Methods for evaluation of wood's quality and technical fitness by using ultrasonic and other acoustic techniques are commonly used in practice all over the world. To this end, first and foremost, the following parameters are analysed: signal transition time, maximum amplitude of received signal, signal attenuation factor. Based on these parameters overall quality of wood can be forecast but types of wood defects cannot. As results from the recorded spectrum of signals propagated in wood followed by the spectrum analysis, it is also possible to predict anatomical structure of wood at the section tested. Based on preliminary model-scale tests using the Sylvatest Duo apparatus, a correlation has been found between wood's anatomical defects, encountered by the signal passing through the material, and the signal's time and frequency performance being analysed.