The advantages of the eccentric cone, which has the drive points of the diaphragm offset from the central axis, are put to use in the unit’s sound production by effectively dispersing the diaphragm’s divisional vibrations (high level resonance). This eccentric cone technology achieves flat and smooth frequency response with few of the unavoidable peaks and valleys of common dynamic, circular speakers. Consequently, because the actual frequency range (flat response region) in each unit has been expanded and uniform high purity sound quality is obtained in all tone ranges over the width of the frequency range, the degree of freedom in the crossover layout has increased by an order of magnitude.

     In a car speaker, where getting the installation angle to meet the listener face-to-face can be hard and the sound is easily subject to the diffused sound reflection of the window glass, how well these directional properties can be controlled will have a profound effect on the acoustic field and imaging. PPC speaker technology, which exercises directivity control that takes advantage of the eccentric cone properties in all units, achieves a high level of acoustic field and imaging to eliminate any need to rely on an excessive amount of digital tuning. Another good point about the eccentric cone method is the ability to do fine tuning of directional properties through rotation of the unit at its installed position.

By adopting the same structure, the same materials and the same magnetic circuits in the 5cm tweeter, 13cm midwoofer, and 18cm subwoofer, we have successfully achieved the essence in tone quality coherence spanning all ranges, a longstanding aim of multiway systems. Of particular note is that the tweeter has crystallized our groundbreaking design and production technology by compressing the eccentric cone, with its extremely high precision requirements, to an inner diameter of just 5cm. Japan’s audio technology, unrivaled in the world, has given birth to the Bewith-exclusive all eccentric cone system.

Another major feature of PPC speaker technology is that the recommended crossover point between the tweeter and midwoofer is set to 800Hz, an exceptionally low value compared with common two-way systems (normally set at around 3kHz to 5kHz). This is done by using the all-eccentric cone method that obtains uniform high-purity sound quality across virtually the entire frequency range. Setting the crossover point, which is subject to phase drift and frequency response undulation, below the medium-high sound range between 1 and 5kHz where auditory perception is most acute and seamlessly reproducing sound from this 800Hz point to the end of the high region in a single unit allows you to listen with pleasure to an unexaggerated natural tone quality and the true acoustic field.