Many fans of horn acoustics became acquainted with it back in the days of classic speakers. For every music lover, the integrity of perception and the natural sound of the overall sound picture are much more important than the reproduction of individual sounds. Horn acoustics (English name Acoustic Horn) are famous for their high degree of realism, presence effect and outstanding dynamics. High-quality horn acoustics have the ability to capture and surprise the listener. Many advanced audiophiles seek to improve the quality of their speaker systems.
The main differences between horn acoustics and all others
The horn loudspeaker has a high efficiency rate, which allows it to be used in high-level audio systems. But the most important difference between highly sensitive horn systems and all others is the large dynamic range, wide and linear amplitude-frequency response of the loudspeakers.
Excellent efficiency allows high sound pressure levels to be achieved even when using low-power amplifiers. It is possible to use this type of acoustics with amplifiers of various designs. It can be transistor amplifiers, tube amplifiers, amplifiers on chips.
Owners of rare amplifiers with unique circuitry made using electric tubes will be able to use their existing acoustic equipment to full capacity. Improving acoustics can be an ongoing and extremely fun process.
If you decide to purchase horn acoustics
When planning the purchase of acoustic speakers, you should remember that the difference between the quality of “bad” and “good” horn speakers will be much more pronounced than the difference between the quality of acoustics with a traditional design.
There is a misconception that this type of speaker can color the sound. This is far from true. It’s just that in some cases, low-quality acoustic systems are used that do not provide the proper sound.
According to experts, horn speakers equipped with Alnico magnets today have the best quality.
Such products have a fairly high cost, which is determined by the complexity and high cost of their production. Speaker charts can be made from exotic metals. Such technology will not accept the strategy of reducing costs and compromises.
To better understand prices, we will give an example of the cost of the components used. For example, a two-inch TAD compression driver, used in all high-quality Acoustic Horn Cessaro systems, costs about a thousand euros. The most expensive tweeter with a beryllium diaphragm costs about $600.
It is not surprising that Acoustic Horn Hi-End class have a fairly high price. Horn speaker manufacturers make true works of art. Some models are produced in limited editions, which are popular and respected by true connoisseurs of high-quality sound.
For example, the Japanese company producing Acoustic Horn Maxonic, which appeared in 1932, is widely known. Today, acoustics from Maxonic are super modern products that use exclusively expensive components and technologies. One of the developments of this company is the magnetization of systems using active magnets. This technology has no analogues on the market.
One way to increase output is to use horns. Remember the ancient gramophones: thanks to the horn, small vibrations of the needle connected to the membrane created a very loud sound. In gramophones, part of the horn is folded and “hidden” inside the body. The open lid serves as a sound reflector. Horn loudspeakers are used for sounding open areas. A professional horn loudspeaker can have an efficiency of up to 25-35%. A good horn loudspeaker is hardly available to radio amateurs, but something can be made from ordinary heads.
Of the ones available to the author, good results were shown by a small-sized industrial speaker in a narrow and deep plastic case with one 1GD-40 head. Its output, quite large and without additional measures, was noticeably increased by a folding horn (Fig. 3.4), made from cardboard folders for papers. The radiation from the rear of the driver cone, emerging from the open rear of the speaker, is reflected from the middle part of the horn speaker system and directed by its expanding side walls towards the listener. The system is also covered with cardboard covers at the top and bottom.
Another folding horn acoustic system can be easily made from an old “diplomat” with hard fiber walls (soft ones absorb sound). The design (side view) is clear from Fig. 3.5. Two elliptical heads 1 (for example, 1GD-40) are fixed in one line on a narrow reflective board 2 located in the front of the suitcase. The horn system is formed by the bottom and a slightly curved plastic panel 3. The gaps formed at the side walls must be closed. Coming out of the wide rectangular opening, the sound is reflected by the open cover of the suitcase 4, towards the listener, and combining with the sound emitted by the front side of the diffusers. For better reflection, “acoustic mirrors” 5 made of plastic are installed near the hinges. There is enough space left in the “diplomat” to accommodate an output transformer, receiver and other useful things.
A wide-neck bass reflex is sometimes made in the form of a “horseshoe”, which was described above, or a “labyrinth”. Both designs are shown in Fig. 3.6, and the front view (along A) is almost the same - on top is the hole for the head, on the bottom is the outlet hole of the horn. The side walls can be made vertical, but better - expanding towards the horn opening. We do not give dimensions because they are not critical. With a sound wave path length inside a “horseshoe” or “labyrinth” of the order of a meter, one should expect reproduction of lower frequencies up to 70-100 Hz. Of course, these speakers can also be placed horizontally, combining them, for example, with a bookshelf.
Matching transformers have already been mentioned in the previous section. Where should it be installed, in the receiver or in the speaker? The answer is clear - only in the speaker system, otherwise losses in the connecting wires can significantly reduce the efficiency. For example, if the resistance of the wires from the receiver to the four-ohm speaker is only 1 Ohm, the efficiency will be 80%. By increasing the input impedance of the speaker to 4-10 kOhm with a transformer, we get 100% efficiency and the ability to use thin wires. But a blocking capacitor must be installed in the receiver, since it closes the high-frequency currents of the detector. If the speaker sizes are still large, it is better to use “solid” transformers - they have less losses. TVK and TVZ from old TVs are suitable. Their approximate data: core cross-section 2.5-3 cm 2, primary winding - 3000 turns of 0.15 PEL, secondary - 100 turns of 0.7 PEL. You can also use “power units” - network transformers of power supplies with a transformation ratio of 220/6-12.
Fostex was founded in 1973. It is a subsidiary of FosterElectricCo., Ltd., one of the world leaders in the development of equipment for acoustic systems, as well as devices for converting and transmitting sound. The company has offices in 9 countries and employs more than 20 thousand people. Shares of Foster Electric Co., Ltd. listed on the Tokyo Stock Exchange.
Fostex was originally created to sell speaker components to consumers and dealers in Japan (in this country, a large number of ordinary people design and create home speaker systems of their own design; even today, the sale of components accounts 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 a wide dynamic range, which immediately won consumer approval and world fame.
The speakers of this company are widely popular among electro-acoustic speakers 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 manufactured more than a dozen speaker systems and, accordingly, had enormous experience in selecting speakers.
During the production of one of my projects - a two-way speaker on a Visaton W200 and Vifa XT25TG in the design of a quarter-wave voyage pipe (TQWP), my friends were offered a pair of FostexFE206En at a very tempting price. Unable to resist the long-standing temptation to listen to horn acoustics, and even on the Fostex themselves, it was decided to change priorities.
Thiel-Smol's parameters measurements showed 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 with very logical and rational solutions for absolute sound quality on the other hand - a massive magnet (more in diameter than that of a 12" woofer 150GDN from Cliver 75AS), a soft textile suspension and a flexible centering a washer, a lightweight diffuser made from banana tree fibers, as well as the presence of an even lighter composite film on the dust cap (used as a material for dome tweeters) for better reproduction of high frequencies allowed us to achieve a sensitivity of 96 dB / 1 W / m, with the prospect of using it in horn design and an excellent option for a tube amplifier.
The concept of a single-way speaker is very tempting due to the presence of certain advantages over multi-way analogues.
Among the advantages, one should highlight the absence of phase mismatch and time delays that occur due to correction filters, different distances between speakers, as well as different acceleration factors (the mass of the moving system, for example, in two-way speakers, when you need to connect a heavy woofer with a light tweeter, a threshold arises at crossover frequency), which brings its own unwanted distortions. Therefore, the sound of these acoustics is characterized by a special solidity and richness.
Another clear advantage of wideband systems is the careful selection of materials for the moving speaker system for maximum broadband, which makes it possible to use them in exotic and most reliable designs, in particular a reverse horn
(quarter wave voight tube) TQWP
ONKEN
According to the theory of horn design of loudspeakers, in order to achieve maximum depth in the lower register (at the sacrifice of greater efficiency), it is necessary to strive for the maximum length of the horn, and the largest possible mouth area at the output, while not forgetting to observe the golden proportion of 1/3 (neck/mouth) . According to various sources of information, the pre-horn camera should be equivalent to the volume of a closed box or bass reflex. In our case, this is 20 liters for a bass reflex 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, with the possibility of increasing up to 17 liters using a partition. The modernized drawing looked like this:
After assembling the case and the first test listening, there was an acute lack of depth in the lower register. The reason for this was insufficient sealing of the partitions of the horn labyrinth and the walls of the housing. By eliminating air leaks with sealant and pasting the removable side wall with sealant, we were able to achieve a much better result.
When measuring the frequency response and impedance of the speaker
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 the depth and articulation of the bass.
Fostex speakers have a very light sound that perfectly conveys instrumental music and vocals. The paper cone and horn design gives a neutral sound, with a slight splash in the upper mids and lower treble register. Therefore, it is necessary to preserve the original sound timbre of the speakers as closely as possible and make a small dip in the upper middle area. Since all types of coupling capacitors have a unique timbre, this should be taken into account when choosing the type of pass capacitor for a notch filter.
The following capacitors participated in the test:
-Metal paper MBGO: almost neutral timbre with slight presence in the lower mids, and a lack of high frequencies.
-Metal paper MBGCH, with an extended upper range of high frequencies: Too raw sound with a muted midrange and excessive high frequencies.
- MBM metal paper capacitors: rather ringing sound due to harmonics in the upper middle, distortion of the localization of sound images when constructing a scene of audio compositions.
- metal film K-73-17: neutral sound, excessive suppression of the upper mids.
-metal film K-73-11: neutral sound, excessive suppression of the lower high-frequency register.
The choice was made on metal film K-73-11, as the most suitable for the timbre characteristics of our speaker.
Installation of wiring to the acoustic terminal should be done as symmetrically as possible in the center of the horn, attaching it to the wall and setting the maximum tension.
The wait for the audition turned out to be justified and in the first seconds it left many unforgettable impressions. It was not possible to limit ourselves to a minimum test set of compositions to establish an assessment of listening to these acoustics. On the contrary, an insatiable desire appeared to listen to audio compositions of various genres, which was actually done.
Among the best qualities, it is worth highlighting a much wider focus, and the best elaboration and greater reliability of the lower register of all existing speaker designs.
The most reliable and high-quality reproduction of instrumental audio compositions is classical, light rock, jazz. Also, a well-articulated and powerful lower register plays pop, rap, etc. up to dubstep. However, this acoustics reproduces hard rock with some drawbacks.
After constructing this acoustics, the weak link of the remaining sound path began to be felt - the AsusXonar DX sound card. The discrete transistor amplifier HarmanKardon PM 655 still copes with the task, but these highly sensitive speakers with lightweight speakers will further reveal their potential in a duet 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 bass reflex and even Voight’s Quarter-Wave Tube due to the obvious loss in the reliability of the reproduction of audio compositions.
Therefore, when possible, I recommend using a horn design as a design for multi-band speakers and subwoofer systems.
I wish everyone good luck in designing horn speakers and the possible repetition of my project!
5.0 system for listening with a subwoofer.
I would like to present to your attention a recently manufactured 5.0 system based on speakers 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 speaker.
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 still a mandatory attribute of any “shell.” The situation changed with the advent of the first sound cards, which could provide 2-channel audio output. Now this system is called “scientifically” 2.0 (the first number is the number of speakers, the second is the number of subwoofers), but earlier they said it more simply - a stereo system.
The first multi-channel speaker systems were designated 4.0, which, accordingly, included 4 speakers - two front and two rear. Such acoustics give good effects in games, creating three-dimensional sound. Using the 4.0 system, you can, of course, listen to music, but the sound will not be much different from what you can get on regular two speakers. In 4.1 acoustics, as the name suggests, a subwoofer is added. True, these systems still remain four-channel - low-frequency signals are isolated in them using a special crossover.
The next type of speaker system already has 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 to acoustic 4.1, a central radiator has appeared. And it is needed to comply with the Dolby Digital format, often used in films, especially on DVDs. The central column conveys the dialogues of the characters. 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.
The agony of choice...
2.0 and 2.1. Most computer users are not very demanding when it comes to computer sound. If you listen to mp3 recordings and sometimes play, then 2.0 or 2.1 acoustics will be quite enough for you. Moreover, if you want to achieve high-quality sound, then simply buy a more expensive system. There is no point in purchasing more “advanced” acoustics, since they require a multi-channel sound card. And such costs for listening to mp3 (a format that does not have any special sound quality) seem irrational to me.
4.0 and 4.1. This acoustics is intended primarily for gamers, and especially for fans of 3D shooters. Especially for systems 4.0 and 4.1, game developers create impressive sound effects that can significantly lift the mood of 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 purchasing good 2.0 or 2.1 acoustics, you can listen to higher quality music than after purchasing 4.0 or 4.1 acoustics from the lower price range.
5.1. As I already 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 for you is clear. In addition, 5.1 acoustics give very good results when listening to music. In games, everything depends on whether the developers bothered to provide support for 6-channel sound. If not, then the use of 5.1 and 4.1 acoustics will differ little.
This speaker system was developed taking into account the following requirements:
1) The width and height of the cabinet were determined by the scope of installation of the speakers in decorative niches. Therefore, it was possible to compensate for the insufficient size of the speakers, for example in height, by using depth dimensions.
2) Sharing and coupling with an active subwoofer on a 12" head with an upper cutoff frequency of no more than 110 Hz from Mission M6AS
3) A rather modest budget to invest in.
This led to some difficulties, since the development of acoustic systems usually begins with selecting the volume and shape of the speakers to match the parameters of a specific speaker. In addition, the speakers produced in the USSR, with their lightness and richness of sound, had excessive quality factor, which is why it turned out to be impossible to listen to them even in a “closed box” design - a large uneven frequency response and, as a result, a heavy and mushy sound. For reference: the design of an open box can be done in the following options:
1) Absence of a back wall in the speaker system.
2) Using instead a sound-absorbing material stretched over the entire area; I experimentally select the thickness and material.
3) Use a perforated back wall, such as here:
However, the price for a “smooth frequency response” is a sharper decline much further from the main resonance frequency in the low-frequency region. due to an “acoustic short circuit” between the front and rear of the speaker cone.
A way out of this situation was found in the use of a second low-frequency speaker in the front and most important speakers. This made it possible to reduce the lower limit playback frequency to 90Hz and improve the radiation pattern of the acoustic system.
You can compare the frequency response graphs - the top box is open, the bottom box 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 settled on domestic ones, made in the USSR. They are highly valued in the circles of audiophiles, lovers of tube and vintage sound. Among the advantages you can consider:
affordable price;
High sensitivity (undemanding to the power of the amplifier and ideal for a tube amplifier);
Big potential.
I will dwell on the latter in more detail. Wideband speakers of domestic production had a very pleasant timbre, simply chic and enviable microdynamics and detail in sound for many foreign analogues, 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 diffuser. Of course, there were some casualties. Now we can highlight the main disadvantages:
Too uneven frequency response due to excessive quality factor and lack of mastic, which is used by imported dynamic head manufacturers to eliminate the above-mentioned shortcomings;
The appearance of most of the speakers, especially the basket, is rather unprepossessing, which is why you have to resort to non-standard solutions such as placing the speaker from the inside of the case or using grill grilles and decorative rings to hide these shortcomings. The choice settled on 8" 8gdsh-1 for the bass/midrange of the front and rear speakers
and 6" 5gdsh-4 for the central channel.
The legendary oval diffuser type 3gdv-1 was used as a high-frequency link, which gives a velvety timbre to the sound of the speakers, unlike dome tweeters.
However, the game is worth the trouble. The inherent potential can be revealed thanks to long and painstaking work on calculating and setting up the separation 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 angles of inclination. However, there is a problem: they must be attached to the back wall of the speaker, which we don’t have... Here we had to sacrifice the appearance of the top wall of the speaker, securing 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 by milling in the city was not successful, so I had to mill it manually using a template. However, after the work was done, irregularities and chips from the decorative film were revealed. The protective grill grille not only did not give the best appearance, but also worsened the appearance of the joints of the grille with the chipboard body.
To objectively evaluate the sound, the opinion of audio critics is necessary. A panel of critics consisting of relatives and friends was immediately created. Most of them are simply indifferent to music. And only 2 of them are musicians.
The test compositions were the Nigtwish Dark Parsons Play concert from 2008, recorded in DTS-HD Master audio 5.1 and 2.0 format. 24Bit 48KHz with audio bitrate 5400 kbps and concertMetallica: Orgullo pasion y Gloria - Tres Noches en Mexico 2009 with audio track formatDTS-HD Master audio 5.1 and 2.0. 24Bit 96KHz with audio bitrate 7200 kbit/second.
When we first listened to the 5.0 system, we noticed a clear localization of objects, a large-scale stage with an evenly distributed sound field, excellent microdynamics, the playing of each instrument was clearly audible, and most importantly, the reproduced sound images are not tied to the acoustic system, but are evenly distributed in the recreated powerful scene. Even when listening to these concert soundtracks and other single tracks in Flac format(uncompressed audio codec, quality is not inferior to 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 provided such a vast scene that even in a non-ideal room from an acoustics point of view, 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 configuration of the speakers.
Speakers are the main battleground for manufacturers and the most widely discussed topic among music lovers - because they make the greatest contribution to sound quality...
... and it primarily depends on them whether the owner of the system will enjoy his favorite music every day, surprise friends with its scale and naturalness, or use acoustics in the form of an expensive but little useful accessory.
Different speakers do not play all genres of music equally well. Some people do an excellent job with pop, rock and RNB, but completely refuse jazz and classical music. Others reproduce vocals superbly - but Rammstein sounds disgusting on them.
Omnivorous acoustics do not exist - either they are omnivorous, but cost indecent money from the standpoint of a sane mind...
You need to select speakers especially carefully - and preferably according to the musical preferences 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...
(There is an opinion among audiophiles 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 absent, then the entire musical composition sounds flat and uninteresting.
If we ignore the external finish and shape of the case, then a trend can be traced: the larger the internal volume of the speaker system, the better the bass... You can’t escape physics - low frequencies have a long wavelength, and a large volume is needed 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.)…
Although relative bass quality can be obtained from small speakers...
To do this, they use speakers with a heavy moving system and a large diffuser stroke. Such speakers have low sensitivity (efficiency) and require powerful transistor amplifiers for their normal operation.
... High powers - high currents, as a result of high heating and loss of characteristics.
Low frequencies in such speakers are delayed in relation to vocals and have a noticeable viscosity to the ear. This produces a “sound breaking” effect. The same thing happens in home theater sets with a powerful subwoofer and small satellites. You almost always hear that the subwoofer plays as if on its own - separately from the other speakers...
And the sound on any material, no matter if it’s music or the sound track of a film, must be integral - unified.
Options for compensating for the small volume of speakers - labyrinths and bass reflexes - do not have the best effect on the sound. When using them, noticeable humps and dips appear at low frequencies.
The systems - consisting of small speakers and powerful transistor amplifiers - play well pop music, modern club styles, classic rock - and very mediocre jazz and classics.
The lightest and most open sound is produced by acoustic systems of “infinite volume” - when the dynamic heads are built into the walls, and their rear volume is not limited by anything. Or speakers - which are large shields with speakers built into them. The sound of the shields is very similar to infinite volume acoustics and greatly outperforms “Box” acoustics.
Unfortunately, in real houses and apartments these types of decoration are used very rarely - which is a pity...
... When jointly designing housing and acoustics in it - a design such as a shield or an infinite volume, can be built into the room with virtually 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 housing, the correct calculation of the crossover frequencies and joining of the bands, and the accuracy of the filter elements.
This multipolar task is difficult to accomplish for large-scale production. The acoustics are modeled and adjusted once - this happens at the stage of manufacturing a prototype.
In contrast to the external finishing - on the internals of the company, manufacturers usually - save...
Filter coils are wound with thin wire - which introduces increased resistance
To reduce copper costs while maintaining the inductance of the coils, iron cores are inserted into them, which have a bad effect on the impulse characteristics of the speakers
Copper and especially silver, used in coils and filter capacitors, are mixed in strange proportions with iron to save money.
Resistors for filters are inexpensive, usually metal-ceramic - low precision
Each dynamic head, produced in large-scale production, is at least slightly different from each other in terms of characteristics and sound.
Nobody makes individual settings for speakers.
The sound of commercial acoustics, even expensive ones, can be noticeably improved by adjusting the filters - changing the elements in them to more accurate and high-quality ones. Replace standard internal wiring with audiophile cables. Install additional spacers inside the housings to increase the rigidity of the walls, add vibration-damping material...
There is room to expand in the post-Soviet space, with its incredible reserves of ultra-pure copper and silver. This is something that domestic enthusiasts use very successfully to improve their branded speakers. This is a kind of “custom” or handmade production of unique copies not of Harley Davidson motorcycles, but of sound.
(By the way - many internationally respected foreign manufacturers of audio wires often purchase materials from the Urals or the Far East of Russia, where copper smelters still adhere to Soviet standards of purity and quality).
Fostex was founded in 1973. It is a subsidiary of FosterElectricCo., Ltd., one of the world leaders in the development of equipment for acoustic systems, as well as devices for converting and transmitting sound. The company has offices in 9 countries and employs more than 20 thousand people. Shares of Foster Electric Co., Ltd. listed on the Tokyo Stock Exchange.
Fostex was originally created to sell speaker components to consumers and dealers in Japan (in this country, a large number of ordinary people design and create home speaker systems of their own design; even today, the sale of components accounts 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 a wide dynamic range, which immediately won consumer approval and world fame.
The speakers of this company are widely popular among electro-acoustic speakers 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 manufactured more than a dozen speaker systems and, accordingly, had enormous experience in selecting speakers.
During the production of one of my projects - a two-way speaker on a Visaton W200 and Vifa XT25TG in the design of a quarter-wave voyage pipe (TQWP), my friends were offered a pair of FostexFE206En at a very tempting price. Unable to resist the long-standing temptation to listen to horn acoustics, and even on the Fostex themselves, it was decided to change priorities.
Thiel-Smol's parameters measurements showed 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 with very logical and rational solutions for absolute sound quality on the other hand - a massive magnet (more in diameter than that of a 12" woofer 150GDN from Cliver 75AS), a soft textile suspension and a flexible centering a washer, a lightweight diffuser made from banana tree fibers, as well as the presence of an even lighter composite film on the dust cap (used as a material for dome tweeters) for better reproduction of high frequencies allowed us to achieve a sensitivity of 96 dB / 1 W / m, with the prospect of using it in horn design and an excellent option for a tube amplifier.
The concept of a single-way speaker is very tempting due to the presence of certain advantages over multi-way analogues.
Among the advantages, one should highlight the absence of phase mismatch and time delays that occur due to correction filters, different distances between speakers, as well as different acceleration factors (the mass of the moving system, for example, in two-way speakers, when you need to connect a heavy woofer with a light tweeter, a threshold arises at crossover frequency), which brings its own unwanted distortions. Therefore, the sound of these acoustics is characterized by a special solidity and richness.
Another clear advantage of wideband systems is the careful selection of materials for the moving speaker system for maximum broadband, which makes it possible to use them in exotic and most reliable designs, in particular a reverse horn
(quarter wave voight tube) TQWP
ONKEN
According to the theory of horn design of loudspeakers, in order to achieve maximum depth in the lower register (at the sacrifice of greater efficiency), it is necessary to strive for the maximum length of the horn, and the largest possible mouth area at the output, while not forgetting to observe the golden proportion of 1/3 (neck/mouth) . According to various sources of information, the pre-horn camera should be equivalent to the volume of a closed box or bass reflex. In our case, this is 20 liters for a bass reflex 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, with the possibility of increasing up to 17 liters using a partition. The modernized drawing looked like this:
After assembling the case and the first test listening, there was an acute lack of depth in the lower register. The reason for this was insufficient sealing of the partitions of the horn labyrinth and the walls of the housing. By eliminating air leaks with sealant and pasting the removable side wall with sealant, we were able to achieve a much better result.
When measuring the frequency response and impedance of the speaker
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 the depth and articulation of the bass.
Fostex speakers have a very light sound that perfectly conveys instrumental music and vocals. The paper cone and horn design gives a neutral sound, with a slight splash in the upper mids and lower treble register. Therefore, it is necessary to preserve the original sound timbre of the speakers as closely as possible and make a small dip in the upper middle area. Since all types of coupling capacitors have a unique timbre, this should be taken into account when choosing the type of pass capacitor for a notch filter.
The following capacitors participated in the test:
-Metal paper MBGO: almost neutral timbre with slight presence in the lower mids, and a lack of high frequencies.
-Metal paper MBGCH, with an extended upper range of high frequencies: Too raw sound with a muted midrange and excessive high frequencies.
- MBM metal paper capacitors: rather ringing sound due to harmonics in the upper middle, distortion of the localization of sound images when constructing a scene of audio compositions.
- metal film K-73-17: neutral sound, excessive suppression of the upper mids.
-metal film K-73-11: neutral sound, excessive suppression of the lower high-frequency register.
The choice was made on metal film K-73-11, as the most suitable for the timbre characteristics of our speaker.
Installation of wiring to the acoustic terminal should be done as symmetrically as possible in the center of the horn, attaching it to the wall and setting the maximum tension.
The wait for the audition turned out to be justified and in the first seconds it left many unforgettable impressions. It was not possible to limit ourselves to a minimum test set of compositions to establish an assessment of listening to these acoustics. On the contrary, an insatiable desire appeared to listen to audio compositions of various genres, which was actually done.
Among the best qualities, it is worth highlighting a much wider focus, and the best elaboration and greater reliability of the lower register of all existing speaker designs.
The most reliable and high-quality reproduction of instrumental audio compositions is classical, light rock, jazz. Also, a well-articulated and powerful lower register plays pop, rap, etc. up to dubstep. However, this acoustics reproduces hard rock with some drawbacks.
After constructing this acoustics, the weak link of the remaining sound path began to be felt - the AsusXonar DX sound card. The discrete transistor amplifier HarmanKardon PM 655 still copes with the task, but these highly sensitive speakers with lightweight speakers will further reveal their potential in a duet 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 bass reflex and even Voight’s Quarter-Wave Tube due to the obvious loss in the reliability of the reproduction of audio compositions.
Therefore, when possible, I recommend using a horn design as a design for multi-band speakers and subwoofer systems.
I wish everyone good luck in designing horn speakers and the possible repetition of my project!
5.0 system for listening with a subwoofer.
I would like to present to your attention a recently manufactured 5.0 system based on speakers 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 speaker.
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 still a mandatory attribute of any “shell.” The situation changed with the advent of the first sound cards, which could provide 2-channel audio output. Now this system is called “scientifically” 2.0 (the first number is the number of speakers, the second is the number of subwoofers), but earlier they said it more simply - a stereo system.
The first multi-channel speaker systems were designated 4.0, which, accordingly, included 4 speakers - two front and two rear. Such acoustics give good effects in games, creating three-dimensional sound. Using the 4.0 system, you can, of course, listen to music, but the sound will not be much different from what you can get on regular two speakers. In 4.1 acoustics, as the name suggests, a subwoofer is added. True, these systems still remain four-channel - low-frequency signals are isolated in them using a special crossover.
The next type of speaker system already has 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 to acoustic 4.1, a central radiator has appeared. And it is needed to comply with the Dolby Digital format, often used in films, especially on DVDs. The central column conveys the dialogues of the characters. 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.
The agony of choice...
2.0 and 2.1. Most computer users are not very demanding when it comes to computer sound. If you listen to mp3 recordings and sometimes play, then 2.0 or 2.1 acoustics will be quite enough for you. Moreover, if you want to achieve high-quality sound, then simply buy a more expensive system. There is no point in purchasing more “advanced” acoustics, since they require a multi-channel sound card. And such costs for listening to mp3 (a format that does not have any special sound quality) seem irrational to me.
4.0 and 4.1. This acoustics is intended primarily for gamers, and especially for fans of 3D shooters. Especially for systems 4.0 and 4.1, game developers create impressive sound effects that can significantly lift the mood of 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 purchasing good 2.0 or 2.1 acoustics, you can listen to higher quality music than after purchasing 4.0 or 4.1 acoustics from the lower price range.
5.1. As I already 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 for you is clear. In addition, 5.1 acoustics give very good results when listening to music. In games, everything depends on whether the developers bothered to provide support for 6-channel sound. If not, then the use of 5.1 and 4.1 acoustics will differ little.
This speaker system was developed taking into account the following requirements:
1) The width and height of the cabinet were determined by the scope of installation of the speakers in decorative niches. Therefore, it was possible to compensate for the insufficient size of the speakers, for example in height, by using depth dimensions.
2) Sharing and coupling with an active subwoofer on a 12" head with an upper cutoff frequency of no more than 110 Hz from Mission M6AS
3) A rather modest budget to invest in.
This led to some difficulties, since the development of acoustic systems usually begins with selecting the volume and shape of the speakers to match the parameters of a specific speaker. In addition, the speakers produced in the USSR, with their lightness and richness of sound, had excessive quality factor, which is why it turned out to be impossible to listen to them even in a “closed box” design - a large uneven frequency response and, as a result, a heavy and mushy sound. For reference: the design of an open box can be done in the following options:
1) Absence of a back wall in the speaker system.
2) Using instead a sound-absorbing material stretched over the entire area; I experimentally select the thickness and material.
3) Use a perforated back wall, such as here:
However, the price for a “smooth frequency response” is a sharper decline much further from the main resonance frequency in the low-frequency region. due to an “acoustic short circuit” between the front and rear of the speaker cone.
A way out of this situation was found in the use of a second low-frequency speaker in the front and most important speakers. This made it possible to reduce the lower limit playback frequency to 90Hz and improve the radiation pattern of the acoustic system.
You can compare the frequency response graphs - the top box is open, the bottom box 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 settled on domestic ones, made in the USSR. They are highly valued in the circles of audiophiles, lovers of tube and vintage sound. Among the advantages you can consider:
affordable price;
High sensitivity (undemanding to the power of the amplifier and ideal for a tube amplifier);
Big potential.
I will dwell on the latter in more detail. Wideband speakers of domestic production had a very pleasant timbre, simply chic and enviable microdynamics and detail in sound for many foreign analogues, 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 diffuser. Of course, there were some casualties. Now we can highlight the main disadvantages:
Too uneven frequency response due to excessive quality factor and lack of mastic, which is used by imported dynamic head manufacturers to eliminate the above-mentioned shortcomings;
The appearance of most of the speakers, especially the basket, is rather unprepossessing, which is why you have to resort to non-standard solutions such as placing the speaker from the inside of the case or using grill grilles and decorative rings to hide these shortcomings. The choice settled on 8" 8gdsh-1 for the bass/midrange of the front and rear speakers
and 6" 5gdsh-4 for the central channel.
The legendary oval diffuser type 3gdv-1 was used as a high-frequency link, which gives a velvety timbre to the sound of the speakers, unlike dome tweeters.
However, the game is worth the trouble. The inherent potential can be revealed thanks to long and painstaking work on calculating and setting up the separation 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 angles of inclination. However, there is a problem: they must be attached to the back wall of the speaker, which we don’t have... Here we had to sacrifice the appearance of the top wall of the speaker, securing 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 by milling in the city was not successful, so I had to mill it manually using a template. However, after the work was done, irregularities and chips from the decorative film were revealed. The protective grill grille not only did not give the best appearance, but also worsened the appearance of the joints of the grille with the chipboard body.
To objectively evaluate the sound, the opinion of audio critics is necessary. A panel of critics consisting of relatives and friends was immediately created. Most of them are simply indifferent to music. And only 2 of them are musicians.
The test compositions were the Nigtwish Dark Parsons Play concert from 2008, recorded in DTS-HD Master audio 5.1 and 2.0 format. 24Bit 48KHz with audio bitrate 5400 kbps and concertMetallica: Orgullo pasion y Gloria - Tres Noches en Mexico 2009 with audio track formatDTS-HD Master audio 5.1 and 2.0. 24Bit 96KHz with audio bitrate 7200 kbit/second.
When we first listened to the 5.0 system, we noticed a clear localization of objects, a large-scale stage with an evenly distributed sound field, excellent microdynamics, the playing of each instrument was clearly audible, and most importantly, the reproduced sound images are not tied to the acoustic system, but are evenly distributed in the recreated powerful scene. Even when listening to these concert soundtracks and other single tracks in Flac format(uncompressed audio codec, quality is not inferior to 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 provided such a vast scene that even in a non-ideal room from an acoustics point of view, 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 configuration of the speakers.
Loading...