Abstract
The main purpose of this report is to provide a deeper and more adequate understanding of active noise control (ANC). ANC is now developed in many directions; many ex-periments have been done, proving that several kinds of noise and vibration can be at-tenuated substantially by active devices. One of the authors recalls the origins of his own method, which had been applied and developed in acoustics by G. Mangiante and G. Canevet becoming then the “JMC theory.” This theory has been recently reformulated in a set of three theorems on “field reshaping.” The first theorem of Field Reshaping is analyzed. It leads to a very general “designer's equation” which can be considered as the key of most active control systems.
