The influence of recording conditions on the results of acoustic analysis

For professional purposes, it is recommended to use a studio condenser microphone with a higher-end dedicated preamplifier. It provides the least sensitivity to the recording method, but requires good, flexible mounting on a tripod and elimination of low-frequency noise sources.

For semi-professional purposes or to exclude voices with a low fundamental frequency, a superior vocal dynamic microphone may be recommended. You should then remember to increase the distance between the microphone and the patient's mouth (min. 10 cm), which unfortunately affects the level of interference, or to compensate for changes in the characteristics of the microphone at the stage of numerical calculations when determining the parameters of acoustic analysis. A much better solution is to use a dedicated mic preamp with balanced input than a potentially slightly better sound card. A cheap computer microphone has good enough parameters to be used for voice analysis. Unfortunately, in combination with the built-in card preamplifier, it is characterized by a decrease in sensitivity for higher frequencies, which significantly lowers the values of acoustic parameters - especially NHR. Its use requires compensation of the frequency response at the stage of calculations. In addition, it is extremely sensitive to additional blows and interference from the connecting cable (thus requires additional protection with a sponge and an environment free of electromagnetic interference). The described problems can be eliminated by replacing the connecting cable with a better shielded one or removing the hum components at the analysis stage.

It seems necessary to introduce to acoustic screening analysis the mechanisms of compensating the frequency characteristics of the equipment and removing background disturbances - mainly mains hum.