What does this spec mean?

[z24lucifer]

I just picked up the htr-6080. I found one of the specs pretty confusing:

RMS Output Power (20Hz - 20kHz) 105W x 7
RMS Output Power (1kHz) 120W x 7

Can somebody please explain to me what this means?

Thanks again!

[Beta Man]

RMS (someone correct me if I'm wrong) is a list of the "sustained" power output if you will... rather than the "peak" at which it can hit. For instance, some subwoofers are 500 watts, but really only 200 watts RMS.

It's more important than "peak" power.....

[desmond]

http://en.wikipedia.org/wiki/Audio_power

[richteer]

Originally Posted by z24lucifer

I just picked up the htr-6080. I found one of the specs pretty confusing:

RMS Output Power (20Hz - 20kHz) 105W x 7
RMS Output Power (1kHz) 120W x 7

Can somebody please explain to me what this means?

Thanks again!

RMS (Root Mean Squared) is the only "proper" power output. Peak power is just a con; conversely RMS is the sustained output capability into a given load at a certain frequency (usually 8 Ohms at 1 KHz). So what those specs are claiming is at 1KHz, the amp will deliver 120W across all 7 channels (probably assuming the use of 8 Ohmo speakers).

What the first figure indicates is that the amp can't sustain that output across the full frequency range, probably due to a crappy (i.e., insufficient) power supply.

[Beta Man]

Originally Posted by richteer

RMS (Root Mean Squared) is the only "proper" power output. Peak power is just a con; conversely RMS is the sustained output capability into a given load at a certain frequency (usually 8 Ohms at 1 KHz). So what those specs are claiming is at 1KHz, the amp will deliver 120W across all 7 channels (probably assuming the use of 8 Ohmo speakers).

What the first figure indicates is that the amp can't sustain that output across the full frequency range, probably due to a crappy (i.e., insufficient) power supply.

[desmond]

Originally Posted by richteer

RMS (Root Mean Squared) is the only "proper" power output. Peak power is just a con; conversely RMS is the sustained output capability into a given load at a certain frequency (usually 8 Ohms at 1 KHz). So what those specs are claiming is at 1KHz, the amp will deliver 120W across all 7 channels (probably assuming the use of 8 Ohmo speakers).

What the first figure indicates is that the amp can't sustain that output across the full frequency range, probably due to a crappy (i.e., insufficient) power supply.

True but loss of power is almost certainly at low frequencies so if you are using a sub it won't be a big issue.

[z24lucifer]

I should have clarified, I know what RMS power is, but I wasn't sure why the power is different between 1kHz and to 20Hz - 20kHz.

Does that mean that it puts out more power on higher notes and less on lower?

[musicman1999]

In the real world the only way those ratings would have any meaning would be if they were followed by the words "with all channels driven". Most inexpensive receivers test their amps with only one channel running not all channels and they do not have to make that distinction. That allows them to advertise 105watts per when in reality they might put out 50 or 60 with all running.

bill

[richteer]

Originally Posted by z24lucifer

I should have clarified, I know what RMS power is, but I wasn't sure why the power is different between 1kHz and to 20Hz - 20kHz.

Does that mean that it puts out more power on higher notes and less on lower?

It means that the amp can't delivery its full power across the whole audio range. It might provide less power in the lows, or less on the highs; one can't say just by looking at the spec. But as another poster speculated, the tail off is probably at the low end.

[chasarms]

Originally Posted by richteer

. . . What the first figure indicates is that the amp can't sustain that output across the full frequency range, probably due to a crappy (i.e., insufficient) power supply.

The impedance of a load changes with frequency. Because output is directly related to impedance, the output changes as the frequency changes.

It is not necessarily a matter of less output at lower frequencies. The impedence of a loudspeaker is most accurately represented by a x-y graph. The peak is inherent to the design of the speaker.

That said, the 105 RMS is the most significant spec. However, difference between 105W and 120W RMS would not be significant in the real world.

[Krayge2469]

also remember, RMS tends to be a measure of constant power. In 12-volt audio, RMS is a very important factor since you have a constant output going to your subs, tweets and everything in between. with home audio, your audio is gonna be interspersed with periods of no sound or very low sound as well. RMS doesn't factor in quite as highly due to the lack of a "need" for constant power feed. Thus, in home audio RMS is a factor to look at, but it's not the end-all of performance to look at. look more for frequency range, signal-to-noise ratio and put RMS somewhere after those