ReMusic interviews Mirko Marogna from Esoteric Pro Audio


To the first part of this interview


We are still with Mirko Marogna, designer and owner of Esoteric Pro Audio, what I affectionately call "the prophet of the DSP" because, in my personal opinion and after hearing confirmations, Mirko has already managed to obtain today what this technology has been promising us for a long time: the almost absolute control of the sound parameters with the ability to restore the natural dynamics of the sounds. For a quick entry on the subject, read here.


Question: When and how did you realize that using DSP could be an interesting way?

Marogna: I went into a master studio monitor project; the project was four-way and amplified with fairly cheap commercial amplifiers and DSP. Those monitors, despite the timbre and harmonic limit, had a phase coherence enviable even by very expensive systems. I remember listening to music recorded in holophony in the company of audiophile friends who questioned the fact that I played different versions from those they were used to listening to, while the result was due to the perfect acoustic phase obtainable, in my opinion, exclusively through the digital management of the crossover filters. From there the beginning of my journey that leads to the present day, where everything is managed digitally up to the amplification.


Vista interna di un audio manager DSP Esoteric Pro Audio Fibonacci


Internal view of an Esoteric Pro Audio Fibonacci DSP audio manager


Question: The DSP of your devices allows you a switching precision of 0.1 dB. However, it goes without saying that its adjustment and fine-tuning requires a qualified intervention. Would you like to tell us how broad the "field of intervention" of your approach through the DSP is and what it includes?

Marogna: I have developed my DSPs like perhaps no one else, as they contain the maximum expression of what technology allows up to now, both in terms of hardware, software and firmware. To specify some data, it is a processor that mounts an atomic precision clock of 10 PPB - Parts Per Billion, and Hi-Fi grade converters with a maximum resolution of 32 bit and 768 kHz. Processes work in floating point and much more. Despite this, the DSP is one of those machines where the intervention of the technician is more important than the machine itself.

The setup method must necessarily be supported by acoustic measurements and even just positioning the microphone correctly to perform them could cause problems, so I let you imagine the complexity. Obviously, this applies to those who are not satisfied and want to get the most out of a system. As far as interventions are concerned, I had a staff of engineers from a Venetian company that develops for third parties develop a setup software on my requests, requests that I matured working on various standard software and noticing, in some, serious limitations. However, the parameters remain the traditional ones: time domain, parametric equalizers, acoustic phase control.


Question: Speaking of DSP, there are FIR filters and IIR filters, for which readers can find a quick analysis by differences here - Ita only: which ones did you adopt and why?

Marogna: I only use IIR filters. This doesn't mean they are better; everyone has their own method of approaching things, in my case I found them more suited to mine. I briefly explain the reasons, the IIR filters have the problem that they generate phase rotations while the FIRs don't, put it this way the seconds should be preferred but I often find there is the need to generate rotations in order to align perfectly and I, with many years of experience, I learned to manage the phase rotations induced by the filters in my favour. Even in this case I chose the most complicated route, I just can't take shortcuts...


Question: Phase, frequency, volume, time domain: what are the acoustic parameters on which it is possible to intervene at the DSP level and which makes it so strategic in a modern approach to audio reproduction?

Marogna: Here we get into the specifics and it is not possible to give a simple answer. In reality, what I think is the real secret is being able to align the phase on the slopes of the filters and this was precisely the topic Be' and I discussed during the dinner that I mentioned at the beginning of the interview. To make this intervention possible, all the functions of the DSP are expertly managed. We also discussed the same thing during a breakfast in London with a famous professional equipment manufacturer, a certain Andrew Sterling, one of the founders of Allen & Heath, the company that built the mixers for Pink Floyd and he too was very impressed by my theory.


Question: Building on your experiences with the more exotic and established tubes, how did you arrive at class D? What did you see there, what convinced you? How did you develop it?

Marogna: I started using class D in the professional sector as it has become the standard for years now. The thing that immediately struck me is the dynamics and ease of emission, parameters that I found lacking in Hi-End systems, as mentioned before. Certainly, the class D amplifiers dedicated to the pro showed substantial gaps in terms of timbre coherence and reproduction of harmonics. On closer inspection, however, it was undeniable that pro amplifiers paid no attention to the selection of components or to the care of power supplies, always very close to being able to keep costs down. My bet was to try to develop class D trying to pay the utmost attention from every point of view, as was the custom for noble Hi-End devices, even trying to go further. So not only boards with golden tracks or careful selection of each component, but also frames that guarantee vibration control and wiring with very high purity materials.


Vista interna di un finale stereo Esoteric Pro Audio Caravaggio


Inside view of an Esoteric Pro Audio Caravaggio stereo power amp


Question: Indeed, there are relatively few manufacturers of quality class D modules, for example Hypex, IcePower, Pascal, Powersoft, Purifi come to mind. Their offer seems to be enough for the market. Instead, what prompted you to want, imagine and have proprietary class D modules designed and built? In my opinion, there is something to be proud of with the result, so what do you think are the main differences compared to your competitors on the market, those who justified your entrepreneurial effort?

Marogna: I state that from an entrepreneurial point of view it was madness, any analyst who had tried to draw up a business plan would probably have locked me up... But, returning to the subject, I reiterate the concept I expressed at the beginning, adding others. The modules found on the market are all or almost all made with industrial methods, if the designer foresees a capacitor on the circuit of a certain value, the buyer of the company issues a purchase order for capacitors that fall within the parameters without the slightest idea of how they behave acoustically on that circuit. And so are all the other components. In my case, I wanted to personally decide the choice of each individual component by testing, through prolonged listening, various brands, related models and any other possible variable so as to obtain the timbre that was closest to the neutral, colourless, but at the same time rich in harmonics. Unfortunately, this type of selection cannot be done instrumentally, and it is not even decisive to mount the simply "more expensive" components, because often they are not the ones that give the desired results. Worse yet, when you choose a particular component in one location in the circuit, it doesn't necessarily turn out to be the best choice in another location. All this work has required months of improvement, something that industrial companies do not do, both for the cost that determines it but above all because it is difficult to find technicians prepared for long listening sessions for such a selection.


Dettaglio di una scheda di alimentazione Esoteric Pro Audio


Close-up of an Esoteric Pro Audio power board


Question: Your equipment, Fibonacci and Caravaggio, can also be used in other, more "traditional" systems, pass me the approximation. This is perfectly understandable with Caravaggio power amps: mono or stereo, they can be placed downstream of any preamp and give the performance of dynamics, power and refinement that your exclusive hybrid class D modules, with linear driver and switching power amp, are able to offer. Are there any other benefits?

Marogna: More than other advantages I would call them consequences. Many enthusiasts believe that the loudspeaker is the main access door to good sound, I personally believe that these beliefs derive from the fact that amplifiers are very rarely able to adequately drive the loudspeakers. I’d like to say that in the majority of loudspeaker pairings- amplifiers actually "drive" the speakers, which is why people believe they are the most important component. In the case of the Caravaggios the situation is reversed, on each loudspeaker I have connected them they show their character in an overbearing way and therefore "command" them on the loudspeakers by clearly noting my sound signature, a characteristic which is based on the absence of added colors and silence absolute, thus leaving room for the micro information and the original timbres of the recording which I believe are the real key to the beautiful sound.


Question: In the case of Fibonacci, on the other hand, we are not dealing with a "simple" pre: it would be reductive and imprecise to define it in this way. Being a DSP audio manager, the Fibonacci allows not only to drive power amplifiers but also to bring to them, like and better than an active crossover, the exact portion of signal suitable for the single way of the loudspeaker. Furthermore, with Fibonacci you can intervene and correct the signal exactly for the sweet spot, for the listening point, linearizing it as desired or enriching it to the taste of the listener. In short, your DSP can drive any power amp at full range, with any environmental and frequency corrections, but also act as a real crossover "upstream" of any other power amp model, bypassing the passive crossover of any model at the start of production diffuser. Am I right? Is there more?

Marogna: True, the Fibonacci is not a simple device to explain as these devices are not commonly used in the Hi-End world. In simple words it has the function of converter, and in reality, it has three on board, but also of pre, crossover and, dulcis in fundo, environmental calibration, the latter characteristic not to be underestimated as it allows any loudspeaker to be adapted to any environment. On the professional market there are dozens of brands that produce devices with the same functions but, as far as I know, Fibonacci is currently the first audio manager to have been implemented for Hi-End use. Therefore, if we were to insert it in a traditional system, it could take the place of any DAC, with the advantage of being able to align the environment as well. Or those who have multi-amplifiable loudspeakers could put an amp for each way and correct it individually, correct them all one by one, an operation which, I guarantee, improves any loudspeaker in a very consistent way. In summary, the Fibonacci becomes the heart of any system in which it is inserted.


Question: I have to and want to try everything, it's my job, but, if I can give a one-off argument in favor of my personal taste, my liking goes immediately to high/very high efficiency systems. What do you think about it? In short, why in 2023, almost 100 years after the compression driver patent, can we still not do without horns, if correctly designed and implemented?

Marogna: I believe that all high-efficiency instruments, including compression drivers and horns as well as class D amplifiers, make it clear how capable they are of reproducing sounds with ease of emission, something that low efficiency does not it is still able to replicate, and this goes in the direction I was talking about earlier, i.e. returning the transients closer to those of the live instruments.


Vista parziale dell'impianto personale e di riferimento di Mirko


Horns, horns and horns, still today, more than one hundred years old and passing from their first audio uses... Partial view of Mirko's personal and reference system: just to give an idea of the dimensions, the loudspeaker is tall about three meters.


Question: Your systems combine in a unique way, never heard before, the ability to express the details of musical pianissimo with the ability to play loud and without distortion. As I've told you on other occasions, I've never heard of a system capable of doing the same until your systems. As long as it's a question of playing a couple of instruments at a level of volume everyone is capable of, just take a walk around a shop or a Hi-Fi fair, but reproduce volume and dynamics together, two different sound components, well, here the game gets tough. How did you do it? And how do you explain this enormous removal of the market, which we all have before our eyes and which nobody talks about? In short, when did the "realism" of reproduction, made up of power and dynamics but also of nuances and details, abandon us?

Marogna: I often joke to my clients that the problem is not moving the drivers but stopping them. If the loudspeakers are not properly driven, the inertia spoils the subsequent sounds creating confusion and distortion, the problem at low volume remains acceptable but if you raise the level or listen to complex music it shows all its limits, a reason that convinced me to think that driving power is never too much. Then, as an old commercial said, power is nothing without control.


Question: Even just a quick and superficial listening to your systems, the professional one, the one intended for the Hi-End segment and your personal one, made me understand how far a "traditional" system is from the possibilities of a correct and real phasing, both electric, and it seems to me the least, as much as acoustic, and here many systems, even large and very large, cannot win against yours. How did you achieve these results of correctness in listening? What are the main aspects you faced and how did you solve them?

Marogna: you already said it, the acoustic phasing of any system is, in my view, the most important parameter for any system and is obtained through a setup perfected through the experience of the person who runs it. This is why all my systems have their own extremely common and recognizable character, let's say a sort of signature. Everything comes from a thought, I like to call it a philosophy, which is concretely a method. Everyone has their own, especially when working in digital, there are so many variables that it is impossible for two technicians to obtain the same sound even on the same machines, and if you allow me I find this thing extraordinary, one feels a bit like an artist.


Mirko Marogna e Giuseppe Castelli


Mirko and me relaxing in his theatre


Question: The final curiosity, do you have any tricks or fine tuning of the system that you can suggest and would like to share?

Marogna: Rather than giving trivial advice, I am convinced that to achieve results you need to change your point of view: if you always follow the same path the finish line will never change, then I believe it is essential to have clear references, which cannot never be your own system. I made a big leap in quality when I stopped looking for what I like and trying instead to understand what is right and what is wrong. I think these here are the right prerogatives to start the journey. In addition: never forget that tests are always relative, never absolute. Objects tested in one setup with poor results could turn out to be excellent in another setup. So never take your experiences for granted. Therefore, every time a device is changed, all the previous tests should be redone, for this reason I would not feel honest in recommending certain operations. Another advice is to always move towards non-coloured and neutral sounds, even if with this prerogative everything gets complicated because you need to be able to reproduce what are the "colours" of the recording and perhaps this is the most difficult thing.


Ends | To previous part


For further info:

to Esoteric Pro Audio website

EPA Fibonacci Audio Manager manual

EPA Caravaggio Hybrid Amplifier manual

EPA Kora Speaker System manual

Esoteric Pro Audio Fibonacci audio manager
Esoteric Pro Audio Fibonacci audio manager
Esoteric Pro Audio Fibonacci audio manager
Esoteric Pro Audio Fibonacci audio manager
Esoteric Pro Audio Caravaggio power amp
Esoteric Pro Audio Caravaggio power amp
Esoteric Pro Audio Caravaggio Mono power amp
Esoteric Pro Audio Caravaggio Mono power amp
Esoteric Pro Audio Caravaggio Stereo power amp
Esoteric Pro Audio Caravaggio Stereo power amp
Esoteric Pro Audio Kora loudspeaker
Esoteric Pro Audio Kora loudspeaker
Esoteric Pro Audio Kora loudspeaker
Esoteric Pro Audio Kora loudspeaker
Esoteric Pro Audio Kora loudspeaker
Esoteric Pro Audio Kora loudspeaker
Esoteric Pro Audio Kora loudspeaker, mid-high ways close-up
Esoteric Pro Audio Kora loudspeaker, mid-high ways close-up
Esoteric Pro Audio Kora loudspeaker, mid-high ways rear view close-up
Esoteric Pro Audio Kora loudspeaker, mid-high ways rear view close-up
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