KOI HQ Driver Technology


With a cone area of approximately 2.5 square inches, the KOI HQ driver is the world’s smallest transducer capable of full-range (wideband) performance.

Technical Highlights

Computer-generated non-resonant cone geometry: The unique shape of the KOI HQ driver cone was developed with the aid of sophisticated computer algorithms. The geometry minimizes resonance modes, which contribute greatly to non-linear behavior in conventional circular cones. The result is smoother amplitude response over a wider range of frequencies.

Patented heat transfer system: Drivers are ultimately limited in acoustic output by their power handling capability, and the problem is magnified in smaller drivers designed for wideband response. KOI’s patented heat transfer design employs advanced materials and an innovative physical configuration that reduce voice coil operating temperature, thereby significantly increasing power handling capacity.

A special x-ray technique was developed to improve the accuracy of the fabrication process. This brings the manufacturing tolerance limit to within 1 dB of reference—a level of precision unmatched in the industry. In the past, such matching could only be achieved at the expense of a high rejection rate.

State-of-the-art listening analysis projects played a crucial role in the development of the KOI HQ driver as well as KOI’s proprietary Human PsychoAcoustic® technology.