Abstract: A method for non-destructive testing and for quality checking solid materials in which an acoustic contact is formed during the measurement between a converter and the material, this contact being stabilized by imparting vibratory oscillations to the converter relative to the material being tested. Then the moment of the formation of a high-quality acoustic contact is determined by an abrupt decrease in the rate of the test signal amplitude change. The vibration is discontinued, and depending upon the accuracy of measurement required, the test signal parameters, which carry information on the properties of the article being tested are measured either directly upon interrupting the vibration, or after a time interval sufficient to reduce the internal stress of the converter created due to its deformation resulting from vibration and pressure against the article.