Harman Kardon
In 1959, Harman Kardon marketed the Citation II, an early ultra wideband stereophonic tube amplifier. Designed by Stewart Hegeman, it featured 60 watts/channel output with a frequency response of 18-60,000 Hz at 20 watt output. The company promoted their philosophy of designing high fidelity sound using amplifiers that provided widest possible audio bandwidth. Although the human ear highest audible range is around 20,000 Hz, the full range of sound goes beyond that with harmonics and overtones that may be beyond the hearing range of the human ear. These harmonics interact with other frequencies to produce audible secondary sounds or interference. Harman Kardon promoted the design in audio magazines and product brochures.
Tim Storms
Storms' Guinness World Record for the lowest note produced by a human was first certified in January 2002. Storms also holds the Guinness World Record for the widest vocal range for a male. His records have been published in the Guinness World Records 2006. He broke both of these records in August 2008. As of 2008, the new record for lowest note was 0.7973 Hz, and the new record for Widest Vocal Range For Any Human was ten octaves.