Audio Power

For us regular people the topic of stereo wattage, speaker wattage, and Audio Power can be a bit confusing. Chances are you’ll only want understand the basics about audio power (article on electricity and what is watts), stereo amplifiers and speaker wattage to help you in properly matching stereo equipment you already own or buying the right stereo equipment.

Stereo sound, or audio power, as it relates to people on a whole can be dissected into three pretty basic categories:

1)  Those who don’t care about audio power but just want to plug in some music and listen to it in the background. Boom boxes, stand-alone radios or speakers work best for this scenario. Chances are they aren’t researching topic.
2)  Then there are those who absolutely love high-fidelity audio and care a lot about audio power and are looking for the very best matched receivers, amps, wiring, speakers, acoustical room treatments etc. This article isn’t necessary geared to these folks. This category would typically require investing time in a professional listening room before deciding on the best match of equipment and installation.
3)  And then there’s everyone else, those who might not be overly concerned with audio power but rather want a nice audio system and want to be careful on spending their money on the right equipment. They want to know what they are buying is appropriate for not only the money they are spending but their tastes in sound. Usually they want nice background music or other audio and sometimes they want to turn it up for a party, movie for sporting event. It generally takes fewer watts then you might think to accomplish these things.

A speaker more often than not will have a wattage rating label. For example a typical speaker might be rated to handle up to 100 watts. Therefore anything over 100 watts will distort the sound and likely permanently damage the speaker.

What powers the speaker so that audio sound can be heard is an amplifier. Amplifiers can be standalone amplifiers which require an audio source like a CD player connected to the amp. Or, an amplifier can be built into what’s commonly known as a stereo receiver or even more advanced Surround Sound receivers. In any case… these amplifiers, like the speaker, also have a wattage rating labeled on the backside of the unit. For Example, the rating for the amplifier might be listed as 100 watts per channel or another amplifier might be labeled as 600 watts total output. A channel, typically, equates to one speaker; in other words a single speaker is connected to a single channel on the amplifier. Therefore, in the case of the 600 watts total output amplifier it would output 100 watts per speaker to 6 different speakers…hence 6 X 100 =600 watts total output.

How many watts of Audio Power do you need?

To hear audio… this question needs to be answered a certain way. Just because an amplifier is rated at 100 watts output doesn’t mean the amplifier, when turned on, is always outputting the full 100 watts. The wattage output increases as you turn the volume up but here’s the interesting part, if you want to double the volume it requires more than double the watts.

As volume increases the wattage required from the amplifier increases at higher rate; it’s not a straight line relationship. For Example: a volume set on the amplifier at 20% might require 15 watts whereas a volume set at 40% might require 45 watts. 

For background music, setting the audio power volume at 20% could be just about right if not a bit too loud. 40% would be for a household party or movie and might be considered rather loud, borderline unpleasant.

Audio Power – In Summary

Considering your tastes, objective, and budget, a speaker should be at least 20% more capable then the amplifier’s peak output. You’ll seldom if ever listen at that highest volume and on the flip side you generally won’t ever risk damaging your equipment at those peak volumes either.

There are other considerations to account versus just audio power are, such as, ohms when matching speakers but a general rule of thumb on ohms would be if the amplifier support an 8 ohm speaker then you need an 8 ohm speaker (not a 4 ohm or 6 ohm speaker) for that given amplifier. This data too is typically imprinted on ratings stickers.