BDNC Now Shipping STAPEZ Flat Glass-Composite Speaker Drivers

March 19 2020, 00:45
BDNC Holding Ltd is now in production of its highly advanced flat glass-composite diaphragm woofer. Available through Digikey under the brand STAPEZ, this new innovative drivers use ultra-thin tempered glass as the diaphragm, combined in a low-profile woofer able to produce extended bass response. At present, the smallest size is 80 mm × 20 mm × 7.2 mm but BDNC is also working on smaller models and already launched a 40mm headphone driver using the glass-composite technology.

BDNC (Holding) Limited derived from Beijing Design and Creation Electronics Co Ltd, founded in Beijing as an algorithm provider for semiconductor companies. Following a management buy-out (technology and assets) by the company founder in 2007, BDNC successfully raised the capital needed to pursue its separate research activities and was finally registered in Taiwan. There, the company established technical facilities to expand its business from Digital Signal Processing (DSP) and Mixed-Signal research, also into electro-acoustic, product development, production and commercialization.

In 2011, BDNC (Holding) Limited first introduced a Very Low Ohm (VLO) speaker design for audio systems, and in 2016, following an extended R&D effort focused on using ultra-thin tempered glass, the company successfully introduced a new generation of flat thin speakers able to generate extended bass response. The new technology is currently available in three different driver sizes, from the smallest FP-SPK-S (80x20x7.2mm) model, to the intermediate FP-SPK-M (160x40x17mm) driver and even a larger FP-SPK-L (584x92x25mm) speaker size. 

BDNC has now extended its innovation roadmap from glass cone speakers to also serve the headphone market with high end drivers, and his currently working on VLO Class-D and Class-AB amplifier IC development and productization.

BDNC is actively advocating the use of thin glass (amorphous SiO2) as the sound radiating diaphragms for novel speaker drivers designs, as well as improving the performance of traditional designs. The company's glass diaphragm is currently available with a thickness from 0.8mm down to 0.03mm, allowing it to be used as a flat or (traditional) cone diaphragm, in standalone or composite form.

As BDNC explains, proven advantages of its existing STAPEZ flat glass-composite diaphragm implementation include improved speed of sound propagation in shear mode, density (impacting directly speaker efficiency), mechanical strength (stiffness, Young's modulus, shear modulus, elongation before break, degree of bending before break, yield strength, creeping properties, fatigue properties... etc.), and internal loss factor (natural sounding).

The material also shows strong advantages in terms of minimum production and working thickness, facilitating mass-production, and adhesion properties, reducing the production cost and yield, while also showing improved thermal properties characteristics. Finally, the material and product production shows no significant health or environmental concerns, paving the way for new potential application areas at competitive prices. As Walter Kawai Chu, BDNC's president and founder notes amusingly, "If price or health is not a concern, diamond, beryllium, or sapphire may offer better performance."

Detailing a bit more the characteristics of their new STAPEZ FP-SPK-M flat glass-composite woofer (18mm x 166mm x 46mm), BDNC reveals the use of Schott AS87 Glass over aluminum alloy foil with a total thickness of 0.3mm and mass of 3.4g, generating 8mm X-max and very high continuous force (2.84 kgF, 6.44kgF transient) with continuous power handling rate of 35W (180W transient). Other key parameters reveal high Mms (mass) for low Fo both in free-air and in-box, plus high BL (BL=4.34) for maintaining the demanded sensitivity. 

This STAPEZ FP-SPK-M woofer is designed to work with extremely thin (≥20mm) and small (250cc ≤ V ≤ 1500cc) passive-radiator or sealed box designs, according to the company's miniMAX speaker principles, which determine that the best results should be achieved with a combination of offering the best possible specs (including frequency response, output loudness, size, geometry, and weight) at the correct price, taking into account what can be done with DSP or analog processing in order to achieve the best possible combination between the physical design and the sound quality of the final product.

Samples of the FP-SPK-M speakers (17.2 x 160 x 40mm), and 40mm glass-cone full-range headphone drivers are available from Digikey.
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