A portable machine for delivering golf balls one at a time onto a tee or a surface simulating a fairway. A non-linear behavior of products and parts is reproduced through modeling. The electrical processing circuit is coupled with the load indicator and receives the output signal. Measurements of hydrostatic pressure are converted into equivalent circulating density measurements which in turn are used in calculating the sweep efficiency. In the error minimization computation, a theoretical impedance spectrum is calculated for at least one of the material samples, based on the impedance spectrum measured for the material sample, as well as the starting values for the components of the respective circuit equivalent, and fit values are determined for the components of the respective circuit equivalent.