Ushindi

Why it is renowned

Ushindi, Swahili for victory, is Purifi's name for drivers built to remove sources of distortion, and the maker counts it the first technology to make long-stroke drivers work well: a small long-stroke cone can now outperform a large short-stroke one.¹ The American magazine audioXpress has measured six Purifi drivers in its Test Bench column and judged the 10-inch woofer another very high-performance design, from a line it found built to an outstanding standard.² The Danish speaker brand Radiant Acoustics chose an Ushindi woofer for its first loudspeaker, the Clarity 6.2.³

The story

Every Ushindi driver combines Purifi's patented PureDrive motor, a cone shape found by mathematical optimisation and the NeutralSurround, and each is marked by a red magnet top plate.¹ The range covers midrange units, woofers and long-stroke woofers, with paper or aluminium cones, raw or coated.¹ Speaker makers can buy the drivers or license the technology.¹

The surround alternates sections of forward and reverse roll so that the cone's working area stays nearly constant as it moves.² In the motor, a neodymium magnet takes the place of most of the pole piece, which cuts the coil's inductance and its change with position, and copper rings shield the iron from the coil's field; Purifi says the motor reduces both position- and current-dependent force factor by a factor of ten or more.²¹