The Acoustical Society of America has created the most important forum for advanced discussions and presentations on instrumentation and measurement techniques over the past 50 years. We have all had great benefit from this—not least within the area of transducer development. It is the intention of this paper to give a brief summary of important steps in transducer development and the state of the art in calibration accuracy, where absolute calibration today is reported with standard deviations less than ±0.01 dB. New mircophone development is reported and a history of analog detectors brought up to date.