An experimental investigation has been performed, which revealed a considerable difference between the dynamic response characteristics of a tube-trauisducer system with the entrance in still air and one having an airflow across the entrance orifice, The differences observed could be explained theoretically by modifyink the existing calculation model for still air in such a way, that the interaction between the periodically in- and outflow at the tube entrance and the main flow is taken into account. Application of the present knowledge to the results of a joint ONERANLR investigation shows that satisfactory agreement is obtained between pressure distributions measured via tubes and via direct in situ pressure transducers.