The violin can make a wide range of sounds, not all of them sweet. As James Ehnes explains in his latest how-to video, composers call upon violinists to use different techniques to create a variety of colours for special effect. Two such techniques are sul ponticello (over the bridge) and sul tasto (over the fingerboard).
Simply put, sul ponticello produces an eerie sound that's indispensable to the soundtrack of most horror movies. Sul tasto produces a covered, somewhat nasal sound that Ehnes compares to the tone of a clarinet.
Watch Ehnes demonstrate both techniques in the video below: