Wattage Ratings - 2ch vs 5/7ch (1 Viewer)

[Victor Ferguson]

Over the past few months I have been involved in a number of disccussions regarding wattage ratings. I have argued that amoung sub $1000 amps/recievers only a few manufactures (H/K, Outlaw, amoung a few others) use "real" numbers and that most do not (Sony, Pioneer). I have stood by my arguement that a true wattage rating for a home theater reciever should be all channels driven 20hz -20khz. Many have disagreed with my opionion about that and I'm sure many more will. I was flipping through a Sound and Vision magazine last night and saw something interesting...

Note these measurements are at 1Khz and not even 20-20

MARANTZ SR4500 Rated power by manufacture - 80 W x 7 into 8 ohms with maximum 0.08% THD
DOLBY DIGITAL PERFORMANCE: (Output at clipping 1khz 8ohms)
1 Channel - 118 watts
2 Channels - 98 watts
5 Channels - 76 watts
7 Channels - 64 watts

Pioneer VSX-815 Rated power by manufacture - 100 W x 7 into 8 ohms with maximum 1% THD
DOLBY DIGITAL PERFORMANCE: (Output at clipping 1khz 8ohms)
1 Channel - 110 watts
2 Channels - 95 watts
5 Channels - 70 watts
7 Channels - 61 watts

Sony STR-DE698 90 W x 7 into 6 ohms with maximum 0.09% THD
DOLBY DIGITAL PERFORMANCE: (Output at clipping 1khz 8ohms)
1 Channel - 141 watts
2 Channels - 122 watts
5 Channels - 35 watts
7 Channels - 31 watts

With all channels driven not one of the above recievers produced the wattage they claimed with all channels driven at 1khz (not even 20hz-20khz which is how I belive the tests should be).
Another point I would like to make. Some people on the forum have claimed that with all channels driven the manufacures spec will probably be off by 10 watts at most and I have claimed that it would be much more than that. I think the numbers above show why I feel that way.

Here is the link to the Sound and Vision test results:
http://www.soundandvisionmag.com/as...control_lab.pdf

The whole article is on there site to if anyone is interested.
P.S. I have also stated that magazines are not to be trusted as they get advertising dollars and don't give bad reviews. As bad as the Sony did they hardly dogged it all which is sad considering they are selling a 90x7 reciever that puts out 31x7.

 

[John S]

My only point is the fact that it is rare all channels would need to be fully driven, so it is not near as big of a deal as it can and is sometimes made out to be. All of these AVR's would best be served by a higher cross from the sub to the mains. Relieving them of the below 100hz stuff free's up a lot of power.


But your right, you can never have to much headroom. But for an average user/owner all these AVR's would more than likely be fine for them.


Not me, I have become a power freak these days, but I am not the average user, I am demanding on my HT.

 

[ColinM]

That's why I like Stereophool, they have detailed technical sections that often differ with the subjective gushings of the reviewer. They did cables in the last issue, and the tech section called them seriously flawed while the reviewer thought they were fantastic.

Also, about 1/5 of the items are faulty and a second sample tests better - we're talking $1000's of dollars' worth and faulty??

 

[Jack Briggs]

Victor, I too have had the same thoughts as you. Remember the heyday of two-channel stereo? After around 1970 or so, the manufacturers told the truth about their power ratings, usually expressed as X-number of watts at 8 Ohms from 20 Hz to 20 kHz at .XX % THD and IM -- with both channels driven. Also tested by the magazines was the 1 kHz power output at clipping.

Nicely informative, and nearly all manufacturers rated the equipment conservatively.

Yet, with the advent of multichannel home-theater audio, it's back to some of the pre-1970 nonsense, with none of it really telling us anything.

 

[Shiu]

Yet S&V gave the sony DE897 a very decent review.
http://www.soundandvisionmag.com/ass...verlab0804.pdf

1 channel - 149W 8 ohms 227W 4 ohms
2 channels - 118W 8 ohms 181W 4 ohms
5 channels - 76W

I agree manufacturers should clearly spell out their 1,2,5,7 channel output at say

 

[Earl Simpson]

Link above does not work!

 

[Earl Simpson]

Very dated link!
http://www.geocities.com/Area51/Holl...1/ratevsac.htm

 

[James Phung]

I compiled this list of numbers awhile back in another thread from receiver power tests from Home Theater Magazine

Receiver - WPC - 5 Channels Driven at .1% Distortion
Denon 2105 - 90 - 62.4
Marantz 4500 - 80 - 74.4
NAD 753 - 70 - 93.7
Elite 52tx - 110 - 115.3
HK 630 - 75 - 79.7
Denon 3805 - 120 - 114.9
Sherwood 865 - 100 - 71.1
Elite 55txi - 100 - 87.9