A cut optimization system controls chatter in a machine tool during a cutting operation. A microphone is configured to capture acoustic noise emitted by the machine tool during the cutting operation and to generate an AC signal corresponding to the captured acoustic noise. A filter is configured to attenuate frequencies of the AC signal outside of a frequency band and a rectifier is configured to rectify the filtered AC signal into a DC component. A controller is configured to compare the DC component with a threshold value and, if the DC component is greater than the threshold, cyclically vary the rotational speed of a spindle in the machine tool from a commanded speed.