SVM is one of the many tricks manufacturers use to get more light out of a picture tube, at the cost of real picture detail. It changes the speed or velocity of the beam as it is scanned from the left to the right side of the picture. In the process, it distorts real picture detail, causing dark areas of the picture on light backgrounds to be reproduced much larger than normal and light areas on dark backgrounds to be reproduced much smaller than normal. When the beam spends more time “writing” light areas, the phosphors receive more energy and produce more light output. The fact that this will contribute to phosphor blooming, as well as detail distortion seems to be lost on a number of manufacturers calling it a “feature.” The presence or absence of SVM can be easily detected by displaying the needle pulse test pattern. In the test pattern, the width of the white line on the black background, and black line on the white background are the same. In a set with SVM, the width of the black line will be much larger than the white line. If SVM is found on a set, look for an ability to turn it off. Several sets provide this option in the mode of the set designed to accurately reproduce the signal source. In some other sets, it is easily defeated by a qualified service technician.