Amplifier's are a crucial part to any car audio system, they provide the power your speakers demand. To get thumping window rattling bass and crystal clear highs power amplifiers are a must. Amps are the best way to improve your sound quality; in dash mounted receivers and factory amplifiers are just not up to the task. Amplifiers are categorized by class, and channel outputs. Class A/B amplifiers provide high fidelity with low distortion, excellent for SQ or sound quality applications. Class A/B amplifiers are not very efficient, they typically average around 60% input power to output power ratio. Class D amplifiers are more efficient but produce more distortion, typically exceeding 90% input power to output power. Class D amplifiers are perfect for subwoofer applications.