This drill will teach you to tell the difference between a split first heart sound and a fourth heart sound. A fourth heart sound is heard just before the first heart sound and is lower in pitch (~60 hz) and shorter in duration. In this drill we will contrast a cycle with a split first heart sound and one with a fourth heart sound and an unsplit first heart sound.
Listen as long as you want. When you are confident that you can detect the difference, move on to the test. In the test we will play cycles randomly and ask you to tell which is which.