Accuracy of the quantities measured by four vocal dosimeters and its uncertainty.

Although vocal dosimeters are often used for long-term voice monitoring, the uncertainty of the quantities measured by these devices is not always stated. In this study, two common vocal dosimetry quantities, mean vocal sound pressure level and mean vocal fundamental frequency, were measured by four vocal dosimeters (VocaLog2, VoxLog, Voice Care, and APM3200). The expanded uncertainty of the mean error in the estimation of these two quantities as measured by the four dosimeters was performed by simultaneously comparing signals acquired through a reference microphone and the devices themselves. Dosimeters, assigned in random order, were worn by the participants (22 vocally healthy adults), along with a head-mounted microphone, which acted as a reference. For each device, participants produced a sustained /a/ vowel four times and then read a text with three different vocal efforts (relaxed, normal, and raised). The measurement uncertainty was obtained by comparing data from the microphone and the dosimeters. The mean vocal sound pressure level was captured the most accurately by the Voice Care and the VoxLog while the APM3200 was the least accurate. The most accurate mean vocal fundamental frequency was estimated by the Voice Care and the APM3200, while the VoxLog was the least accurate.