[Mitral Area:  S1 is somewhat wider than usual and is louder than S2.  S2 is followed by an OS (opening snap). Some could mistake this for a split S2. There are no other sounds in systole or diastole; HR = 79 bpm]  

Notes: Did you notice, at about the 8^th or 9^th beat, a quickening of the beat?  Be sure your stethoscope’s ear tips are sealed well into the ear canals and the chest piece sealed snug against  “The Patient.”  Just a very small leak  significantly decreases your ability to observe low frequency sounds.  Check your stethoscope regularly for leaks in the stethoscope itself.  You can do this by putting one finger into the bell to seal it, one finger into one of  the ear tips and the other ear tip in your mouth (clean it first). Draw a vacuum  and stick your tongue into the ear tip. If it does not come off within 5 seconds, your stethoscope is pretty well sealed (remember to clean your ear tip again).