Thoughts are born, ideas are thought through and know-how is taken by us to extremes. We have developed the most innovative technologies, increased efficiency and enhanced the level of performance. And yet, we did not embark upon this path to put knowledge, skills and pioneering spirit in the foreground, but to make this very special feeling even more tangible: the absolute enjoyment of listening to music. 


Alfred Rudolph

Music is a key element within our emotional quality of life. It becomes authentic and immediately tangible by playing musical instruments. In the world of music playback, on the other hand, music is being often “administered” by devices …

Administering does not go well with emotions, neither does constriction partner with experiences. However, devices are essential to have music of any kind available at any time and in any location. It is our responsibility to build the bridge between the musical and the technical worlds.

According to our ideal, devices become instruments. Outside and inside become one, as close as possible to the human being, to the senses, to the core of human existence. Optimum sound, broadest longevity and an exceptional functionality are the workpieces to shape this bridge.

All loudspeakers are lovingly handcrafted in our manufactory and serve as ambassadors to the goal of making music tangible to the human being. They arise from the sheer love for music, harmoniously composed to a synthesis of the arts, embodying a unique combination of design, function and technology.

Excerpt from a letter correspondence from 1992 by Alfred Rudolph


“The most beautiful and magnificent thing the human mind has ever created is music. It has accompanied all human cultures since the beginning and is at the same time its cosmic dimension.

Today it is clearer than ever to me that I have been dedicating my whole life to music, in all its facets and expressiveness. In this year, 1992, I turn 50 and almost exactly 30 years ago, I began to grapple with the technical aspects of music reproduction. My first speaker got created. This “orange crate” with holes in it, out of which sounds escaped, appeared to be such good sounding that I kept listening to music with them for over six years, while my friends visited me for this reason time and time again. Since they wanted such speakers as well, I gave in to their urge and got started.

On the path of architecture, I began exploring the world of “loudspeakers” in all its dimensions. One thing became clear to me very early: Music plays in time …. once that is achieved through a music playback system, you forget it completely while listening.

Playback devices have been requested for an outstanding behaviour in the time domain, also called “timing”, for quite a long time now – but loudspeakers remained somewhat common in their construction. A music signal that unites all time domains in itself seldomly played a role in loudspeaker design.

This is 1992, and a new era is dawning for me: music plays in time and loudspeakers play music.”


Yours sincerely,
Alfred Rudolph, 1992


45 years of fascination for loudspeakers


Our Acapella loudspeakers stand for the fulfilment of a musical dream unique in its kind.


Since being founded 45 years ago by Hermann Winters (1) and Alfred Rudolph (2), we are considered one of the world’s technology leaders among manufacturers of horn loudspeakers. We have set milestones in development with the ion tweeter (3) and the spherical horn (4). Both developments secure us unique selling points compared to our competitors. The ion tweeter is the first light-as-air system that excites the air via a massless plasma flame and generates sound without tonal discolouration. This makes it clearly superior to all other conventional designs. The spherical horn doesn’t colourate as well and impresses with a highly dynamic sound. With great success, our products have been presented the first time to both public and a worldwide audience at the IFA consumer electronics fair in Berlin.



The charm of the extraordinary


In the 1980’s we get started as “Acapella Audio Arts”. Many exceptional speakers that meet the highest requirements in terms of sound, technology and design, shape this phase of creativeness. In addition to the ion tweeter ION TW1S (“S” for spherical), the product range already includes the speaker models Fidelio, Triolon, Celestron, Celesta MK 2 and 5th Avenue (4). We busy ourselves intensively with time-coherent systems, resulting in outstanding creations such as the exceptional transducer Sarastro (7), which is still used today in renowned recording studios as a reference system.

Hermann Winters

Alfred Rudolph

The aesthetics of the particular


Out of this wealth of ideas, the models Violon (8) and Campanile (9) are created in the newly occupied production premises in Duisburg. The first-mentioned represents our best-selling system with over 1,000 sold units. The latter, the Campanile, is now being offered in its fifth generation and has accompanied many of our customers for almost 30 years. Both loudspeakers continue to set standards in terms of sound, technology and design. Their foundation is grounded on a timeless idea that has retained its youthful freshness. And that’s because our continuous further developments offer even customers of the first hour upgrades to the current status. So every new generation of Violon and Campanile is a new start for an even better version. Ownership periods of several decades are not uncommon among our customers. It is important to us that our loudspeakers represent dreams that are achievable and have a long-term validity.

Innovation with passion


Since the turn of the millennium, the resonance optimization of electronic and mechanical components has become our focus in the search for the best possible sound. Elaborate measuring methods (10 – nicht unbedingt->siehe Foto) prove the positive sonic effect on the playback quality. Among other things, bases (10) for speakers and electronics are the results of this work and lead to the awarding of numerous patents. Another result of our relentless thirst for research is the hyperspherical horn (11). The transmission range increases from the common three octaves of

“normal” horns to now over five octaves by at the same time providing a distortion-free spatial imaging. All technical parameters are optimized and lead to a much better sound in every respect. A new generation of loudspeakers is born.

An Acapella speaker is not an everyday speaker. But a speaker for every kind of music.

It is not only the passion for designing loudspeakers, the will to perform, the urge for precision, the pursuit of superlatives, but also the sense of aesthetics and the sense of functionality that characterize our loudspeaker creations. All our fields of knowledge now converge into one another better than ever: architecture, electrotechnical knowledge, resonance optimization, material expertise, knowledge concerning spherical and hyperspherical horns and ion tweeters. All of this following the dream of the best loudspeaker, to which we get a little bit closer with every idea day by day.

The Acapella principle


Wthin the current hyperspheric horn series we follow a plan, an ideal that unites us all at Acapella. The principle being to get the maximum out of the given possibilities. Because it’s very much about the intelligent way to convert electrical signals into speed and musicality. Out of the Violon arises the Cellini (12), out of the Violoncello the Cecilia (12), and out of the Campanile the Campanile 2 (12). Above these models ranges our top series with Atlas (13), Apollon (13) and Poseydon (13). All of them are more instrument than loudspeaker – and ambassadors of music. This statement sums up everything that matters to us. As a brand. As a company. As a speaker manufacturer.

Tradition is obligation


For more than four decades, we have been moving forward with a great sense for performance and passion – and with a lot of impetus. Always developing new models. Incoporating more and more innovation. And craving for more and more musicality. And that’s how our future will look like as well. Richard and Robert Rudolph (14) have joined the company management by bringing in their young and fresh know-how. They grew up in the tradition of Acapella Audio Arts. The enthusiastic guitarist Richard has been a valued member of the Acapella mothership for more than ten years. He follows in the developer footsteps of his father Alfred.


Together we work daily on new and exciting products for our worldwide customers. With masterly craftsmanship, quality materials and an aesthetics of lasting validity.


Horn technology


Our horn speakers have an instinct for excellence based on decades of innovation and thoughtful design, merging into our unique transducer systems intended to bring your music to life.



We have been the technology leader in designing and manufacturing horn speakers for almost 50 years. Moreover, we are the inventors of the spherical horn. In the audiophile world nothing comes to the heart of our speakers. The pinnacle of our knowledge is the new, patented hyperspherical horn, which allows listening at the highest sonic level and guarantees an exciting musical experience.


The spherical horn concept was created in 1978 in cooperation with the University of Aachen. Unlike conventional horns, our spherical horn radiates sound waves in a spherical shape. This corresponds to the ideal principle of the one-point-source. The shape of our horn combines the extreme dynamics and speed of a nearly massless diaphragm with the efficiency of a horn, without creating distortion or tonal discolouration. 


The pairing of our extraordinarily fast diaphragms, which produce signals only via slight excursions, with the horn itself and amplifying them through the funnel shape results in extremely fast impulses and sets new standards in authentic music reproduction. 


We value the highest quality and attention to detail. Our double-walled, glass fiber reinforced horns filled with resonance-damping materials represent the feasibility of loudspeaker design up to this day.



Day by day we tirelessly attempt to push the boundaries of what’s possible. The limits of our own performance. And those of our loudspeakers. We design, we develop, we try out. We learn to master rules. We pave this path in order to always go one step further and leave conventions behind. Our new, patented hyperspherical horn takes it even one more step further. It is the capstone of our expertise. This asymmetric horn extends beyond the 180 degree horn opening of the classic spherical horn shape. In addition to the elegant and elaborate appearance of this design, there are also significant technical advantages. The transmission range of our hyperspherical horn increased from the usual three to now five octaves. Minimal distortion and tonal discolouration, which usually emerge at the end of the frequency ranges of the classic horn technology, are a thing of the past with this new horn design. 


Because the music signal is now transmitted over a much larger frequency band with maximum dynamics, the sound is even more natural. That’s why the hyperspherical horn can be precisely combined with other drive units. This applies to our woofers as well as to our ion tweeter.

The processing quality of the elaborate resonance-optimized designs reflects highest craftsmanship expertise and makes our hyperspherical horns unique. With them, we are in the process of writing history in the world of hi-fi. 

Ion tweeter


We have always crossed borders to set new standards in terms of spatial high frequency imaging. With our ion tweeter we have created a milestone. It is a truly unique work of art in its advanced technology and breathtakingly fast and open sonic performance.


Our ion tweeter is the dream of every speaker manufacturer. The massless diaphragm generates the fastest possible high frequent signal without any delay. Through a pulsating plasma flame, we excite the air, creating a musical signal that embodies the world-wide reference system for high-frequency reproduction in terms of transparency and audibility. For that, our ion tweeter uses an electric arc to transmit the music signal to the air at the speed of light.


When it comes to intensify the depth, clarity, and realism of music by combining advanced acoustic technology and strategically positioned drive units, a speaker designer must discover new and unconventional paths. This is our conviction. Our ion tweeter sets us clearly apart from all other systems. With it, every striking of the piano keys, every plucking of the guitar strings, every tone from a horn instrument, every chorus, and every melody evolve with accuracy and texture, as intended by the artist.


As a premium manufacturer, our team of experts is fully focused on deepening and personalizing the relationship with our discerning customers – with musical experiences that will delight you all your life.



Our loudspeakers stand out from the crowd. Our timeless design enhances the efficiency of the sonic performance, originating from extensive computer simulations in which aesthetics and the highest level of acoustic rendition are the most important parameters. Clear lines emphasize the elongated shape.


The art of harmoniously matching all high-tech components in our loudspeakers columns to each other is not an easy task. In the end it’s us, who aspire to listen to an ideal authentic music signal. Our role model is the one-point-source. Just like it occurs in nature. It’s a composition of overtones and undertones, superimposing themselves in different octaves and being played back in absolute time coherence.


We have worldwide maintained the reputation that our loudspeakers resemble excellent music instruments with state-of-the-art technology and design of highest grading. The development, testing and manufacturing of the materials we use are subject to our strict standards of quality, fit and durability. Every single component is carefully selected for optimum performance and the longest product life possible.


From the positioning of sound-emitting diaphragms, through complicated electronic circuit design, to the use of resonance-optimized materials, we rely on our unsurpassed craftsmanship and groundbreaking innovations unparalleled in the audio industry.

Why are we striving for this meticulous diligence and pursuing absolute perfection in development and production? Music can change your mood, awaken memories and affect your well-being. It can cause you either goose bumps or tears. That’s why music and its lovers work so well together. Listen to your favorite singer, band or favourite composer. It’s your room. Your world. But what if you could do more than just listen to music? What if you could feel it, experience it and immerse into it? How about amplifying your relationship with music and enjoying a more immersive acoustic experience in your listening environment? On our end everything is about the absolute musical experience – the feeling of being in the middle of the event. Our loudspeakers are designed exclusively for your emotions.

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