What are the way's receivers can be power rated?

[Canada]

I only know of one.

All channels driven which I belive is the best way to rate watts.

But why amd what are the other reasons of rating watts from a receiver or amps.

[HiDefRev]

There are basically as many ways to rate power as there are stars in the sky. 1 channel driven, 2 channels driven, etc. Then there are different levels of Total Harmonic Distortion for each of the above - 10%, 1%, 0.1%, etc., etc. Then there is the PMPO method ( Peak Momentary Power Output - NEVER trust this method ) that measures a very short burst of power, as opposed to continuous power. Then there is the method of using different amounts of resistance ( 8 ohm, 4 ohm, etc. ) And I am sure that I have probably left something out. The most reliable would be - " X watts continuous, with all channels driven at less than 0.1% THD, into 8 0hms ( or 4 ohms, if that is the resistance of your speakers )". But, some manufacturers like to fudge the figures as much as they can.........

[Fors*]

I agree with HiDefRev, as a lot of times the rating you see or quoted are only with one or two channels driven. Quite often, people overlook this fact, thinking they are getting all 140 watts for each channel, when pushing all 7. Since there is no "standard", this all becomes how to market the receiver, unfortunately.

[richteer]

Originally Posted by forsberg21

I agree with HiDefRev, as a lot of times the rating you see or quoted are only with one or two channels driven. Quite often, people overlook this fact, thinking they are getting all 140 watts for each channel, when pushing all 7. Since there is no "standard", this all becomes how to market the receiver, unfortunately.

On this side of the Atlantic anyways. When I lived in the UK (10 years ago now!), consumer law stated that amplifier ratings must be in RMS WPC into 8 Ohms, both channels driven (ratings into other loads may also be given). In these days of multichanel amps, I would imagine that the definition has been modified to "all channels driven".

[Steve]

Originally Posted by richteer

On this side of the Atlantic anyways. When I lived in the UK (10 years ago now!), consumer law stated that amplifier ratings must be in RMS WPC into 8 Ohms, both channels driven (ratings into other loads may also be given). In these days of multichanel amps, I would imagine that the definition has been modified to "all channels driven".

I would love to see such a requirement here as it would make it much easier to compare different receivers/amps by the specs alone.

[rded]

Originally Posted by richteer

On this side of the Atlantic anyways. When I lived in the UK (10 years ago now!), consumer law stated that amplifier ratings must be in RMS WPC into 8 Ohms, both channels driven (ratings into other loads may also be given). In these days of multichanel amps, I would imagine that the definition has been modified to "all channels driven".

Oh so true Rich! I wish this would be a universal consumer law. Besides,(you and I both know this all too well)- POWER ISN'T EVERYTHING!

[richteer]

Originally Posted by fireman325

I would love to see such a requirement here as it would make it much easier to compare different receivers/amps by the specs alone.

Agreed, although I should point out that an amplifier's power rating is absolutely no indication of its sound quality, and that's really the only parameter that matters!