Construction machine’s engines generate low-frequency sounds, which accordingly cause discomfort to the driver inside cabins. In the present study, a simple adaptive active noise controller, namely, a single-frequency adaptive notch filter (SAN), has been introduced to mitigate low-frequency sounds below 100 Hz within a chamber. Controlling sound is produced according to the internally generated reference signal composed of two sine waves which have 90 degrees of phase difference to each other, which makes the control performance stable. In addition, frequency change of the target noise is predicted in real time by detecting engine speed. Numerical simulations are performed for checking operation of the proposed controller. Experiments are also performed for the active control of reproduced engine noise generated by a single sound source.
