The expression 'acoustic optimization' can be applied to numerous different disciplines within the field of acoustics. From seismic waves, sound in the atmosphere through bioacoustic, psychoacoustics, and room and theater acoustics over shock and vibration in mechanical structures. This paper deals with the latter. Sound generated by vibrating structures is often called noise which is to be minimized. However, not all vibrating structures produce noise, for example the violin is also a vibrating structure that in most people's opinion produces sound called music. In the case of the violin, great effort is made not to minimize but to optimize the sound, i.e. to get the 'right' sound out of the structure. Acoustic optimization within this discipline involves automatic changes of structural design variables to obtain minimum or specified sound in specified regions inside or outside the structure. Examples of problem formulations and some theoretical considerations in the field of acoustic optimization in connection with vibrating mechanical structures will be pointed out. Four simple test cases are included as numerical examples of the method proposed.