The driver. "An electrodynamic transducer is a system which consists of a relatively small number of elements. Each exerts its influence on the overall parameters and thus sound quality. The task of the developer is to make this system work optimally which is possible only with perfect selection and coordination of all elements. Each element is its own system consisting of a particular geometry and properties determined by the material it is made from. Conditionally we can divide the driver into two parts: movable and stationary. The stationary part includes the motor system and basket. The movable part is everything that moves to create sound. Based on this principle, let's consider the design of the Binom-A1 driver.
"The Binom-A1 is unique in many ways. During its development, I took into account many years of prior experience in designing loudspeakers. I paid much attention to things which at first glance seem very little. Even the name Binom is no accident. It points at the multi purpose of sub elements which perform two or more functions simultaneously. The driver basket is made from a CNC-machined aluminum alloy which we anodize black. To give the driver visual elegance once installed, a special diamond groove gets applied to the front after the anodizing bath and the company specifics laser engraved. For proper sealing with the cabinet, the driver uses a precision rubber O-ring whose air-tightness relies on having a perfectly flat surface.
"The magnetic system of the driver is a half-closed type built on the basis of two symmetrical neodymium magnets (1 and 2). The magnetic field is formed using a U-shaped magnetic circuit (3), core (4) and upper pole plate (5). This geometry achieves absolute symmetry of the magnetic field at its upper and lower points, thus perfectly linear movement of the voice coil. No matter where the voice coil is located, it remains surrounded by the very same material, hence the same magnetic field parameters."
"Let's look at the task of the magnetic system where I again use the word 'system' whilst many manufacturers use only 'magnet' to assign zero significance to the material of the magnetic circuit. In addition to establishing the necessary parameters of the magnetic field, we must reduce the influence of the secondary variable magnetic flux generated by a moving voice coil. Consider this process in more detail. Whenever a ferromagnetic material magnetized by a constant magnetic field is exposed to an alternating magnetic field created by a voice coil, it induces an additional secondary alternating magnetic flux. This in turn induces a secondary current in the voice coil to distort the main signal. Under the influence of this flux, eddy currents or induction arises in parts of the magnetic circuit whose direction coincides with the driver's axis. To eliminate this breaking effect in the Binom-A1 driver, its core and upper flange are made of a set of glued encapsulated plates of a special precision electro-technical alloy which increases the electrical resistance of the elements of the magnetic circuit in the axial direction to eliminate the effect. Iron is present only as an alloying element in the alloy from which parts of the motor are made. In short, we created an anisotropic material with directional properties. This also correctly forms the magnetic field itself whose force lines expand properly in the exact radial direction.
"The main moving part of the Binom-A1 is based on a composite flat diaphragm. The composite is an ultralight balsa wood plus special aluminum-beryllium alloy from the aerospace industry. The photo shows how due to the large internal tension in the latter material, it has a naturally curved shape. The diaphragm consists of two parts. Its central part (1) is rigidly connected to the voice coil former (2) from the inside to create an almost autonomous high-frequency emitter. On the other hand (external), the voice coil uses a special element having a certain strictly defined degree of elasticity (4) which connects to the second part of the diaphragm (3). This part additionally connects to the voice coil using a traverse (5).
"This construction determines the mode of operation of the diaphragm to completely exclude the break-up region and modal zone of operation, its so-called multi-modal mode. Instead this construction in combination with specially selected materials and the geometry of all elements of the diaphragm divides the bandwidth into three modal zones. The first is 0-2'000Hz across which the membrane behaves purely pistonic (left). In this zone, all diaphragm points move identically relative to the stationary elements. Due to the optimally selected materials of the diaphragm as well as its large thickness, nonlinear distortion in this range is negligible. The second zone is 2'000-8'000Hz (center). Here the diaphragm works as a bending-wave emitter. The maximum movement of the diaphragm is achieved in the center. The third zone is 8'000-28'000Hz (right). Thanks to the special elastic element (5) which in this case becomes the suspension across this range, only the central part works which is rigidly connected to the voice-coil former. To smooth out the frequency response, the entire inner diaphragm is additionally covered with a thin layer of wood (7)."
As Oleh Lizohoub laid out in unusually transparent fashion, the Binom-1 speaker was truly conceptualized front to back as a complex holistic system whose many interlocking parts each play a vital role on their own and in how they interact with all the other parts. Such performance is clearly far from accidental. It is only possible with such a systemic approach plus unique solutions if one wants to further the art in 21st-century single-driver speaker designs.
In my book, mission accomplished – and with bravura!
