Harry F. Olson
Dr Harry Ferdinand Olson, E.E., Ph.D. (December 28, 1901 – April 1, 1982) was a prominent engineer and inventor with RCA Victor, the Acoustic Research Director of RCA Laboratories, Princeton, and a pioneer in the field of 20th century acoustical engineering[1] notably in the fields of high-fidelity, digital music synthesis, microphones, loudspeakers, acoustics, radar, submarine communication, magnetic tape and noise reduction.
Olson wrote ten books including Dynamical Analogies,[2] on electrical-mechanical-acoustical analogies, and had over one hundred patents.
High Fidelity Demonstration[edit]
Shortly after World War II, Dr. Olson conducted an experiment, now considered a classic, to determine the preferred bandwidth for the reproduction of music. Previous experimenters had found that listeners seemed to prefer a high-frequency cutoff of 5000 Hz for reproduced music. Dr. Olson suspected that this was likely due to imperfections in the sound, especially in the higher frequencies, as reproduced by equipment in common use at the time. These imperfections included clicks and pops (from 78 rpm recordings), added noise (from AM radio broadcast static), hiss and harmonic distortion (from amplifier circuits), and non linear frequency response from primitive loudspeaker designs. If the sound was free of these problems, he reasoned, listeners would prefer full frequency reproduction.
In his experiment, he set up a room which was divided diagonally by a visually opaque but acoustically transparent screen. The screen incorporated a concealed low-pass acoustical filter having an upper frequency cutoff of 5000 Hz. This filter could be opened or closed, allowing either the full range of frequencies to pass or the range only below 5000 Hz. At first, a small orchestra sat and performed on one side of the screen, while a group of test subjects sat on the other and listened. The listeners were asked to select their preference between two conditions: full bandwidth or restricted bandwidth. There was overwhelming preference in favor of the full bandwidth. Next, the orchestra was replaced with a sound-reproduction system with loudspeakers positioned behind the screen instead. When the sound system was free of distortion, the listeners preferred the full bandwidth. But when he introduced small amounts of nonlinear distortion, the subjects preferred a restricted bandwidth, thus demonstrating clearly the importance of high quality in audio systems.[1]
As a result of this experiment and the work of others, such as Avery Fisher and later Edgar Villchur, high fidelity sound recording, transmission, and reproduction equipment saw increased investment, development, and public acceptance in the following decades. The design and manufacture of everything from microphones, to tape recorders, vinyl records, amplifiers, and loudspeakers were impacted.
Influence on High-Quality Modern PA Systems[edit]
The Grateful Dead's early sound engineering team, led by Owsley Stanley and Dan Healy, considered Harry Olson's 1957 book "Acoustical Engineering" the Dead's "bible" on building the Wall of Sound (Grateful Dead), the first touring sound system that allowed a band to actually hear themselves and have the audience hear what the band was hearing on stage.[6] The band made copies of the book for all of the Dead's sound crew.
The Wall of Sound influenced all modern high-quality PA systems for live music.