In 1974 the Federal Trade Commission (FTC) published a Trade Regulation Rule (TRR)
covering the advertising of power output claims for amplifiers utilized in home entertainment
products. The purpose of the Rule was to establish a common standardized method of amplifier
power output measurement along with the requirement that advertised power output should be
derived from the standardized measurement procedure. Prior to this FTC TRR, different
manufacturers were using methods of power output measurement and advertisement of resulting
power output that caused a certain amount of consumer confusion. The FTC 1974 TRR did not
cover equipment intended for the car because at that time the auto sound business was not of
significant size. The recent rapid growth of car stereo resulted in many of the same practices that
prompted the FTC 1974 TRR. The FTC, however, was not receptive to mending the Rule to
cover equipment intended for the car.