Pitch variations heard as a fast wavering or wobbling caused by a software medium (such as an audiotape or CD) moving at varied speeds. As the tape or CD or other media is moved faster, the sound “speeds up” and then it slows down as the media is moved slower. This speed up and then slow down then speed up and slow down causes a variation up and down similar to a butterfly’s wings fluttering up and down. The result is a wobble in the sound (think of speaking into a fan and hearing your voice wobble or flutter up and down as the fan blades spin around).