Great Vintage Loudspeakers

Great Plains Audio’s 399-Series of high frequency compression drivers are designed to give excellent audio reproduction at high output levels over a wide frequency range with extremely high efficiency. When used with constant-directivity, sectoral, or other appropriate horns, the 399-series HF Drivers provide uniform response that is superior to all other large-format drivers available today. When combined into system that incorporate low frequency loudspeakers and dividing networks, the Great Plains Audio Models 399-8A and 399-16A High Frequency Compression Drivers provide the natural sound reproduction demanded by even the most discerning listeners. Designed for use in large-format sound reinforcement systems, where high-level output is required, Great Plains Audio’s 399-series High Frequency Compression Drivers will provide the most realistic sound reproduction possible today without the induced distortion found in drivers that have larger diaphragms and 2-inch exit throat diameters.

‘Superior HF Reproduction

All high frequency compression drivers consist of three basic parts: (1) the diaphragm; (2) an acoustical transformer (also known as a phasing plug); and (3) a motor (the magnet). All Great Plains Audio high frequency compression drivers are designed and built using the finest engineering methods and materials to the highest manufacturing tolerances in the industry.

The focal point of our 399-series HF Drivers is the diaphragm/voice coil assembly, the design of which is critical to accurate sound reproduction. Even though many manufacturers today try to claim they have discovered a superior method of high-frequency reproduction, Great Plains Audio has chosen a different paradigm. By utilizing only the finest, time-tested materials and manufacturing methods in the construction of it’s high-frequency section, including: (1) an all-metal Pascalite™ dome structure; (2) a tangential compliance; and (3) a voice-coil of 2.88-inch edgewound copper clad aluminum ribbon, our 399-series of high frequency drivers exhibit superior sound reproduction of the frequencies above crossover at high levels.

In order to assure that the sounds being generated by the diaphragm leave the loudspeaker in proper phase alignment, the 399-series use our exclusive RADIALWAVE™ phasing system, which ensures maximum high frequency reproduction while maintaining proper phasing and smooth overall response to 15 kHz.

Finally, a powerful magnet structure combines the other two portions of our 399-series of high frequency compression drivers together and transforms them into a system that reproduces the sound in a natural manner. Each 399-series high frequency compression driver has an efficient magnetic structure utilizing a 6.7-pound ferrite magnet with a flux density of 22,500 gauss.

Working in tandem, the Pascalite™ diaphragm, RadialWave™ phasing system, and the small yet powerful motor structure ensure that the GPA Models 399-8A and 399-16A High Frequency Compression Drivers are capable of uniform, peak-free reproduction throughout the range of human hearing, thus making them excellent choices as the high frequency components in large sound system environments where high output is also desired.