Speaker power ratings vs. aplifier power ratings?


This is probably a stupid question that has been answere here many times but her it goes anyway......

If a speaker is rated at 120 WPC at 4 ohms such as my Green Mountain Europa's how close to that power rating do I have to stay near when choosing an amplifier?

In other words, does 120WPC mean 120WPC with no room for deviation?

group3e11

Showing 1 response by newbee

No. Usually a speaker manufacturer's power rating only means maximum power input for designed performance. Uusually much less power is actually required to get satifactory performance in a typical set up.

This is all kind of loosy-goosy but the simplist was of explaining what is a complex subject is to take the db rating i.e. 86db for 1 watt of power imput and for every 3db of increase in speaker output you double the amp power as such -

86db - 1 Watt
89db - 2 Watts
92db - 4 watts
95db - 8 watts
98db - 16 watts
101db - 32 watts
104db - 64 watts
107db - 128 watts
110db - 256 watts

Assuming your speakers efficiency rating was 86db then the manufacturer would be telling you that his speaker could produce sound pressure levels within a few feet of the
speaker to a maximum limit of 107db without damage to the speakers or the onset of serious driver distortion.

FWIW this is an overly simplistic, but it should give you an idea of whats involved.