Do speakers use energy even when nothing is playing?

Question

Lets say its a 2.1 speaker set that has its own power source that is used for computers.

and if it does use up energy, how much when the speakers are "idle"?

Answer 1

Typically, by themselves, speakers do not use any energy when "inactive", or not playing music or sound.

But, in the case of a computer speaker "system" that has built-in amplifiers and power source, it is the "amplifiers" and power supply that are using the power, even when no sound is playing. How much power really depends on the system. But, probably not very much power when idle. Probably anywhere from a few tenths of a watt to a few watts - just depends on the specific system.

Answer 2

That depends on the type of power supply it has.

According to Consumer Reports, a linear (standard transformer-type) AC power supply uses 2 to 5 watts of power just by being plugged in. And most electronic equipment is powered by a linear power supply (as opposed to a switching power supply), because they're cheaper to produce.

A switching power supply uses a transformer, too. But, because it is a much more efficient design than a linear power supply, the transformer required is much smaller and doesn't give up as much heat. A linear power supply is about 30% efficient, which means 70% of the energy used is lost as heat. But, a switching power supply is about 80% efficient.

So, in 2005, the EPA started rating Energy Star power supplies for electronic devices. And, in 2006, the state of California made it mandatory for all electronic equipment sold in the state to have a switching power supply. Nationally, manufacturers have also complied with this regulation, so as not to lose the large California market for electronic equipment.

So, if you bought your speakers before 2006, they are wasting 2 to 5 watts of energy just by being plugged in. But, if you bought them new after 2006, chances are they have a switching power supply and are using less than 1 watt sitting there idle.