A Mad Dog Can Travel Seven Miles a Detour, or How to Make a Great Horn in the Maximum Time

You've probably heard the old saying that a mad dog doesn't care about the distance. It means that if the goal is really important, then it's worth taking a long, winding path to achieve it. The same thing happens when we try to create something truly worthwhile under conditions of acute time pressure.

This article is not about how to do something “normal” quickly. It is about how to create a powerful tool — your own “megaphone” that will sound loud and convincing — in a short, almost impossible time frame. We will talk about focus, priorities, and a few non-obvious techniques that will help turn a rush job into an excellent result.

Let's figure out where to direct all your energy when the clock is ticking and there is no turning back. Sometimes the most straightforward and bold decisions turn out to be the right ones.

Introduction. How I came to write this article

Everyone knows that Russia is not the most welcoming country for compatriots who are doing something new (or doing anything at all, for that matter). We follow foreign trends with much greater interest and view innovations from our fellow countrymen with greater skepticism, believing that everything “they” have is cool, while everything “we” have is, at best, questionable. As a result, even a good product is extremely difficult to bring to the consumer if you are not an oligarch and cannot blindly throw millions of evergreen dollars at advertising.

I should mention that there are, of course, some pleasant exceptions: several audio magazines agreed to listen to our setup and write about their impressions—many thanks to them for that. Some refused to do it for free, and commissioned articles are not our way. We agreed with the editors of stereo.ru to arrange a listening session in 2020 on the condition that I would write a saga on the topic of “how it was” beforehand. Actually, why not — such examples help to turn desires into reality more quickly and motivate us to achieve great things. I will say right away that this describes about 1% of all the experiments and difficulties that the project had to face and overcome. Many topics remain undisclosed. If readers have any questions, please write them in the comments, and I will try to answer each one.

Introduction

So, let's get acquainted. I am Konstantin Rumyantsev, an engineer and the initiator of the Operly project, which is already well known in audiophile circles. My school hobbies were electronics and music. Accordingly, I have two degrees in the subject that interests us: the first is in physics (department of radio electronics), and the second is in classical guitar teaching. I received them in that order. Both degrees are full-time, what is called “from bell to bell.”

Besides, I was involved in rock and roll for about 10 years. Actually, after school, I wanted to go to a technical university to design low-frequency amplifiers, but I couldn't find a program like that, so the closest thing was the radio electronics department. I graduated in 1994. Probably, if the country hadn't been going through such turmoil at that time, I would have immediately started designing audio equipment, but then such things were happening… There was no time for electronics. In general, when things calmed down, I wanted to try to realize my long-standing dream.

Another motivation for me was my daughter, Sofia, who was growing up. She was 13 when the project started. Children are like sponges. They absorb everything around them, and it's useless to explain anything to them; it just has to be part of their lives. Sofia grew up to be a smart, tech-savvy, modern girl. I managed to instill in her the right taste in music: Deep Purple, AC/DC, Black Sabbath, and the Rolling Stones are her favorite bands. I wanted her to be involved in the process of design and invention as well.

I know from experience that until you try everything yourself, even the smartest books won't give you even a rough idea of what real R&D is like. Of course, I did most of the work, but Sofya helped me too — I gave her tasks: translate something into Russian, change the speakers, etc. I also always consulted with her and shared my thoughts, and we discussed new ideas. It was nice to see her growing independence, and I was able to entrust her with more and more. As a result, she began to show initiative, get more involved in the process, and look at the project from an entrepreneurial perspective, which I couldn't help but be happy about.

MARK 1: the speaker on the back of the deck is better than the one on the front

Somehow, I ended up naming my models' technical names after Tony Stark's Iron Man suits (my daughter and I joke about this). Accordingly, the first model is Mark 1. And this is not a horn, and here's why: my thoughts did not immediately lead me to this type of acoustic design. At first, like the vast majority, I thought in terms of ZYA (a closed box) and/or FI (also a box, but with an opening and a tube inside).

So, the first model, also known as MARK 1, was a classic ZYA. It featured a rather clever jamming system inside the body, the principle of which I borrowed from microwave technology. At that stage, I didn't want to bother with a multi-band system, so I settled on a broadband speaker.

MARK 1 went through a few iterations, which gave me a lot of useful experience:

• Installed the SP in the case — well, the sound is just sound, the bass isn't thick, nothing special.

• I reinforced the enclosure (especially the front panel) — the sound became more accurate, reinforced it further — even more accurate. The latest iteration — a steel stiffener on the front deck. In this configuration, the accuracy of the images and articulation were already quite decent and outperformed conventional mid-range multi-band speakers in these categories. The owner of the entry-level Focal ($3,000) came to me one day and said that I had surprised him greatly.

• Probably the most important experience, which had the biggest impact on my further development and which I didn't realize right away. In the heat of experimentation, I replaced the speaker with a higher quality one, but its basket was slightly larger. I was too lazy to increase the mounting space by a few millimeters, so, thinking I was being clever, I attached the speaker to the inside of the enclosure and simply cut the front edge at an angle with a knife. With this speaker, the sound was head and shoulders above the rest, but I was definitely not happy with the clumsy appearance of this solution. In the end, the mounting hole was cut to the size of the basket, everything was done neatly, and the speaker was screwed onto the front of the case. And you know what? I didn't like it!!!

Something elusive had changed, somehow there was less magic. No, no, the measurements were the same, but I didn't spend four years in school playing guitar from morning till night to be wrong about such things. But at that time, like most of my colleagues, my understanding of sound revolved around frequency response, phase response, TDH, etc. — in short, it was insufficient to draw the right conclusions. I didn't understand what had happened at the time, but that moment stuck in my memory.

Now I understand that by securing the speaker from the back and making an expanding profile with a knife, I ended up with a primitive horn. The thought didn't occur to me at the time, but it stuck in my mind. My efforts at that moment were limited to searching for an acoustic design that would allow me to raise the bass, which was clearly lacking.

MARK 1, speaker loaded from the rear of the front panel

After tinkering with the ZYA and converting it to FI, I realized that the best I could hope for with this design was to achieve the same results that other “smart guys” had already achieved, which meant joining a long queue to win over consumers. I didn't want to be number 100,000 in line, so I decided to continue my search.

By the way, there was another extremely useful experience: when I made changes to the design, I first assembled one speaker, then turned it on, and if the experiment was successful, I assembled the second one, and the first one played while I fiddled with the second one. So, every time a pair was turned on, it wasn't very good, but after a while, everything adjusted. This was noted by Sofia, her friends, and my friends, i.e., people who were not prepared. The conclusions are as follows: the slightest difference in the speakers ruins the stereo image, so it is extremely important to make the enclosures as identical as possible, and the speakers must be warmed up before testing.

MARK 2: after cutting a hole in the baffle, I realized that the sound was no longer “clamped.”

While working on the previous model, I read a lot of literature on acoustic design, and my attention was drawn to a design called “Voight's tube,” also known as TQWP. Like most novice audio designers, I saw the ideal in a perfect frequency response — like, “just level the frequency and you'll be happy.” TQWP was a good candidate, as it promised a relatively simple design and excellent (according to measurements) results.

MARK 1: speaker on the front of the panel, steel stiffener

So I ordered the cuts, assembled everything “by the book.” I experimented with damping material. It seemed like there was more bass, and the speakers were the same, but the sound was impossibly flat. Anyone with a college/conservatory level music education knows that finding “your” sound is one of the most important parts of learning. The sound should be round, strong, and flying.

Sound is an integral part of a musician and a piece of music. When you work on sound for years, you develop a different attitude to what comes out of the speakers, and you get more annoyed when the sound is poor. The sound in MARK II was extremely poor, even though its frequency response was much smoother than that of MARK I. Paradoxically, however…

Mark 2, Voight's Trumpet (TQWP) — still stands today at a friend's place

I don't even understand how I came to the next step — let's just say it was intuition. The thing is, the TQWP has a partition behind the speaker: I freaked out, took a 50 mm cutter and cut a hole in the partition right along the speaker axis. Lo and behold, the “flatness” disappeared. Now these speakers could be listened to quite normally, without irritation. By the way, the bass frequencies did not change.

The conclusion from this experiment is that there should be as much free space as possible behind the speaker. Any compression of air distorts the sound.

MARK 3: another bad idea

Since TQWP was, in a sense, a reverse horn, why not make a real reverse horn? As you might guess, I'm good at math — I calculated the cross-sections of an exponential horn with a pre-horn chamber. Since at that time I didn't have any production space — just a rented 12 square meter room — the question of how to make such a complex structure was very acute. I ordered the cutting of the body, but decided to make the reverse horn itself out of foam. It's obvious: it's easy to work with, cheap, easy to shape, and it won't be too hard to cut an expanding profile in it and get the result I want..

MARK 3, foam horn — a silly idea

No sooner said than done. It turned out to be a complete disaster. Mark 3 was even better than the previous model, but the bass was sluggish, lifeless, dull, and boomy, even though the volume itself was excellent. The idea of making a horn out of foam turned out to be outrageously stupid, because foam is solid to the eye, but quite loose for sound — and the lower the frequency, the deeper the wave penetrates the material, and only God knows what happens there.

MARK 3 in assembled form

It's safe to say that any formula for calculating a horn assumes that the walls are completely rigid. The further the horn walls are from being completely rigid, the further the sound of the real horn is from the calculated one. Conversely, the more rigid the wall, the closer the result is to the ideal horn. I believe that most of the horn's detractors have had experience with horns that are not rigid enough or have resonating walls, and instead of a beautiful open sound, they have heard a confusing mix that many mistakenly consider to be “the horn sound that I don't like.” .

27. All About Eve (1950)

26. Limelight (1952) Joseph Leo Mankevitch tells the story of the road to fame: Eva is hired as an assistant to Broadway star Margot Channing and, step by step, develops a plan to replace the aging diva. The heroine is aided in this endeavor by theater critic Addison DeWitt, who will stop at nothing to see the plan through. A brilliant epitaph to vice in every sense of the word.

The idea was this: I cut out the negative of the reverse horn from foam, a kind of expanding sausage, use it as a mold, “roll” fiberglass onto it—this creates a positive matrix of the horn—and then fill the matrix with construction foam (this creates the same kind of “sausage”), take it out of the halves, glue it together, mount it in a wooden case, pour concrete over it, and then, when it hardens, simply tear the foam out of the concrete, obtaining the desired expansion profile. This, by the way, is a pretty cool idea for DIYers, which allows you to get any shape cheaply and easily, without any CNC machines.

MARK 4 with a straight horn made of foamed composite and painted with glitter (my daughter's idea), which looks rather controversial. The same 4a28 is installed here.

This model was supposed to have a straight horn made of vibrated concrete. However, the manufacturer we had a contract with dragged it out for six months and then returned the money, so we had to make the straight horn ourselves out of foamed composite. This material is much better than foam, but it is expensive and not rigid enough.

The negative of the straight horn for the Mark 4 is made of putty and covered with epoxy. See the nail in the center? The plywood profile of the horn was placed on it, and by rotating it, the required surface was obtained.

The MARK IV sounded pretty good. For some genres, it sounded excellent. No wonder: concrete is hard and non-resonant, unlike foam. To fit the model into kitchen dimensions, it was decided to make it with a 10-inch speaker, which reduced the length of the rear horn — one of the reasons for the large size of all rear horns.

The problem was that I couldn't find 10-inch speakers of sufficient quality that were mass-produced, had a high frequency response of at least 17–18 kHz, and were reasonably priced. Even after buying Audionirvana, I was still dissatisfied. I liked the 4a28 the most. But first, they were no longer being produced, and NOEMA, which is considered their successor, produces speakers for completely different purposes (I tried them too). Secondly, the high frequencies were still lacking, and thirdly, these speakers worked well in a very narrow volume range: if you turned them up a little louder, the diffuser began to distort. I didn't like the coaxial experiments either: measurements are measurements, but the sound was somehow incomplete. I still have several shelves in my basement cluttered with 10-inch speakers of various models.

In summary:

• concrete—although it is an acoustically suitable material and inexpensive, it is dirty to produce, takes a long time to gain strength, is inconvenient to work with due to its moisture content, and is very heavy. This technology raised questions during the production process.

• the model itself has a short horn and an undersized outlet, resulting in unevenness in the low frequencies.

• the main thing is that I didn't find a speaker that I liked enough. Looking back, I think I didn't push this model hard enough. Now I know guys who could make a 10-inch speaker with a normal top end. Maybe someday I'll return to this model or this technology as the cheapest possible way to make a horn.

Sometimes, to do something really well, you just need to take your time — even if the whole world is waiting for quick results. Just as seven miles is no distance for a mad dog, it is important for a true master to go the whole way, no matter how long it takes. An excellent horn cannot be carved in five minutes: it requires patience, trial and error, and time. The main thing is not speed, but attention to detail, understanding why it is needed, and the desire to make it so that it sounds clear and loud. Sometimes slowing down is the right thing to do.

MARK 5: conciseness, conciseness, and more conciseness

By the end of 2015, my understanding of the ideal speaker system was described by the following theses:

• full horn (direct and reverse).

• absolutely rigid enclosure;

• minimum joints — preferably none at all;

• 8-inch speaker. Larger sizes suffer in the high end, smaller sizes suffer in the low end. 8 inches is optimal;

• maximum base dimensions: width — 600 mm, depth — 800 mm. This is approximately the space occupied by a person sitting on a regular office chair with their legs tucked under them — that is, very compact;

barry Levinson in the director's chair, Dustin Hoffman and Tom Cruise in the lead roles. A landmark film of the 1980s, loved by critics and audiences alike, this is a story about what can be changed and what cannot be changed—and that it is enough to simply accept it. And, of course, one of the most powerful arcs of the main character—it is impossible to take your eyes off Cruise's transformation.

• repeatability of production.

25. Rain Man (1988)

Now it seems obvious that there was no other way to draw it. But considering that every 1–2 days I started drawing everything from scratch, and the first acceptable profile layout that didn't make me sick appeared a month and a half later, you can calculate for yourself how many attempts were made. And that was just the beginning.

A mosaic of Federico Fellini's memories – the charm of youth, the bright sun of the town of Rimini, the 1930s brought to life. Nostalgia as it is, raw emotions, experiences, and passions laid bare. The great Charles Chaplin sums up his work – in Limelight, he plays the elderly clown Calvero, who saves a dancing girl from suicide. Will this be the beginning of a great love, or will the age difference ruin everything? The range of emotions and feelings of the characters, their confrontation with circumstances, and their attempt to resist the norms are conveyed at the highest level in this film.

When I was still struggling with the sketch, I constantly stumbled upon the following question: how to mount the speaker in a full horn? Looking through thousands (really thousands!) of horn designs, I did not find an answer to this question. If it were just a reverse horn, everything would be clear: we make a reverse horn and load the speaker from the front. If it were just a straight horn, it would be the opposite: mount the speaker on the back of the horn and no problem.

With a full horn, there is an eternal dilemma: either the throat of the direct horn must be not the diameter of the speaker cone, as required by the calculations, but much wider so that the speaker basket fits into it. Or the straight horn must somehow be mounted on top of the speaker basket, in which case it must be removable for maintenance purposes, i.e., it must be able to be attached or screwed to the reverse horn in some way. I didn't like any of these solutions because they violated the basic rules:

• the throat of a straight horn must fit tightly against the speaker cone. Remember the experience with MARK 1, when the horn turned out to be small, literally 2 cm? The precision of the horn throat is the key to a clear sound image and divine horn sound, so the option with a straight horn, where the throat has a diameter that allows the speaker basket to be placed inside, is not suitable.

• there should be no joints, because each joint distorts the sound, and it is unclear how a threaded connection, on which a rather heavy straight horn is suspended, will behave over time under constant vibration — so screwing the horn onto the speaker basket is also not an option.

• the laconic appearance does not allow for the use of any flanges for normal bolts.

IDEA!!!

So, while I was still working on the sketch, I had the idea to break the geometry of the straight horn to the size of the speaker basket and attach the speaker directly to the reverse horn. This would connect the speaker to the substantial mass of the column, which is good, and the disrupted geometry could be restored with a compensating ring that fits over the speaker and restores the geometry of the straight horn (the red ring over the speaker is it). The idea of attaching not the entire horn to the basket, but only a ring that continues the geometry of the straight horn and fits snugly against the diffuser, seems obvious at first glance, but it solves all the problems:

• the straight horn and the reverse horn are now one piece — there is no need to make them separately and then assemble them.

• the straight horn fits snugly into the speaker's diffuser.

• there is no need for any flanges — now the straight horn “flows” into the reverse horn, everything is concise and technologically sound.

Then there was a long story about how I struggled with a 3D designer, who finally drew a 3D model, chose colors, and went through a long saga with manufacturing.

The very first, still only computer-generated, version in red and black, which was made for me by a designer friend. The first set was then produced in this color. This color scheme is still the main one today.

After the first listening session, it became clear that this version of the horns simply had to be commercially attractive — it combined all the key points:

• had excellent uncompressed sound. As one buyer said when we played Vinyl Jam 2017: “It's like opening a window” — this was after listening to much more expensive setups, and one woman even cried (really, really).

• it should have, I would say, an outstanding appearance.

• was technological and repetitive.

This model was ready to be shown to the general public and was named Intelligence, as if hinting that intelligent music would sound best. Intelligent music here refers to classical, jazz, choir, not-too-heavy rock, acoustic genres, etc.

As you can see, creating an effective mouthpiece for your cause is not a one-day task. It requires not so much haste as a thoughtful approach and constant attention to detail. It is important not just to shout louder than everyone else, but to find your own recognizable voice that will resonate with the right audience.

The main conclusion is simple: don't chase speed for speed's sake. It is much more important to build a solid foundation — whether it's quality content, trusting relationships with subscribers, or a well-thought-out strategy. Slow but steady growth often proves to be much more sustainable than a momentary surge of attention.

Remember the saying from the title: sometimes the long but straight path to the goal turns out to be the most reliable. Work consistently, experiment, listen to your audience — and over time, your “horn” will become that powerful tool that will work for you for many years to come.