Subjective evaluation of a simple active noise control system mounted inside an earth moving machine cab

A series of experiments were carried out in order to verify the feasibility of an
active noise control (ANC) approach to improve the acoustic comfort at the
operator's station of a compact loader. For this kind of application expensive
noise control solutions would be too expensive for the market and therefore
unsuitable. Hence, a very simple active noise control layout using a single
channel feed-forward scheme was used. Its capability to reduce the dominant
low frequency noise components and the overall level within the space where the
operator's head is located during his/her work was experimentally verified.
Then, the modifications caused by this ANC system were subjectively evaluated
with regards to some important noise features (tiredness, concentration loss,
loudness and booming sensation) in order to qualify comfort and working safety
conditions for the operator.