How powerful does my AVR need to be?

My question is - what kind of power rating should I be looking for in order to push a constant 100W to my 6ohm fronts (5.1 setup)?

You say it probably won't tax any AVR - even a budget receiver like the Denon AVR-1612?

Originally Posted by blakeyj08

So I've read through the stickied posts and searched for others, but basically what I've been able to take away is that every brand rates their watts/channel differently, and unless it's HK you don't know what you're getting.

My question is - what kind of power rating should I be looking for in order to push a constant 100W to my 6ohm fronts (5.1 setup)? Is it possible to get an AVR that will do it for <$500?

I keep looking at receivers advertising 100W+/channel, but then it always turns out that's with 2 channels driven, and it drops to around 80W/channel with all driven.

Thanks for any help

Originally Posted by commsysman

Unless you hear distortion on peaks, you don't have a problem.

Originally Posted by blakeyj08

So I've read through the stickied posts and searched for others, but basically what I've been able to take away is that every brand rates their watts/channel differently, and unless it's HK you don't know what you're getting.

My question is - what kind of power rating should I be looking for in order to push a constant 100W to my 6ohm fronts (5.1 setup)?

Is it possible to get an AVR that will do it for <$500?

I keep looking at receivers advertising 100W+/channel, but then it always turns out that's with 2 channels driven, and it drops to around 80W/channel with all driven.

Originally Posted by arnyk


That seems narrow and harsh. In the US there are laws related to how power ratings are determined, and they are often overkill.

Where does this 100 wpc criteria come from?

Yes.

So what? 80 watts is only 2 dB less than 100 watts, and it takes a whopping 10 dB of power difference to create the impression of just twice as loud.

Have you ever heard an actual 2 dB difference in power being delivered to a speaker? Remember that over just a few seconds the power being delivered to a speaker can change as much as 60 dB or more.

The hidden gotcha is that music is far easier to amplify than steady tones. because it has a constantly varying amplitude. Power supplies, heat sinks and output transistors are far more stressed by the steady grind of a sine wave.

Music is also constantly varying in terms of frequency content which means that the effective impedance of your speakers is also constantly varying because their impedance is frequency dependent. While your speakers may be rated at 6 ohms, their effective load on the amplifier is probably significantly lower with real world music as compared to the sine waves used in power ratings.

The power supply and heat sinks in even very low cost receivers is usually overkill because advertised ratings have to be based on sine waves while music is what we usually listen to.

100W in 5.1 usually means 200W in stereo.

Originally Posted by mcnarus

Usually? Have you got some basis for this statement? I don't know that it's wrong, but IME power specs are all over the map. Drawing any conclusion about them is dangerous.

I got it from whatever test data I saw. "Usually" means exactly that - in most cases, with few exceptions.

Just drawing from some published test data, the claim that "100W into 5.1 equals 200W into stereo" is likely false. I'm not pretending to speak for all equipment, but there's a lot of equipment that absolutely does not live up to that burden.

Originally Posted by mcnarus

Thanks for the links. 2:1 seemed rather high to me, and your examples suggest that 1.5:1 might be more in the ballpark. But this is assuming you're dealing with honest, consistent measurements. When it comes to spec sheets for AVRs, you can assume no such thing. The FTC rules might as well not exist anymore.