Speakers do not have a "watt output". Speakers are rated in terms of the minimum, continuous, and maximum power they can handle, which is expressed in terms of watts (W). The loudness of a speaker is a function of the power input to the speaker from the amplifier and the speaker efficiency. More efficient speakers require less power to reach the same apparent loudness than those that are less efficient. The apparent loudness of a speaker does not have a linear relationship to the power - the relationship is logarithmic: dB value = 10 * log( Power / RefPower ) The human ear can perceive changes of less than 3 dB in volume. An increase of 1.5 dB is barely audible, but requires a power increase of about 41% (e.g., 100 W to 141 W). A 3 dB increase in volume is audible to anyone with normal hearing and requires twice the power (e.g., 100 W to 200 W). This is why there is really no audible difference between, for example, a 90 W amplifier and a 100 W amplifier. The difference in power is less than 0.5 dB, which is inaudible. Increasing the volume of a speaker until it sounds twice as loud requires ten times the power - an increase of 10 dB. Hence, increasing the power output of an amplifier from 1 W to 10 W (+10 dB) doubles the apparent volume. Doubling it again, to a level four times the original volume (+20 dB), requires 100 W. Without knowing the efficiency of a speaker, it is impossible to determine what power is needed to reach a particular volume level. A 3 dB increase in speaker efficiency has the same effect as doubling the amplifier power, while an increase of 10 dB is equivalent to increasing the amplifier power by a factor of 10. Suffice it to say that most of a person's listening time is spent while the amplifier is producing well under 1 W.