Whats the Significance of a Low MPO?
Physically, a low MPO means that the maximum SPL that is produced by the hearing aid is limited. In most cases, an MPO of 100 dB SPL is low. Electroacoustically, a low MPO means saturation or compression limiting is reached easily with everyday sounds, including speech at a conversational level. Functionally, the MPO on a hearing aid is regarded “low” if the maximum output of the hearing aid is below the wearer’s loudness expectation despite attempts to adjust the gain higher. This is especially true for those with a significant degree of hearing loss and when the input is above a conversational level. The output of a hearing aid depends on the input level and the gain of the hearing aid. The MPO limits the output. This means that, as long as the output is below the MPO of the hearing aid, any changes in the input level or to the gain to the hearing aid will be accompanied by a corresponding change in output loudness that the listener should appreciate. Thus, for someone with a mild de
