An improved pulse oximeter is disclosed. The pulse oximeter includes audio signal generation means, controlled by algorithms in a processing element which continuously transform the signals from the sensor into signal quality information. This information is converted into an audio signal and annunciated for the operator's use in guiding sensor placement. This signal quality information is available even in the absence of successful computation of pulse rate and/or oxygen saturation level. It furthermore can reflect signal quality changes that may be too subtle to be reflected in the typical numerical representation of pulse rate and oxygen saturation trend. The audio representation of the signal quality can further be modulated to convey other system and/or physiological status and alerts.