I classify abnormal lung sounds as either harsh (ie coarser and louder than normal) or crackles (which can be fine or coarse).There is a tendency to think that harsh lung sounds would be caused by “dry” lung disease and that crackles would be due to “wet” lung disease but this is not the case. Harsh lung sounds can be caused by any parenchymal or airway disease probably due to increased turbulence from airway narrowing.These radiographs are from a cat with severe interstitial lung disease, either chronic asthma or neoplasia. He had very harsh lung sounds in all fields. On the radiographs you can see that there is a very marked bronchointerstitial pattern throughout the lung lobes.Referred upper airway noise can also make the lung sounds sound louder than normal so have a quick listen over the trachea and mentally subtract any upper airway noise from what you are hearing in the chest.