The methods of noise attenuation can be separated into the two groups: active and passive methods. The active methods consist of the generation of sound that is out of phase with respect to the primary sound produced by the source. The passive methods of noise attenuation can be divided into the following groups: Noise minimization at sources, Conversion of acoustic energy into another kind of energy and changing the direction of acoustic field propagation and dissipation of the energy outside a protected area. Localization of noise sources using a probe is a very effective method. Especially worth to be recommended is the second method which enables one to detect even small defects of sound-absorbing shields with the help of a probe coupled with a narrow-band analyzer. Localization of the point of the highest noise level often enables one to find a secondary resonant source hard to be indicated through any other method.