency range - 70 Hz - 24000 Hz
• Overall dimensions - 226 x 197 x 140 mm
• Speaker system weight - 4.75 kg
• Color - black, brown

• Material - MDF
• Full music power - 30 W
• Frequency range - 63 Hz - 24000 Hz
• Signal-to-noise ratio, dB - ≥ 85
• Magnetic shielding - yes
• Overall dimensions - 220 x180 x140 mm
• Speaker system weight - 6.8 kg
• Color - black, brown

• Material - MDF
• Total music power - 42 W
• Frequency range - 75 Hz - 18000 Hz
• Signal-to-noise ratio, dB - ≥ 85
• Magnetic shielding - yes
• Overall dimensions - 234 x 196 x 146 mm
• Speaker system weight - 4.9 kg
• Color - black, brown

• Material - MDF
• Full music power - 50 W
• Frequency range - 45 Hz - 24000 Hz
• Magnetic shielding - yes
• Overall dimensions - 160 × 255 × 200 mm
• Speaker system weight - 5.2 kg
• Black color

• Material - MDF
• Full music power - 124 W
• Signal-to-noise ratio, dB - ≥ 85
• Magnetic shielding - yes
• Overall dimensions - 218 x 370 x 292 mm
• Speaker system weight - 16 kg
• Black color

• Material - MDF
• Full music power - 100 W
• Signal-to-noise ratio, dB - ≥ 85
• Magnetic shielding - yes
• Overall dimensions - 210 x 270 x 361 mm
• Speaker weight - 13.7 kg
• Color - black, brown

• Material - MDF
• Frequency range - 50 Hz - 20000 Hz
• Magnetic shielding - yes
• Overall dimensions - 214 x 575 x 323 mm
• Speaker weight - 21.9 kg
• Color - black, brown

• Material - MDF
• Full musical power - 140 W
• Frequency range - 40 Hz - 20000 Hz
• Signal-to-noise ratio, dB - ≥ 85
• Magnetic shielding - yes
• Overall dimensions - 258 x 463 x 320 mm
• Speaker weight - 27.8 kg
• Black color

Three-component acoustics - 2.1

• Material - plastic
• Total Music Power - 48W (2x9W + 32W)
• Frequency range - 50 Hz - 20000 Hz
• Signal-to-noise ratio, dB - ≥ 80
• Magnetic shielding - yes
• Overall dimensions of the subwoofer - 248 x 199 x 294 mm
• Overall dimensions of the satellites - 69 x 234 x 118 mm
• Speaker system weight - 4.1 kg
• Color - black, white

• Material - MDF
• Full music power - 80W (2x20W + 40W)
• Frequency range - 35 Hz - 25000 Hz
• Signal-to-noise ratio, dB - ≥ 85
• Magnetic shielding - yes
• Overall dimensions of the subwoofer - 265 × 265 × 265 mm
• Overall dimensions of the satellites - 120 × 202 × 125 mm
• Overall dimensions of the amplifier block - 69 × 200 × 220 mm
• Speaker system weight - 7.5 kg
• Brown color

• Material - MDF
• Total Music Power - 53W (2x9W + 35W)
• Frequency range - 55 Hz - 18000 Hz
• Signal-to-noise ratio, dB - ≥ 85
• Magnetic shielding - yes
• Overall dimensions of the satellites - 90 x 180 x 130 mm
• Speaker system weight - 7.8 kg
• Black color

• Material - MDF (subwoofer), plastic (satellites)
• Full music power - 200W (2x35W + 130W)
• Magnetic shielding - yes
• Overall dimensions of the subwoofer - 303 × 264 × 282 mm
• Overall dimensions of the satellites - 116 × 195 × 135 mm
• Speaker system weight - 8.3 kg
• Black color

• Material - MDF
• Total Music Power - 140W (2x35W + 70W)
• Frequency range - 20 Hz - 20000 Hz
• Signal-to-noise ratio, dB - ≥ 85
• Magnetic shielding - yes
• Overall dimensions of the subwoofer - 274 x 309 x 468 mm
• Overall dimensions of the satellites - 116 x 203 x 160 mm
• Speaker system weight - 19 kg
• Black color

Six-channel systems - 5.1

• Material - MDF
• Total Music Power - 65W (5x8W + 25W)
• Frequency range - 30 Hz - 20000 Hz
• Signal-to-noise ratio, dB - ≥ 75
• Overall dimensions of the subwoofer - 190 x 267 x 400 mm
• Overall dimensions of the satellites - 95 x 218 x 103 mm (center), 198 x 106 x 103 mm (sides)
• Weight of acoustic systems - 10 kg
• Black color

• Material - MDF
• Total Music Power - 80W (4x8W + 10W + 38W)
• Frequency range - 45 Hz - 18000 Hz
• Signal-to-noise ratio, dB - ≥ 85
• Overall dimensions of the subwoofer - 232 x 242 x 288 mm
• Overall dimensions of the satellites - 180 x 90 x 130 mm (center), 90 x 180 x 130 mm (sides)
• Overall dimensions of the amplifier block - 78 x 255 x 250 mm
• Speaker system weight - 12.6 kg
• Black color

• Material - MDF
• Total Music Power - 270W (5x32W + 110W)
• Frequency range - 20 Hz - 25000 Hz
• Signal-to-noise ratio, dB - 92
• Overall dimensions of the subwoofer - 267 x 340 x 310 mm
• Overall dimensions of the satellites - 122 x 220 x 182 (small), 240 x 1000 x 200 mm (tower), 220 x 122 x 182 mm (center)
• Speaker system weight - 33.5 kg
• Brown color

• Material - MDF
• Total Music Power - 500W (5x67W + 165W)
• Frequency range - 35 Hz - 20000 Hz
• Signal to noise ratio, dB - ≥ 95
• Overall dimensions of the subwoofer - 280 × 318 × 292 mm
• Overall dimensions of the satellites -99 × 92 × 163 mm
• Speaker system weight - 12.7 kg
• Black color

• Material - MDF
• Total Music Power - 540W (5x60W + 240W)
• Frequency range - 42 Hz - 20000 Hz
• Signal-to-noise ratio, dB - ≥ 85
• Overall dimensions of the subwoofer - 367 x 397 × 489 mm
• Overall dimensions of the satellites - 316 x 117 × 157 mm (center), 116 x 203 × 160 mm (sides)
• Weight of acoustic systems - 30 kg
• Black color

Comparative testing of Edifier and Microlab stereo speakers (April 2014)

Power

By the word power in colloquial speech, many mean “power”, “strength”. Therefore, it is quite natural that buyers associate power with volume: “The more power, the better and louder the speakers will sound.” However, this popular belief is completely wrong! It is not always the case that a speaker with a power of 100 W will play louder or better than one that has a power rating of “only” 50 W. The power value rather speaks not about volume, but about the mechanical reliability of the acoustics. The same 50 or 100 W is not a sound volume at all, published by the column. Dynamic heads themselves have low efficiency and convert only 2-3% of the power of the electrical signal supplied to them into sound vibrations (fortunately, the volume of the sound produced is quite enough to create sound). The value indicated by the manufacturer in the passport of the speaker or the system as a whole only indicates that when a signal of the specified power is supplied, the dynamic head or speaker system will not fail (due to critical heating and interturn short circuit of the wire, “biting” of the coil frame, rupture of the diffuser , damage to flexible suspensions of the system, etc.).

Thus, the power of an acoustic system is a technical parameter, the value of which is not directly related to the loudness of the acoustics, although it is somewhat related to it. The rated power values ​​of the dynamic heads, amplifier path, and speaker system may be different. They are indicated, rather, for orientation and optimal pairing between the components. For example, an amplifier of significantly lower or significantly higher power can damage the speaker in the maximum positions of the volume control on both amplifiers: on the first - due to the high level of distortion, on the second - due to the abnormal operation of the speaker.

Power can be measured in different ways and under different test conditions. There are generally accepted standards for these measurements. Let's take a closer look at some of them, most often used in the characteristics of products from Western companies:

RMS (Rated Maximum Sinusoidal power— set maximum sinusoidal power). Power is measured by applying a 1000 Hz sine wave until a certain level of harmonic distortion is reached. Usually in the product passport it is written like this: 15 W (RMS). This value indicates that the speaker system, when supplied with a 15 W signal, can operate for a long time without mechanical damage to the dynamic heads. For multimedia acoustics, higher power values ​​in W (RMS) compared to Hi-Fi speakers are obtained due to measurements at very high harmonic distortion, often up to 10%. With such distortion, it is almost impossible to listen to the sound due to strong wheezing and overtones in the dynamic head and speaker body.

PMPO(Peak Music Power Output peak music power). In this case, power is measured by applying a short-term sine wave of less than 1 second duration and a frequency below 250 Hz (usually 100 Hz). In this case, the level of nonlinear distortions is not taken into account. For example, the speaker power is 500 W (PMPO). This fact suggests that the speaker system, after playing a short-term low-frequency signal, did not have any mechanical damage to the dynamic heads. Watt power units (PMPO) are popularly called “Chinese watts” due to the fact that power values ​​using this measurement technique reach thousands of watts! Imagine - active speakers for a computer consume 10 VA electrical power from the AC mains and at the same time develop a peak musical power of 1500 W (PMPO).

Along with Western ones, there are also Soviet standards for various types of power. They are regulated by GOST 16122-87 and GOST 23262-88, which are still in force today. These standards define concepts such as rated, maximum noise, maximum sinusoidal, maximum long-term, maximum short-term power. Some of them are indicated in the passport for Soviet (and post-Soviet) equipment. Naturally, these standards are not used in world practice, so we will not dwell on them.

We draw conclusions: the most important in practice is the value of power indicated in W (RMS) at harmonic distortion (THD) values ​​of 1% or less. However, comparison of products even by this indicator is very approximate and may have nothing to do with reality, because sound volume is characterized by sound pressure level. That's why information content of the indicator “speaker system power” zero.

Sensitivity

Sensitivity is one of the parameters indicated by the manufacturer in the characteristics of speaker systems. The value characterizes the intensity of the sound pressure developed by the speaker at a distance of 1 meter when a signal is supplied with a frequency of 1000 Hz and a power of 1 W. Sensitivity is measured in decibels (dB) relative to the hearing threshold (zero sound pressure level is 2*10^-5 Pa). Sometimes the designation used is the characteristic sensitivity level (SPL, Sound Pressure Level). In this case, for brevity, in the column with units of measurement, dB/W*m or dB/W^1/2*m is indicated. It is important to understand that sensitivity is not a linear proportionality coefficient between sound pressure level, signal power and distance to the source. Many companies indicate the sensitivity characteristics of dynamic drivers measured under non-standard conditions.

Sensitivity is a characteristic that is more important when designing your own speaker systems. If you do not fully understand what this parameter means, then when choosing multimedia acoustics for a PC, you can not pay special attention to the sensitivity (fortunately, it is not often indicated).

frequency response

Amplitude-frequency response (frequency response) in the general case is a graph showing the difference in the amplitudes of the output and input signals over the entire range of reproduced frequencies. The frequency response is measured by applying a sinusoidal signal of constant amplitude when its frequency changes. At the point on the graph where the frequency is 1000 Hz, it is customary to plot the 0 dB level on the vertical axis. The ideal option is in which the frequency response is represented by a straight line, but in reality such characteristics do not exist in acoustic systems. When considering the graph, you need to pay special attention to the amount of unevenness. The greater the unevenness value, the greater the frequency distortion of the timbre in the sound.

Western manufacturers prefer to indicate the range of reproduced frequencies, which is a “squeeze” of information from the frequency response: only the limiting frequencies and unevenness are indicated. Let's say it says: 50 Hz - 16 kHz (±3 dB). This means that this acoustic system has reliable sound in the range of 50 Hz - 16 kHz, but below 50 Hz and above 15 kHz the unevenness increases sharply, the frequency response has a so-called “blockage” (a sharp decline in the characteristics).

What does this mean? A decrease in the level of low frequencies implies a loss of richness and richness of the bass sound. The rise in the low-frequency region causes a sensation of booming and humming of the speaker. In the blockages of high frequencies, the sound will be dull and unclear. High frequencies indicate the presence of irritating, unpleasant hissing and whistling sounds. In multimedia speakers, the magnitude of the frequency response unevenness is usually higher than in so-called Hi-Fi acoustics. All advertising statements by manufacturers about the frequency response of speakers of the type 20 - 20,000 Hz (theoretical limit of possibility) should be treated with a fair amount of skepticism. At the same time, the unevenness of the frequency response is often not indicated, which can amount to unimaginable values.

Since manufacturers of multimedia acoustics often “forget” to indicate the unevenness of the frequency response of the speaker system, when encountering a speaker characteristic of 20 Hz - 20,000 Hz, you need to keep your eyes open. There is a high probability of buying a thing that does not even provide a more or less uniform response in the frequency band 100 Hz - 10,000 Hz. It is impossible to compare the range of reproduced frequencies with different irregularities.

Nonlinear distortion, harmonic distortion

Kg harmonic distortion factor. An acoustic system is a complex electroacoustic device that has a nonlinear gain characteristic. Therefore, the signal will necessarily have nonlinear distortion at the output after passing through the entire audio path. One of the most obvious and easiest to measure is harmonic distortion.

The coefficient is a dimensionless quantity. It is indicated either as a percentage or in decibels. Conversion formula: [dB] = 20 log ([%]/100). The higher the harmonic distortion value, the worse the sound usually is.

The kg of speakers largely depends on the power of the signal supplied to them. Therefore, it is stupid to make absentee conclusions or compare speakers only by harmonic distortion coefficient, without resorting to listening to the equipment. In addition, for the working positions of the volume control (usually 30..50%), the value is not indicated by the manufacturers.

Total electrical resistance, impedance

The electrodynamic head has a certain resistance to direct current, depending on the thickness, length and material of the wire in the coil (this resistance is also called resistive or reactive). When a music signal, which is alternating current, is applied, the resistance of the head will change depending on the frequency of the signal.

Impedance(impedans) is the total electrical resistance to alternating current measured at a frequency of 1000 Hz. Typically the impedance of speaker systems is 4, 6 or 8 ohms.

In general, the value of the total electrical resistance (impedance) of an acoustic system will not tell the buyer anything related to the sound quality of a particular product. The manufacturer indicates this parameter only so that the resistance is taken into account when connecting the speaker system to the amplifier. If the speaker impedance value is lower than the recommended amplifier load value, the sound may be distorted or short-circuit protection will operate; if higher, the sound will be much quieter than with the recommended resistance.

Speaker housing, acoustic design

One of the important factors influencing the sound of an acoustic system is the acoustic design of the radiating dynamic head (speaker). When designing acoustic systems, the manufacturer usually faces the problem of choosing an acoustic design. There are more than a dozen species.

Acoustic design is divided into acoustically unloaded and acoustically loaded. The first implies a design in which the vibration of the diffuser is limited only by the rigidity of the suspension. In the second case, the oscillation of the diffuser is limited, in addition to the rigidity of the suspension, by the elasticity of the air and the acoustic resistance to radiation. Acoustic design is also divided into single and double acting systems. A single-action system is characterized by the excitation of sound traveling to the listener through only one side of the diffuser (the radiation from the other side is neutralized by the acoustic design). The double-acting system involves using both surfaces of the diffuser to produce sound.

Since the acoustic design of the speaker has virtually no effect on high-frequency and mid-frequency dynamic drivers, we will talk about the most common options for low-frequency acoustic design of the cabinet.

An acoustic scheme called a “closed box” is very widely applicable. Refers to a loaded acoustic design. It is a closed case with a speaker diffuser displayed on the front panel. Advantages: good frequency response and impulse response. Disadvantages: low efficiency, need for a powerful amplifier, high level of harmonic distortion.

But instead of having to deal with the sound waves caused by vibrations on the back of the diffuser, they can be used. The most common option among double-action systems is the bass reflex. It is a pipe of a certain length and cross-section mounted in a housing. The length and cross-section of the bass reflex are calculated in such a way that at a certain frequency, oscillations of sound waves are created in it, in-phase with the oscillations caused by the front side of the diffuser.

For subwoofers, an acoustic circuit commonly called a “resonator box” is widely used. Unlike the previous example, the speaker diffuser is not located on the housing panel, but is located inside, on the partition. The speaker itself does not directly participate in the formation of the low frequency spectrum. Instead, the diffuser only excites low-frequency sound vibrations, which then increase many times in volume in the bass reflex pipe, which acts as a resonant chamber. The advantage of these design solutions is high efficiency with small dimensions of the subwoofer. Disadvantages manifest themselves in deterioration of phase and impulse characteristics, the sound becomes tiring.

The optimal choice would be medium-sized speakers with a wooden body, made in a closed circuit or with a bass reflex. When choosing a subwoofer, you should pay attention not to its volume (even inexpensive models usually have sufficient reserve for this parameter), but to reliable reproduction of the entire low frequency range. In terms of sound quality, speakers with thin bodies or very small sizes are the most undesirable.