Auscultation is widely performed but its interpretation in chest diseases is amongst the most difficult and subjective of assessments, once again there is no substitute from gaining experience in listening to chests in both disease and in health.
Using the diaphragm of your stethoscope, auscultate over the anterior chest, again moving side to side for comparison and starting at the apices. At each position listen to at least one or two complete respiratory cycles.
Normal lung sounds are described as vesicular. They arise from turbulent flow of air in the larger airways. Airflow in the smaller airways and alveoli is laminar and produces little noise. Aerated normal lung tissue filters out the high pitched component of the turbulence and thus what you hear at the chest wall are low pitched sounds with no pause between inspiration and expiration. With experience one is able to get a feel for how “loud” or “intense” these normal breath sounds are, given the fact that they will vary with the depth of respiration and in relation to the proximity of the stethoscope to large airways.