The two-channel FFT analyzers have revolutionized the measurement technique used for mechanical measurements. Recursive digital filter technique is in general use within acoustics. However, the true real time capability, eliminating the use of window functions like f.ex. Hanning along with born logarithmic frequency scale, offers great advantages for the measurement of mechanical vibrations. The measurement of vibrational net power flow, vibration modes and stress intensity by mechanical transducers will be discussed.