Conventional hearing instruments, until approximately 1984, were the backbone of the hearing aid industry. The technology is termed conventional because these instruments utilize basic linear or analogue/fixed electronic circuitry. These linear instruments, while adjustable for volume and usually for slope (tone) process sound in a straight mathematical fashion, providing in theory, equal amplification at all key frequencies in the speech range. Usually, these products are selected by overall acoustic gain (amount of amplification required), slope (frequency response) and total output. The circuit and individual models are prescribed for the patient based on their individual test results and hearing evaluations.
This first level of technology is available in all styles of hearing aids from B.T.E. (Behind-the-Ear) to C.I.C (Completely-in-the-Canal) (smaller) models. Usually, linear products are not ideally suited for patients who recruit, have loudness tolerance problems or steep slope losses. However, these aids are currently the lowest in price in the marketplace which is an important consideration. They are widely used in Europe and in lesser developed countries. Market share of conventional products is steadily declining in the United States with the recent developments in 100% Digital and Programmable technology.