 There is no standardization of how symbols are expressed.Even a sound card that contains high-quality sampled sounds can have inconsistent quality from one sampled instrument to another, while different model cards have no guarantee of consistent sound of the same instrument.Early budget-priced cards, such as the AdLib and the Sound Blaster and its compatibles, used a stripped-down version of Yamaha's frequency modulation synthesis (FM synthesis) technology played back through low-quality digital-to-analog converters.