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Author's acoustic systems. Author's acoustics or traditional

Speakers are the main battlefield of manufacturers and the biggest topic of discussion for music lovers - because they contribute the most to sound quality...

… and it primarily depends on them whether the owner of the system will enjoy his favorite music every day, surprise his friends with its scale and naturalness, or use acoustics in the form of an expensive but not very useful accessory.

Different speakers do not play all genres of music equally well. Some do an excellent job with pop, rock and RNB, but completely refuse jazz and classical music. Others produce great vocals - and Rammstein sounds awful on them.

Omnivorous acoustics does not exist - either it is omnivorous, but it costs indecent money from the position of a sound mind ...

Speakers must be selected very carefully - and preferably for the musical tastes of the future owner, and their type and brand should be linked to a very specific amplifier, cables and room.

First of all, you need to pay attention to the size ...

Why do we need big speakers...

(Among audiophiles, there is an opinion that large speakers create a large and large-scale sound, and small ones create a small one ...)

Bass is the basis of any music, if it is not there, then the whole musical composition sounds flat and uninteresting.

If we omit the external finish and the shape of the case, then there is a tendency: the larger the internal volume of the speaker system, the better the bass ... You can’t get away from physics - low frequencies have a long wavelength and require a large amount of volume to reproduce them correctly.

(By analogy with cars, no matter how we manage to load three tons into an ordinary city sedan, nothing will work, for this we need at least a truck.) ...

While relative bottom end quality can be obtained from smaller speakers…

To do this, they use speakers with a heavy moving system and a large diffuser stroke. Such speakers have low sensitivity(efficiency) and for their normal operation powerful transistor amplifiers are needed.

... Large powers - high currents, as a result of large heating and loss of characteristics.

Low frequencies in such speakers are late in relation to vocals and are distinguished by noticeable viscosity. It turns out the effect of "breaking the sound." The same happens in home theater sets with powerful subwoofer and small satellites. You almost always hear that the subwoofer plays as if by itself - separately from the rest of the speakers ...

And the sound on any material, no matter whether it is music or the sound track of the film, should be solid - fused.

Compensation options for the small volume of speakers - labyrinths and phase inverters, do not affect the sound in the best way. When they are used, at low frequencies, humps and dips are noticeable to the ear.

Systems - consisting of small speakers and powerful transistor amplifiers - play well pop music, modern club styles, classic rock - and rather mediocre jazz and classics.

The lightest and most open sound is given Acustic systems"infinite volume" - when dynamic heads are built into the walls, and their rear volume is not limited by anything. Or speakers - which are large shields with built-in speakers. In terms of sound, shields are very similar to acoustics of infinite volume and greatly outperform "Box" acoustics.

Unfortunately, in real houses and apartments, these types of design are used very rarely - which is a pity ...

… With the joint design of housing and acoustics in it - a design such as a shield or an endless volume, it can be built into the room with little or no damage to its design. You just need to start this as early as possible, when there is concrete around - and not wallpaper and hanging curtains.

What's inside the speakers?

The sound depends very little on the appearance of the speakers - it depends on the quality of the dynamic heads, the volume and rigidity of the cabinet, the correct calculation of the crossover frequencies and the joining of the bands, the accuracy of the filter elements.

This multi-polar task is difficult for large-scale production. Acoustics is modeled and tuned once - this happens at the stage of manufacturing a prototype.

In contrast to the exterior finish - on the insides of the company, manufacturers usually - save...

Filter coils are wound with a thin wire - which introduces increased resistance

To reduce the cost of copper while maintaining the inductance of the coils, iron cores are inserted into them, which have a bad effect on the impulse response of the speakers

Copper, and especially silver, used in coils and filter capacitors, is mixed with iron in incomprehensible proportions to save money.

Resistors for filters are used inexpensive, usually cermet - low accuracy

Each dynamic head produced under conditions of large-scale production, in terms of characteristics and sound, is at least a little - but different from each other.

Nobody makes individual adjustment of columns.

The sound of serial acoustics, even expensive ones, can be significantly improved by adjusting the filters - by changing the elements in them to more accurate and high-quality ones. Replace stock internal wiring with audiophile cables. Install additional spacers inside the housings to increase the rigidity of the walls, add vibration damping material ...

There is where to turn around in the post-Soviet space, with its incredible reserves of ultra-pure copper and silver. What is very successfully used by domestic enthusiasts, improving branded speakers. Such a "custom" or handmade production of unique copies of not Harley Davidson motorcycles - but sound.

(By the way, many world-respected foreign manufacturers of audio wires often buy materials in the Urals or the Far East in Russia, where copper smelters still adhere to Soviet standards of purity and quality).

Author's acoustics are in great demand today. What kind of acoustics to choose in a car - so to speak, "solid", or author's, is often asked on forums and sites dedicated to the subject of car audio.

This is a fairly broad topic, common among music lovers. Author's acoustics can be built according to the base and traditions of the company, in most cases the sound is no worse than the original, and the design, sometimes even better.

All this cannot leave music lovers indifferent.

Author's acoustics and comparative review of components

thorny, which is tough enough only for car audio gurus. A lot should be provided here: independent, measurement, calculation and modeling, as well as much more, including final fine-tuning and settings;
Cheating or amateur. As a rule, this scenario is suitable for many. It can even be called acoustics for self-repetition.

speakers

Today, however, as always, speakers are the main battlefield for car audio manufacturers. It is they who are responsible for the sound quality, allow you to enjoy musical compositions, the naturalness of frequencies, scale, and so on.

Note. Proper, competent choice of speakers will allow you to get the maximum benefit from the speaker system. It's no secret that many owners use acoustic speakers in the car only as an expensive, but of little use accessory.

I would like to give a few important facts about speakers.

Every motorist who respects good music, should know about it:

Not all musical genres play equally well with different speakers. Some are perfect with pop music, others with rock or jazz compositions;
There is no omnivorous acoustics. If, nevertheless, it takes place, the price of the issue cannot be considered from the standpoint of common sense;
Selection acoustic speakers must be appropriate to the musical tastes of the future owner. Type, brand of speakers should also be linked to a specific amplifier, wiring, and so on;
Size matters. As a rule, most connoisseurs are on the side of big, huge speakers.

The last point deserves a separate, closer attention.

Benefits of large speakers

There is an opinion that huge speakers create a larger sound. Accordingly, small - small.

To all lovers good sound It is known that the basis of any music is the bass. In its absence, it simply does not make sense to talk about the quality of a musical etude.

Note. The size of the speakers directly affects their bass. Ignoring the design and shape of the speaker cabinet, we trace a certain trend: the larger the internal space of the speaker, the better the bass. This is a law of physics, from which there is no escape - the larger the volume, the more at ease low frequencies that have a longer wavelength feel.

On the other hand, relatively acceptable bass quality can also be obtained from small speakers if a heavy moving system is introduced and the cone is given more stroke. True, such speakers will have low efficiency, but this is not a problem if you integrate them with non-weak transistor amplifiers.

In addition, manufacturers compensate for the power on small speakers with all sorts of labyrinths and phase inverters, which affects the sound negatively. So, in this case, humps and dips appear on the bass, which are easily distinguishable by ear.

So, systems with small speakers and the right amplifiers do a good job with classic rock, rather mediocre with jazz compositions and classics, but play pop music perfectly.

You can make a homemade version that gives an almost perfect sound. These are the so-called speakers of "infinite volume", implying the built-in emitters in the walls and unlimited, open rear volume.

Note. It can even be simple wooden shields in which speakers are installed.

Column content

The sound quality depends most of all on what is inside the speaker. Correct calculation is important.

Many manufacturers, especially little-known and not well-known ones, often go the shaky way, saving on the internal equipment of the speakers. Appearance, design of such speakers, as a rule, does not cause disapproval. Needless to say, it is not recommended to do this when creating author's acoustics.

In particular, here's what they save on:

The main savings affect the winding of the filter coil. In this case, it is made of a thin wire that introduces increased resistance;
Also, to reduce the cost of copper, iron-type cores are inserted, which negatively affect certain characteristics;
Cheap cermet resistors are used, which are characterized by low accuracy;
There is no customization for individual requests.

Traditional or author's

It turns out that following the amateur path, you can significantly improve the performance of branded acoustics by amending it and changing the settings. But such acoustics can rightly be called the author's.

Here are some improvements you can make:

Adjust filters by changing the internal components to more productive and accurate ones;
Replace cables to more expensive ones
Install additional spacers inside speaker cabinets for improved rigidity;
Upgrade traditional speakers, using Soviet-style acoustics, which involve an incredible amount of pure copper and even silver.

Note. By the way, some branded manufacturers (including quite successful ones) often buy materials to create their own acoustics at Russian copper smelters, where the old canons of quality are still in force. For example, there are many such factories in the Urals.

Understanding which acoustics is better to put in a car (see), branded (albeit individually modified) or purely author's is not so easy. This is not a comparison of Vertu's phone and its cheap copy.

But you should know that 90 percent of the horn speakers known to this day are copyrighted. In addition, the best acoustic systems are created on the basis of author's developments, which, one way or another, says a lot.

Fostex was founded in 1973. It is a subsidiary of Foster Electric Co., Ltd., one of the world's leading manufacturers of loudspeaker equipment, as well as devices for converting and transmitting sound. The company has offices in 9 countries and employs more than 20,000 people. Shares of Foster Electric Co., Ltd. listed on the Tokyo Stock Exchange.
Fostex was originally formed to sell loudspeaker components to consumers and dealers in Japan (in that country a large number of ordinary people design and build home speakers of their own design, even today component sales account for the majority of the company's Japanese income).
It should be noted that Fostex was one of the first to develop and implement RP (Regularphase) technology, which provides very clear sound with high sensitivity and wide dynamic range, which immediately won consumer approval and world fame.

The speakers of this company are very popular among electroacoustics due to their good price / quality ratio among broadband speakers and were recommended to me by one of my main mentors, comrade Alexander from Kharkov, who made more than a dozen speaker systems, respectively, had tremendous experience in selecting speakers.
During the manufacture of one of my two-way speaker projects on Visaton W200 and Vifa XT25TG in the design of a quarter-wave tube (TQWP), my friends were offered a pair of FostexFE206En at a very attractive price. Unable to resist the long-standing temptation to listen to horn acoustics, and even on the Fostexes themselves, it was decided to change priorities.
Measurements of the Thiel-Smol parameters showed a similarity with the factory ones within 5%, which most speakers even from such companies as Vifa, Visaton, Seas, etc. cannot boast of.
Externally, the speakers turned out to be very unusual on the one hand, but at the same time very logical and rational solutions for absolute sound quality, on the other hand, a massive magnet (diameters more than 12 "woofer 150GDN from Cleaver 75AC), soft textile suspension and flexible centering washer, a lightweight cone made from banana wood fibers and the presence of an even lighter composite film on the dust cap (used as material for dome tweeters) for better playback high frequencies made it possible to achieve a sensitivity of 96 dB / 1 W / m, with the prospect of using it in a horn design and great option For tube amplifier.
The concept of a single-band speaker is very tempting due to the presence of certain advantages over multi-band counterparts.
Among the advantages, it is worth highlighting the absence of phase mismatch and time delays that occur due to corrective filters, different distance between the speakers as well as a different acceleration factor (the mass of the moving system, for example, in two-way speakers, when you need to dock a heavy woofer with a light tweeter, a threshold occurs at the crossover frequency), which brings its own unwanted distortions. Therefore, the sound of this acoustics is characterized by a special solidity and saturation.
Another clear advantage broadband systems is a careful selection of materials for the moving speaker system for maximum bandwidth, which makes it possible to use them in exotic and most authentic designs, in particular the return horn

(voigt quarter-wave trumpet) TQWP

ONKEN

labyrinth

When viewing the characteristics of the speakers in the passport, we see the recommended drawing of the reverse horn body. However, his uncouth appearance makes you look for other design solutions.

Luckily, there are several more attractive designs for these speakers on the shelves of the speaker store and disinterested electro-acoustics. For example:

Using one of the drawings provided, we can achieve a maximum lower playback limit of 75Hz. However, the size of the room and the desire for the best possible results allow us to make large cabinets, which will allow us to achieve the maximum possible bass depth. The calculation of the horn and the modeling of the frequency response is carried out in free program HornResp, which allows you to simulate the behavior of the frequency response in a horn design according to the Thiel-Smol parameters, the volume of the pre-horn chamber and the structural features of the horn.
According to the theory of the horn design of loudspeakers, in order to achieve maximum depth in the lower register (sacrifice of greater efficiency), it is necessary to strive for the maximum length of the horn, and the maximum mouth area at the exit, while not forgetting to observe the golden ratio 1/3 (mouth / mouth). According to various sources of information, the pre-shock chamber should be equivalent to the volume of the design of a closed box or phase inverter. In our case, this is 20 liters for a phase inverter and 10 liters, respectively, for a closed box. According to the selected drawing, the volume of the pre-horn chamber was 7 liters, which is not acceptable in our case, so it was decided to improve the drawing by increasing the volume of the pre-horn chamber to 12 liters, expandable up to 17 liters with a baffle. The updated drawing looked like this:

The body is made of 20mm chipboard, the choice of color was stopped at dark oak Wenge. Bright room and White color dynamics at the same time created excellent contrasts. Due to the fact that the labyrinth inside the acoustics additionally played the role of partitions, the cases practically did not need vibration absorption. Moreover, the slightest change in the shape, cross-section of the horn, as well as the spacers inside the labyrinth, brought significant distortion at medium frequencies and created a distortion in the scene. Some large manufacturers and ordinary horn speaker designers recommend using a small amount of absorber in the pre-horn chamber, especially if it is small, placing the absorber directly on the wall of the pre-horn chamber behind the speaker and not covering the mouth of the horn. In subjective evaluation after sound absorption, there was a noticeable deterioration in bass articulation, excessive suppression of mid frequencies (even with the minimum size of a piece of sound absorber in the form of foam rubber, felt, mineral wool). Therefore, I recommend using a sound absorber only in exceptional cases, when the humps of the frequency response are too large or standing waves or bursts of the frequency response of the speakers are problematically corrected by notch filters.
After assembling the body and the first test listening, there was an acute lack of depth in the lower register. The reason for this was the insufficient sealing of the horn labyrinth partitions and the housing walls. Having eliminated air leaks with a sealant, and glued the removable side wall with a sealant, it was possible to achieve a much better result.

The final sealing step was carefully sealing the speaker seat with a thicker rubber seal. The result exceeded expectations, and it was even possible to achieve an excess of bass, but not its depth. More volume meant more bass depth, but less pressure, which was a great corrector in our situation.
When measuring frequency response and speaker impedance

in the speaker system, a burst of frequency response was found at a frequency above 12 kHz and a low-quality, insignificant presence at a frequency of 3.49 kHz. The first is corrected by a compensating Zobel circuit, the second by a parallel low-Q notch filter.
The inductor should be wound with a wire with a cross section of at least 1.2 squares so that its reactance does not exceed 0.5 ohms, otherwise there will be noticeable losses in depth and bass articulation.
Fostex speakers have a very light sound, which perfectly convey instrumental music, vocals. The paper cone and horn design give a neutral sound, with a slight splash in the upper mids and lower highs. Therefore, it is necessary to keep the original timbre of the speakers as close as possible and make a small dip in the upper middle region. Since all types of coupling capacitors have a unique timbre, this should be taken into account when choosing the type of bypass capacitor in the notch filter.
The following capacitors were tested:
-Metal-paper MBGOs: Almost neutral timbre with little presence in the low-mids, and lack of high frequencies.
- Metal-paper MBGCH, with extended upper treble range: Too raw sound with muffled mids and excessive high frequencies.
- MBM metal-paper capacitors: rather sonorous sound due to harmonics in the upper middle, distortion of the localization of sound images when building a scene of audio compositions.
- metal film K-73-17: neutral sound, excessive suppression of the upper middle.
-metal film K-73-11: neutral sound, excessive suppression of the lower HF register.
The choice was stopped on the metal-film K-73-11, as the most suitable for the features of the timbre of our speaker.
Wiring to the acoustic terminal should be carried out as symmetrically as possible in the center of the horn, attaching it to the wall and setting the maximum tension.

The expectation of listening was justified and left many unforgettable impressions in the first seconds. It was not possible to confine ourselves to a minimum test set of compositions to establish an assessment of listening to this acoustics. On the contrary, an insatiable desire appeared to listen to audio compositions of various genres, which actually was done.
Among best qualities it is worth highlighting a much broader focus, and the best elaboration and greater reliability of the lower register of all existing speaker designs.
Instrumental audio compositions - classical, light rock, jazz - are reproduced most reliably and with high quality. Just as well articulated and powerful lower register plays pop, rap, etc. up to dubstep. However, heavy rock and these acoustics reproduce with some drawbacks.
After constructing this acoustics, a weak link in the remaining sound path began to be felt - sound card Asus Xonar DX. Discrete transistor amplifier The Harman Kardon PM 655 is up to the task, but these high-sensitivity speakers with lightweight drivers will further unleash their potential when paired with a tube amplifier.
And of course, after numerous listenings, you come to the desire to abandon such low-frequency designs as a closed box, a phase inverter, and even a Voight quarter-wave tube due to a clear loss in the reliability of audio composition reproduction.
Therefore, as a design in multi-band speakers and subwoofer systems, if possible, I recommend using horn design.
I wish everyone good luck in designing horn speakers and a possible repetition of my project!

5.0 system for listening in conjunction with a subwoofer.

I would like to present to your attention a recently manufactured 5.0 system based on loudspeakers manufactured in the USSR. First of all, I want you to get acquainted with the history of the development of acoustic systems and give some recommendations on choosing the type of speakers.

It all started a long time ago with the simplest speaker built into the case. This "device" was called a speakerphone, by the way, it is now a mandatory attribute of any "shell". The situation changed with the advent of the first sound cards that could provide 2-channel audio output. Now this system is called "scientifically" 2.0 (the first digit is the number of speakers, the second is the number of subwoofers), but earlier they said it was simpler - a stereo system.
The first multi-channel acoustic systems had the designation 4.0, which, respectively, included 4 speakers - two front and two rear. Such acoustics gives good effects in games, creating a three-dimensional sound. With the help of the 4.0 system, you can, of course, listen to music, but the sound will not differ much from that which can be obtained on the usual two speakers. In 4.1 acoustics, as the name implies, a subwoofer has been added. True, these systems still remained four-channel - low-frequency signals in them are distinguished using a special crossover.

The next type of speakers already has a full 6-channel sound. We are talking, as you probably already guessed, about 5.1 acoustics. These kits include two front speakers, two rear speakers, one center speaker and a subwoofer. That is, compared with 4.1 acoustics, a central emitter appeared. And you need it to match the Dolby Digital format often used in films, especially on DVDs. The dialogues of the characters are transmitted through the central column. In addition, 5.1 acoustics can be equipped with DTS and Dolby Pro Logic decoders. Thus, 5.1 systems are the minimum required for a home theater.

Pains of choice...

2.0 and 2.1. Most computer users are not very picky about computer sound. If you listen to mp3 recordings, and even sometimes play, then acoustics 2.0 or 2.1 will be enough for you. Moreover, if you want to achieve quality sound then just buy a more expensive system. It makes no sense to buy more "advanced" acoustics, since it requires a multi-channel sound card. And such expenses for listening to mp3 (a format that does not differ in special sound quality) seem irrational to me.
4.0 and 4.1. This acoustics is intended first of all for players, and especially for fans of three-dimensional "shooters". Especially for 4.0 and 4.1 systems, game developers create impressive sound effects that can significantly cheer up players. Well, when listening to music on 4.0 and 2.0 systems, you will hardly feel the difference, since in most cases the rear speakers will simply duplicate the signal from the front ones. Thus, when buying good acoustics 2.0 or 2.1, you can listen to better music than after purchasing acoustics 4.0 or 4.1 of the lower price range.
5.1. As I said, the 5.1 format was developed primarily for watching movies on DVD and blu-ray quality. Thus, if you often watch videos on your computer, then the choice is clear for you. In addition, 5.1 acoustics gives very good results when listening to music. In games, it all depends on whether the developers have bothered to provide support for 6-channel sound. If not, then the use of acoustics 5.1 and 4.1 will not differ much.

This speaker system has been designed with the following requirements in mind:

1) The width and height of the case was determined by the installation of speakers in decorative niches. Therefore, to compensate for the insufficient size of the speakers, for example, in height, it was possible to use depth dimensions.

2) Sharing and alignment with active subwoofer on a 12" head with an upper cutoff frequency of not more than 110 Hz from Mission M6AS

3) A fairly modest budget in which to invest.

This led to some difficulties, since the development of acoustic systems usually begins with the selection of the volume and shape of the speakers for the parameters of a particular speaker. In addition, the dynamics of the production of the USSR, with their lightness and richness of sound, had an excessive quality factor, which made it impossible to listen to them even in the design of a "closed box" - a large uneven frequency response and, as a result, a heavy and mushy sound. For reference: the design of an open box can be performed in the following options:

1) The absence of a rear wall in the speaker system.

2) Use instead of it a sound-absorbing material stretched over the entire area, I experimentally select the thickness and material.

3) Using a perforated back wall, such as here:

However, the trade-off for "smooth frequency response" is a sharper rolloff much farther from the main resonance frequency in the bass region. due to "acoustic short circuit front and rear of the speaker cone.

The way out of this situation was to use the second subwoofer in the frontal and most critical speakers. This made it possible to reduce the lower limiting playback frequency to 90 Hz and improve the radiation pattern of the audio system.
You can compare the frequency response graphs - the upper open box, the lower one is closed.

The choice of speakers for acoustic systems due to the high cost of imported speakers, the presence of fakes and Chinese copies was stopped at domestic ones, made in the USSR. They are very much appreciated in the circles of audiophiles, lovers of tube and vintage sound. Of the advantages, you can consider:

affordable price;

High sensitivity (it is undemanding to power - - the amplifier and an ideal variant for tube);

Big potential.

I will dwell on the latter in more detail. Broadband speakers of domestic production had a very pleasant timbre, simply chic and enviable for so many foreign analogs of micro-speakers, and sound detailing, a wide stage and lightness of sound. This was achieved due to the absence of vibration and sound absorbing mastics in the manufacture of the cone. Of course, there were no casualties. Now we can highlight the main disadvantages:

Too uneven frequency response due to excessive quality factor and the absence of mastics, which I use to eliminate the above disadvantages from imported manufacturers of dynamic heads;

Pretty nondescript appearance of mostly all the speakers, especially the basket, because of which you have to resort to non-standard solutions like positioning the speaker from the inside of the case or using grills and decorative rings to hide these shortcomings. The choice settled on 8 "8gdsh-1 for LF / MF link in front and rear speakers

and 6" 5gdsh-4 for the center channel.

As a high-frequency link, the legendary oval diffuser type 3gdv-1 was used, which give a velvety timbre to the sound of speakers, unlike dome tweeters.

However, the sheepskin is worth the candle. The inherent potential can be unlocked thanks to the long and painstaking work on the calculation and adjustment of crossover filters, which took the lion's share of the time in the manufacture of these speakers.

To recreate the correct sound picture in a 5.1 system, the rear speakers must not only be located at a level slightly above the listener's head, but also be directed strictly at the listener. To do this, I use consoles (brackets) with vertical and horizontal tilt angles. However, there is a problem: they must be attached to the rear wall of the speakers, which we don’t have ... Here, we had to sacrifice the appearance of the upper wall of the speakers, fixing them with 2 bolts and slightly modernizing the brackets for mounting to the top of the speaker system.
to secure them from the inside. An attempt to search for CNC machines for milling in the city was not successful, so I had to mill it manually using a template. However, after the work done, irregularities and chips from the decorative film were revealed. The protective grill grill not only did not give a better appearance, but also worsened the appearance of the joints of the grill with the chipboard body.

For an objective assessment of the sound, the opinion of audio critics is necessary. Immediately a committee of critics was formed from relatives and friends. Most of them are simply indifferent to music. And only 2 of them are musicians.
Test compositions were selected concert Nigtwish Dark Parsons Play 2008 recorded in DTS-HD Master audio 5.1 and 2.0. 24Bit 48KHz with and bitrate audio 5400 kbps and gigMetallica: Orgullo pasion y Gloria - Tres Noches en Mexico 2009 with format audio trackDTS-HD Master audio 5.1 and 2.0. 24Bit 96KHz with 7200 audio bitrate kbps / second .
When listening to the 5.0 system for the first time, a clear localization of objects was noted, a large-scale stage with an evenly distributed sound field, chic microdynamics, the play of each instrument is clearly audible, and most importantly, the reproduced sound images are not tied to the speaker system, but are evenly distributed in the recreated powerful scene. Even when listening to these live tracks and other Flac single tracks(uncompressed audio codec, as good as a licensed CD)and watching the trailer for the film Transformers: The dark side of the moon, a very interesting phenomenon was observed: the stereo pair gave such an extensive scene that even in an acoustically imperfect room, objects were localized even to the side of the listener and even behind the speakers, which was a very pleasant surprise and put an end to doubts about the correct manufacture and tuning of the speakers.