The Beginning of My Passion

As a child I loved solving puzzles and being active with wood. Actually quite obvious as the son of a craft carpenter. Listening to music became a habit as a child and from that perspective it is only a small step to building your own speaker cabinets. Enthusiasm and passion were enough to more than bridge the gap in knowledge. I put together a lot through trial and error. Naturally, I often found the sound quality lacking, but visits to HiFi stores exposed me to the marvels of high-end audio and the extraordinarily special sound production of top amplifiers and magnificent speakers. I aspired to someday own such superior equipment.

Fast forward to 1989: I stumbled upon a DIY loudspeaker magazine and was instantly enthralled. I resolved to construct my own loudspeakers, aiming for a design that was both impeccable and emotionally resonant. After all, music stirs our emotions.

I considered various designs, finally settling on a pyramid-shaped cabinet. Not only was it aesthetically unique, but it also offered advantages like a slanted speaker front which addresses the common issue of downward sound dispersion. Plus, the pyramid's structure is naturally sturdier than traditional cabinets, reducing panel resonances.

My initial cardboard prototypes felt too mundane. Serendipitously, one of the models unfolded partially due to weak glue, providing the foundation for my ideal design. Once perfected, I estimated its real-life size to be around 1 to 1.3 meters.

With the design set, I began exploring high-end DIY loudspeakers from brands like Scan-Speak, Eaton, Vifa, and more. I was particularly struck by the Vifa Basis and the Vifa Format. While the Format excelled in higher frequencies, the Basis had a rich, deep bass. Combining their strengths became my goal.

To achieve the Basis's bass in the Format, I could either modify the woofers and filters or expand the cabinet volume. I chose the latter. Using my pyramid design, I calculated space for the tweeter, midrange, and woofer sections. The estimated total internal cabinet volume was about 100-120 liters, roughly 40 liters more than the original Vifa Format.

With no advanced software available, I meticulously performed calculations by hand. These formulas were later programmed into GW-Basic to determine precise internal partition heights. The resulting internal volume was approximately 115 liters—45 liters more than the original design. My intent was to expand the bass reflex section to 65 liters. By fine-tuning with plastic sacks filled with silver sand, I could adjust the bass output to suit my room's acoustics. On average, I tend to reduce the bottom part by 10-15L. Although it might seem superfluous to have such a large volume of 65L, it provides the flexibility to add a significant amount of weight and mass to the bass chambers.

The Rovaha Format distinguishes itself by offering a balanced, natural sound and a robust design. This can best be described as "a scalene hexagonal truncated pyramid with a sloping top surface, where the height line is slightly recessed." The FUD (Female-Unfriendly Design) ensures the top section remains free from flowers, plants, picture frames, and so on.

There's more to the Rovaha Format's design than just striking aesthetics. Its super-rigid shape also ensures a balanced and crisp, clear sound. The shape and construction of the asymmetric panels directly influence the dispersion due to the tilted front baffle and side panels, minimizing internal sound waves, offering superior dimensional stability, and reducing panel resonances.

What makes the 1989-built format stand out?

The charm of this project is encapsulated by the original Vifa format setup. From that perspective, the Rovaha Format is essentially a Vifa format in disguise. That said, this masquerade vastly surpasses the original concept. The original Vifa Format's concept has been widely acclaimed over the past 20 years, receiving unanimous praise in various international magazines: a stable controlled soundstage, balanced and pure nature, high-end speaker setup, and consistently being labeled an absolute top-tier product.

The Rovaha design elevates the high-end Format performance even further. Developing a dedicated loudspeaker always poses multiple challenges. The design must be unique, the sound quality should be unparalleled, and it must be budget-friendly and suitable for a living room setting.

Cabinet Construction

The 115-liter pyramid-shaped floor-standing cabinet can be best described as a scalene hexagonal truncated pyramid with a sloping top surface, where the height of the top line is recessed. The fundamental construction of this ultra-solid cabinet comprises a single 22 mm MDF layer, complemented by an 8 kg/m^2 lead bitumen self-adhesive layer. The exception is the bass reflex cabinet, crafted from three 22 mm MDF layers. To achieve an uncompromisingly rigid cabinet structure, all MDF panels are bonded with polyurethane super glue. The asymmetrical panels ensure an elevated level of integrity, presenting a more cohesive and stable structure than standard rectangular cabinet shapes.

The tweeter and squaker share a 10L sealed compartment. Each woofer has its compartment: the top woofer resides in a 25L space with a perforated bottom panel serving as an acoustic filter, while the bottom woofer sits in a 65L bass-reflex compartment, which I later reduced to 43L.

The bass reflex port is front-facing, tuned to a low 22Hz, aiming to rival the Vifa Basis's clear and profound bass. Both the semi-closed woofer and bass reflex woofer sections are lined with lead bitumen and egg crate foam to curtail unwanted standing waves. The sealed tweeter and squaker compartments also feature lead bitumen and are filled with 225g of Bailys Long hair for optimal damping. In total, the cabinet weighs 80kg and is positioned on Soundcare speaker spikes.

Drivers

Tweeter

The Vifa HT-300 D is a 26mm (1”) double chamber ferrofluid soft metal dome tweeter with a aluminum alloy (Al/Mg) diaphragm. The double chamber technology enhanced a reasonable low resonance frequency (fs) 720 Hz. The black tri-spoke dispersion plate smoothens the high frequencies by dispersing in a wide (3D) angle as intended. With an outer diameter of 104 mm and a 6 mm thick face plate it fits like a glove in the front baffle and provides a highly detailed sound spectrum from 2.500 Hz. Listed specs 1.500 Hz – 45 KHz and a sensitivity (Lp) of 89 dB.

Midrange squaker

The beautiful Vifa MP130 midrange is a 130mm midrange polycone squaker with a magnesium cast frame. It provides a transparent image from 250 Hz up to 2500 Hz with a typical Scandinavian sound stage.

Woofer

The Vifa 21WP250 is a 210mm polycone woofer with a magnesium support frame. Just a bold and bulky woofer for the low frequencies all the way up to 250Hz. Beautiful woofer for classical enthusiasts and hard rock fans. The parallel woofer arrangement in combination with the bass reflex port lets you hear and feel the bass. Just lovely.

Crossover & wiring

All crossover components fully comply with the top quality of the system as built in 1989. MKT capacitors for the midsection while only MKP capacitors are used for the tweeter.

The two woofers are connected in parallel and are filtered with a slope of 12 dB per octave. At 250 Hz the Squaker takes over. At the bottom end, the Squaker is limited by the second-order network, while at the top end at 2.5 kHz it is also filtered with 12 dB per octave. The efficiency of the Squaker is adjusted to that of the woofers by means of a resistance. The tweeter takes care of everything from 2500 Hz onwards. This is the only one with a more complex crossover in the form of a third-order bridged T-filter.

Wiring

To squeeze out an extra bit of brightness of the tweeter I have used a silver-plated 0.96 mm2 speaker cable with Teflon insolation. Same approach for the midrange driver using 2.5 mm2 Cobra Silver cable. To support the lower bass concept both woofers are supported with 5mm2 Cobra Precision Monitor Streamline cable. Bi-wiring setup might be obvious, using the same cables, Cobra Silver Cable for middle and high, Cobra Precision Monitor Streamline 5 for bass.

How does it sound in 2023?

Powered by my Luxman amplifiers, the Rovaha Format speakers outshine most €2000 loudspeakers I've auditioned in recent years. It's still astonishing how effortlessly a 30-year-old concept continues to impress. Regardless of volume, the sound remains vibrant, crystal-clear, and palpable. Could it be improved? Absolutely! For that, I crafted a new pair: the SEAS Jenzen Next.