Four pieces of halved blank for violin making, two cut from tone spruce wood and two from maple wood, have been investigated. The method used for determination of the elasticity constants of the wooden plates is based on the knowledge of eigenfrequencies and shapes of the first few vibration modes. The electronic holography system visualizes the time-average interferograms in real-time. The electro-optical measurements are supported by the separation of eigenmodes electroacoustically. The frequencies are compared with the results of the Chladni method and a measurement of frequency responses. The obtained knowledge can be helpful for the selection of wood plates before they are used in a production process.