By using the Zapruder, Nix and Muchmore motion pictures, the President’s location at the time the bullet penetrated his head was fixed with reasonable precision. A careful analysis of the Nix and Muchmore films led to fixing the exact location of these cameramen. The point of impact of the bullet on the President’s head was apparent in all of the movies. At that point in the Nix film a straight line was plotted from the camera position to a fixed point in the background and the President’s location along this line was marked on a plat map.[C3-327] A similar process was followed with the Muchmore film. The President’s location on the plat map was identical to that determined from the Nix film.[C3-328] The President’s location, established through the Nix and Muchmore films, was confirmed by comparing his position on the Zapruder film. This location had hitherto only been approximated, since there were no landmarks in the background of the Zapruder frame for alinement purposes other than a portion of a painted line on the curb.[C3-329] Through these procedures, it was determined that President Kennedy was shot in the head when he was 230.8 feet from a point on the west curbline on Houston Street where it intersected with Elm Street.[C3-330] The President was 265.3 feet from the rifle in the sixth-floor window and at that position the approximate angle of declination was 15°21’.[C3-331] NUMBER OF SHOTS The consensus among the witnesses at the scene was that three shots were fired.[C3-332] However, some heard only two shots,[C3-333] while others testified that they heard four and perhaps as many as five or six shots.[C3-334] The difficulty of accurate perception of the sound of gunshots required careful scrutiny of all of this testimony regarding the number of shots. The firing of a bullet causes a number of noises: the muzzle blast, caused by the smashing of the hot gases which propel the bullet into the relatively stable air at the gun’s muzzle; the noise of the bullet, caused by the shock wave built up ahead of the bullet’s nose as it travels through the air; and the noise caused by the impact of the bullet on its target.[C3-335] Each noise can be quite sharp and may be perceived as a separate shot. The tall buildings in the area might have further distorted the sound.