Growing up, Ole Siig was influenced by his creative and musical father Helge Siig, who developed X-Ray equipment used for quality assurance of airplane wings. His father instilled him to his passion for functionalism, design and attention to detail. During the late 1950s and into the 60s, as a hobby, Helge created unique furniture that integrated form and function.

Helge was also an accomplished musician. Hence, the interest in music, audio, design and science all came naturally. Being fortunate to having raised children with musical talent, Ole's home has been filled with the inspirational and initially scratchy sounds on the violin and fumbling fingers on the piano, later developing into fully accomplished and enjoyable performances that tuned his ears to how instruments really sound.

In his teens, Ole built several box type loudspeakers, later an active analog phase-linear crossover and other audio electronics, all as a passion. During high school he worked the evening shift at the Peerless loudspeaker factory in Denmark, responsible for mixing diaphragm paper pulp and managing the machine stamping out and heat forming the center spider for a series of woofers.

Ole's career, until now, went from electrical engineering and computer science to designing and product managing software solutions for the shipping, financial, commodities, energy and law sectors. This experience has equipped him with deep research, technical skills and familiarity with the product life-cycle process. About six years from idea to research and development lead to a fundamentally new patented loudspeaker concept and the launch Treble Clef Audio^®.

Treble Clef Audio began with no intention of being a commercial loudspeaker brand. The TCA-M Active Loudspeaker grew out of a personal passion project—an engineering and design journey pursued for its own sake, not to meet a market demand or hit a price point. What began as a hobby evolved, through careful thinking and countless refinements, into a low-volume, build-to-order product designed for listeners who value authentic, emotionally engaging sound.

From the earliest sketches to the final listening tests, the TCA-M reflects an end-to-end advanced engineering process that few companies would attempt. We control the complete transfer function—from the incoming electrical signal, through all electronics, ultra-short signal paths, and precisely matched drivers, to the enclosure principles, dispersion characteristics inextricably tied to physical shape, and integrated acoustic output using advanced Digital Signal Processing (DSP) to achieve what physics does not allow with a conventional approach. Every step is optimised as part of a single, coherent system.

This holistic design is shaped by years of listening to acoustic instruments in every imaginable space—from barns to record stores, galleries to purpose-built concert halls. In those real-world experiences, I found that after only a short time my subconscious mind understood the room, leaving me free to focus entirely on the music and its emotions. Yet with both my own earlier loudspeaker designs and many commercial models, that natural ease rarely happened; the speakers would interact with the room in a way that constantly reminded me of the playback system. This led to a key question:

What are the acoustic behaviour differences between natural, well-known sound sources and loudspeakers reproducing them—and why do so many speakers turn this into a muddled, room-coloured experience?

The TCA-M and our Sound by Design® patented acoustic platform it is built upon is my answer: a design that reproduces those familiar cues so faithfully that the brain accepts them as real, allowing the music to take centre stage.

Sound by Design® takes into account not only how sound behaves in rooms, but also how humans perceive and recognise complex, learned patterns of sound—from the timbral fingerprint of an acoustic instrument to the subtle resonance of a key bundle landing on wood, metal, or stone. The TCA-M reproduces these cues with microsecond precision, preserving the living interplay between harmonics and transients so that listening becomes an instinctive, immersive experience.

Commercially, few would start or operate a company this way. In most cases, products are designed backwards from a target retail price, with compromises layered in to protect margins. The TCA-M was developed forwards—from a blank page and a set of ideals—through iterative problem-solving and deep engineering insight.

By building to order and selling direct, we bypass the costly and now declining distribution–reseller model, where manufacturers are forced to accommodate supply-chain discounts that put serious strain on profitability. That traditional structure makes delivering genuine value nearly impossible; our approach ensures the customer’s investment goes directly into performance, craftsmanship and personalised services, not layers of markup.

The result is a loudspeaker that delivers exceptional value relative to its price and rarity. Built in limited numbers, each pair is a piece of functional sculpture—crafted for lasting performance, emotional realism, and seamless integration into refined architectural spaces.

Every TCA-M pair is made to last with personal customer styling preferences, supported by a comprehensive warranty, ongoing service, and an upgrade programme designed to keep it performing at its peak for decades. Our aim is for each loudspeaker to be cherished and passed on, much like a piece of classic designer furniture or fine art.

The TCA-M is more than a product. It is the outcome of years of focused thinking, learning, and perfecting—a testament to what can be achieved when every stage of the journey is guided by purpose and precision.