Wattage specs


HT n00b
Unregistered guest
When evaluating the specs of a receiver, it's a given that some brands "distort" the truth about how many watts each channel is receiving.

My quesiton for this board is if there is a concensus as to which brands are guilty of this distortion and which aren't.

Also, is there any way of finding out for myself?

I own a Yamaha HTR5670, which is specified as 7.1, with 95 watts per channel. What i really want to know is how accurate is that 95 watts. Would there be a huge difference bettween 2 channel stereo, 5 channel stereo and 7 channel stereo?

I'm trying to weigh the pro's (more speakers, more surround sound effect) and con's (less wattage allocated to my mains) of using 0, 1 or 2 rear channels.

Thanks for helping out someone new to the home audio world. Any response will help. :D


Bronze Member
Username: Mike_6289

Post Number: 12
Registered: Feb-05
You should read the manual about that. At one point a friend of mine bought a mini-system that was rated at 300 watts total power. He invited me over, dissapointed about it. I looked in the manual and it said 30 watts per side at 0.8% distortion (really bad) and 150 a side for 10 milliseconds at 10% distortion. Whenever it is tured up to high levels and there is a "peak" in the playback, it turns off!

There was some law passed in the 70s on home audio components. They have to post the continuous output now, though that is still not true for computer speakers or car audio. You see car audio amps rated at 45 watts into 4 ohms when car batteries are only 12 volts! 12 volts into 4 ohms is 3 amps. 12 volts and 3 amps make 36 watts. :-(

Yamaha is a good name and probably would not lie about the output power. The receiver would be 95 watts per channel in 7.1 and still be 95 watts per channel in 5.1 mode. The receiver would probably be able to handle peaks better in stereo mode because it is only driving two channels and the power supply would be directed at those two channels only.

hope this helped

HT n00b
Unregistered guest
Michael, thank you for your reply.

I've checked the manual and it say's
"Minimum RMS output power (0.06% THD, 20Hz-20kHz, 8 omhm)
Front: 95W + 95W
Center: 95W
Surround: 95W + 95W
Surround Back: 95W + 95W"

Can someone explain what the 0.06% THD means?

Gold Member
Username: Myrantz

Post Number: 1383
Registered: Aug-04
Yamaha is well known to have lied about their specs. It is common knowledge. But they are not alone.

I may be wrong but I doubt the Yamaha HTR5670 actually rates at 95W with all channels driven also. Many receivers do not reach their rated output with all channels driven at once - seperately maybe. Most brands are becoming more honest about these ratings in more recent times. The SR-7200 could only manage about 27W ACD and that was a 100+W rated receiver. The SR-7300 does much better as do the latest models (Marantz now guarantees at least 70% of the advertised output with all channels driven ). Nad receivers are known to meet if not better their advertised specs as are some others.

There is a thread here somewhere with a link to a webpage displaying the results of tested receivers with all channels driven. Someone may recall where and offer the link.

THD - Total Harmonic Distortion.

Silver Member
Username: Riches1

Atlanta, GA US

Post Number: 162
Registered: Apr-04
One of my favorite subjects.

Most power ratings are meaningless. Power ratings that read " 70 watts continous, all channels driven, at 20Hz to 20KHz" never happens in the real world. Those power measurements are done generating a test tone and measured against a non-inductive resistor. They are never made while playing music and measured at the speaker. A 20Hz to 20KHz test tone is white noise, not music or audio track.

What happens in a real world setting, are musical peaks and rapid millisecond bursts. Most well regarded 100WPC recievers (Denon, Yamaha -especially the RX-V's, H/K, NAD, Marantz, Pioneer and even Onkyo will be able to handle anything that the typical home theater throws at them.

Some inefficient 4 ohm speakers or electrostatics may be the exception, in which case they should probably be driven by a separate amplifier anyway.

I'll answer the typical rebuttals to this argument in advance. I have heard the argument that the all channels driven is the "only true way" to measure power.

That mantra seems to give NAD and H/K evangelists an air of superiority and makes them feel all warm and fuzzy about the amount of their "power". I seldom see them boast about their THD or S/N ratings. There is no industry standard on measureing receiver power

Someone will drag out the Finnish Hi-Fi magazine report that claims Onkyo 701 only put out 27 wpc - that's just ridiculous.

Read the article about the "All Channels Driven Controversy" at audioholics.com.

Yes the Yamaha HTR's are probably exaggerating the power specs. But I wouldn't lose any sleep over it. Nobody has been "lied to". It's just a difference of measuring techique.

I have owned 1 Pioneer,2 Harman/Kardons, 1 Kenwood, 2 Yamahas, and 3 Denon Recievers. I never found one that couldn't handle the load. Their rated watts per channel ran 55wpc to 120wpc. Not a whole lot of difference in actual output. What??? You may ask.

Well, consider that it takes about 10 watts additional power to increase the sound level by 1dB. The smallest change in volume detectable by the human ear is 3 - 3.5 dB. So it would take at least 30 watts to even produce an audible change in volume. It would take considerably more to produce a "significant change".

That's just my opinion, I could be wrong.....

Bronze Member
Username: Shokhead

Lakewood, CA USA

Post Number: 55
Registered: Jan-05
Yamaha can double talk with the rest of them. Have to look past the watts anyway.

Bronze Member
Username: Sause

Post Number: 31
Registered: Oct-04
With Yamaha the HTR and RX-V series have the same amps in them read Yamaha's web site. That only difference is the face plate. The HTR's are sold in major stores and the internet the RX-V's are not. The differnce in the spec is that the HTR are rate when going at 1K hz while the RX-V is 20-20k.

New member
Username: Thinker311

Post Number: 9
Registered: Feb-05
Is this first statment correct

If you have two recievers one with 100 rms watts and the other 50 watts rms and you turn both their volumes up half way, the 100 watt system is only " ever so slightly" louder than the previous. Then the only advantage the 100 watt system would have is that it produced the sound incredibly better than the 50 watt at that same volume.

Is this second statement correct.

The optimal speaker/reciever match would be the following....for a receiver rated 100 watts rms per channel get speakers that do 50 watts rms at 100 wat max......or......a receiver rated 50 watts rms per channel get speakers that do 25-30 wats rms.

What would happen if u had a reciever that did 50 rms per channel, but had speakers that also did 50 rms.

Any insite will be appreciated.

Bronze Member
Username: Tevo

Chicago, IL USA

Post Number: 22
Registered: Feb-05
Neither one of those statements is correct.

Wattage is not the sole arbiter of the sonic quality of a given component. There are so many other factors which, in sum, can make or break the sound quality. If having the most accurate reproduction of music/sound was solely dependent on wattage... hi-fidelity would be a cakewalk. :-)
And all those folks on single digit wattage s.e.t.'s are out of their minds (j/k).

Here, these articles may provide more insight:


http://www.audioholics.com/techtips/audioprinciples/amplifiers/basicamplifiermea surements.php

Bronze Member
Username: Thinker311

Post Number: 11
Registered: Feb-05
Thanks for posting. I definetly understand where u are coming from. This is a concept that i am trying to grasp. I will admit the first examples i gave were quite horrible. BUT I BELIEVE that the theory i am thinking of is correct. NOT THAT U ARE WRONG, just that there is a missunderstanding as to what i want to know....Let me PLEASE try one last time. So, once again are these statments true......

1. In order to make sound twice as loud you need to add 10 dB to it.

2. Ten times the power is needed to make the sound twice as loud.

3. So, if u wanted a receiver that was twice as loud than a 50 watt, you would need a reciever of 500 watts.

4. So, a 100 watt reciever is only sightly (3dB) louder than a 50 watt.

Please try to work with me here. I DEFINETLY accept critisim. It helps me learn. However, i am not at the pont of knowing all factors yet. Im sure that i've left things out.But i really think that im on to something.

I will now check out those links while i wait for more imput.


Bronze Member
Username: Shokhead

Lakewood, CA USA

Post Number: 56
Registered: Jan-05
#4 is correct. 3db can be more then you think.

Bronze Member
Username: Tevo

Chicago, IL USA

Post Number: 24
Registered: Feb-05
This may help you:


Also, I recommend "The Complete Guide to High-End Audio", 3rd Edition by Robert Harley. This text is the bestcomprehensive text for a budding audiophile.


The better receivers and amps deliver a clean sound that remains cleaner as the volume is turned up. I have seen people who have bought 200 watt amps and been disappointed with the loudness level because the cheaper stuff sounds louder due to the fact that the sound is not as clean. Also there are differences in the way volume controls are made, some or at least in the past some of the volumes used to give all the useable volume increase within half of the movement available while others used all the available movement in smaller increments so it seems like the latter is not as loud to some peoples way of thinking. Probably did not explain that well but hopefully made my point.

Bronze Member
Username: Shokhead

Lakewood, CA USA

Post Number: 57
Registered: Jan-05
You said it right. A good 50watt reciever is better then a cheap 100watt reciever.

Bronze Member
Username: Thinker311

Post Number: 13
Registered: Feb-05
Thanx to all of u, however i have my thought on two diff threads, if want to continue with insight, i will only be in the " 100 watt reciever not loud..."

so thanx to all who replied here

Much like 25 watts per side from a class a amp VS 250 watts a side from say a high end receiver ( not realistic numbers in a reciever) the class a watts will not only sound louder their clarity will be lightyears better in comparison!

Just my 2 cents!

By the way, this forum rocks, class A style!
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