Electronic Hearing Aids
At the turn of the 19th century, hearing aids underwent a technological revolution by emulating telephone technology. The first electronic hearing aids used carbon microphones that modulated electrical current in response to sound pressure variations.
Hearing Aids Become a Business
Batteries and electronic components created a market for wearable amplification among people with hearing loss. Hearing aid design, which had previously been a craft or even art, changed into a manufacturing assembly process. Hearing aid manufacturing companies (e.g., Sonotone) appeared and pursued economic profit by seeking new technologies to create new products that were smaller, lighter, more powerful, and more efficient. Vacuum tubes were a major technical advance. The first wearable vacuum tube hearing aid came on the market in 1936. Beltone Hearing Aids was established several years later (1940) and quickly became one of the five largest firms in the industry (35 total firms) and one of the most innovative. It introduced the first all-in-one hearing aid in 1944, which combined batteries and transmitter into a single unit.
Beltone began a relentless march to expand the market and drive sales nationally which continues even today. In 1943, Beltone set up an exclusive dispenser network that was modeled on the insurance business. It was a franchise model in which franchisees received sales training and marketing support from Beltone in return for which they sold the company’s products exclusively.(2)
Other factors in the 1940s influenced the emerging hearing aid industry. Advanced munitions technologies introduced in WWII created a population of trauma victims with ear and hearing damage. Those soldiers were evaluated and treated in a new specialty ward at Walter Reed Hospital, which was staffed by an odd mix of hearing scientists and speech therapists. That alliance created a new specialty (Audiology) and a new armamentarium of electronic equipment to assess and treat hearing loss. As the dimensions of hearing loss were mapped with more precision, the demand for “selective” hearing aid amplification emerged. Manufacturers responded by diversifying and improving their product lines.
WWII technological innovation benefited the hearing aid industry in its efforts to expand and upgrade. In 1947, the US government released the first printed electronic circuits to private industry. Five years later, transistor circuits were developed that once again revolutionized hearing aids. In the space of one year, from 1952-1953, almost all hearing aids switched from vacuum tubes to transistors, which miniaturized them to the point that they became ear-level instruments rather than body-worn. Concealment became easier when hearing aids were incorporated into the stems of eye glasses. By 1959, 65% of all hearing aid sales were eye glass type.
Hearing aids were big business by the 1950s. Total US hearing aid sales reached $22.1 million in 1952, a 37% rise from 1948. By 1959, Dahlberg’s Miracle-Ear subsidiary had $100 million in annual revenues and was sold to Motorola, Inc.(4) In that same year, Beltone had 187 independent distributors under exclusive contract, along with 50 sub-dealer outlets.
References(1) Carbon hearing aids: General information. (2) History of Various Hearing Aid Manufacturers—General Information. http://www.hearingaidmuseum.com/gallery/General_Info/HACompanies/generalinfo-HACompanies.htm (3) Valente M, Hosford-Dunn H, Roeser R. (Eds). Audiology: Treatment (2007, 2nd Ed). New York: Thieme. (4) Miracle Ear. Wikipedia.