THE ALL CHANNELS DRIVEN FALLACY

[PENG]

where do you get ratings like this peng? i cant find any for my rx-v 640 and the rx-v 1500 ; cant find it at htmag btw

"By 2 channel output into 8 ohms at 0.1% THD:
Denon (132.2W), Pioneer (121.2W), Yammie (102.9W), HK (84.6W)"

im only interested in 2 channel output (not this ALL channel stuff)

Buck answered the question for me already, those numbers were for the Denon 3805, Yamaha 2400, HK630.

I cannot find any bench test results for the RX-V1500. The best I can do for you is to repeat what I posted before, there is a "Megatest" done by the WHAT HI*FI sound and vision magazine in November 2004. They picked the RX-V1500 the winner over the NADT773 and the HKAVR630. They did not include any bench test results in their review but here's some of what the reviewers said:

"........It packs a powerful punch, with plenty of solid weight adding emphasis to explosive film sounds. Scenes from Behind Enemy Lines had our review room literally shaking. While some receivers fluster in the face of high-powered spcial effects, the Yamaha keeps a firm grip of low frequencies and maintains its composure throughout. There's also brains to match the brawn, with a midrange that's both realistic and detailed, able to extract emotion from dialogue and, together with subtle and cohesive panning, it enhances the film's atmosphere..............."

In contrast they said this about the HK:

"........The AVR-630 receiver is capable at lower levels, but it's not the most authorative of amps, tending to lose its poise under pressure.........."

Keep in mind the Yammie cost £400 less than the NAD and £200 less than the HK.

Audioholics did publish bench test results for the RX-V2500.

http://www.audioholics.com/productreviews/avhardware/yamaharxv2500benchtestp1.php

The 2CH power output of the 2500 should be very similar to that of the 1500. The results are quite impressive, much improved from the RX-V2400.

It seems to me the RX-V1500/2500 are among the best values in their price range. You should be a happy owner.

 

[mike c]

thank you very much PENG, the 2500 benchtest link was very helpful. i figure i deduct 10+- watts off the 2500 test and i get the 1500 result

its easier to make a decision here because the HK 630's price here is spectacular

 

[PENG]

thank you very much PENG, the 2500 benchtest link was very helpful. i figure i deduct 10+- watts off the 2500 test and i get the 1500 result

its easier to make a decision here because the HK 630's price here is spectacular

You are right if you are in Canada, e.g. C$3299.99 (now on sale for C$3134.99) or US$2,805 for the AVR-7300.

 

[Pyrrho]

Cool, that answers my question. That's sort of what I figured. So in reality this instant current spec really has no bearing on an amplifiers capability in any real world senario. Why do these companies do this to us? The people on this forum are probably some of the most educated in the industry and we're still all confused by it. Thanks for straightening it out.

They do it to sucker you into buying their equipment. They are, after all, in business to make money. So any nonsense that will get you to part with your money is best, as long as they don't go to jail for it, and, if they are smart about long term profitability (many are not), as long as it does not lose future customers.

 

[Pyrrho]

I can't help but to disagree with some member's statements about manufactures being honest about their ratings. Why wouldn't a consumer assume that the power rating was with all channels active? They list stats like 120w X 7 and total wattage number that adds up to sum of each channel if powered on its own. I feel this is misleading. We know the truth because we discuss it, study it, and test it independently. But for the average consumer they would walk away misinformed and without a clear picture of the output of the receiver. When car manufactures post horsepower ratings of their engines, they don't just add up that each individual cylinder will produce. They give the HP of the engine as a whole.

On a side note...this is the reason I decided to purchase a HK receiver. If they are honest (and I feel they are where others are not) about their power ratings, then I have more confidence in the other elements of the receiver.

HK is as misleading as most. Their claims of "high current" are so much marketing BS.

 

[Buckeyefan 1]

This is why advertisers get away with these multi-channel ratings:

http://www.ftc.gov/opa/2000/12/amprule.htm

Specifically:

The Commission subsequently issued in the July 19, 1999 Federal Register a Notice of Proposed Rulemaking (NPR) that solicited public comment on specific proposed amendments to the Rule to:

reduce the power output requirement during the one-hour preconditioning period from one-third of rated output to one-eighth of rated output, and grant testers of self-powered subwoofers the discretion to choose the frequency of the test signal to be used during the preconditioning period;

exempt advertising disseminated through the media from disclosure of total rated harmonic distortion and the associated power bandwidth and impedance ratings when a power output claim is made; and

allow the subwoofer and satellite amplifier sections in combination self-powered speaker systems to be driven to full rated power separately, rather than simultaneously, during the power rating tests.

 

[mtrycrafts]

This is why advertisers get away with these multi-channel ratings:

http://www.ftc.gov/opa/2000/12/amprule.htm
. [/I]

Why is it 'getting away' with something?

Before the advent of amps with more than 2 channels, FTC set standards after a 'wild west days' in audio advertising.

Since the advent of multi channel amps, the need is different. FTC examined the issues and made a new rule. So, why do you think someone is getting away with something???

Perhaps it is not how you would do it, obviously, but that is not 'getting away' with something.

Perhaps HK is getting away with something more sinister with their 'high current' claims.

Maybe you can protest FTC and one day, they will see it your way?

By the way, I am just noticing two boxes in the upper right corner on this reply message:
close current tag
close all tags

Is this new? What is it?

 

[jaxvon]

Re: Tag closing

That's always been there, it's just a feature to close all PHP tags that you have going like the bold, italic, quote, url, etc.

 

[mtrycrafts]

Re: Tag closing

That's always been there, it's just a feature to close all PHP tags that you have going like the bold, italic, quote, url, etc.

Jeeze your'e fast
Thanks. Never noticed it, or just blocked it from memory.
Like in new audio gear, 'I never heard that from the old components'

 

[T-Bone]

While bench tests results for watts into 8 Ohm loads are valid, watts into 4 Ohm loads are usually not because most receivers cannot handle a 4 ohm load at loud volumes for a long period of time.

The denon and yammy quoted here are not to be used with 4 Ohm loads since they are spec'd for 6 and 8 Ohm loads only. I believe the HK is suitable for 4 Ohm loads... so while the HK rates lower than the others w.r.t. 2-ch and 5-channel all channels driven, it'll handle 4 Ohm loads over the long haul while the others will distort.

-T

 

[gene]

The denon and yammy quoted here are not to be used with 4 Ohm loads since they are spec'd for 6 and 8 Ohm loads only. I believe the HK is suitable for 4 Ohm loads... so while the HK rates lower than the others w.r.t. 2-ch and 5-channel all channels driven, it'll handle 4 Ohm loads over the long haul while the others will distort.

While I understand that is your belief, it is unfortunately untrue. The similar priced HK receivers are no more capable at driving 4 ohm speakers than Denon or Yamaha models. That being said, we have shown good results on mid-priced Yamaha and Denon receivers driving 4-ohm speakers of reasonable efficiency.

 

[T-Bone]

Geez... I hate posting incorrect data. I could have sworn the HK listed 4 Ohm in the manual... turns out that I was wrong. The DPR2005 states it capable to drive 4 Ohm speakers via a 4Ohm/8Ohm switch on the rear panel.

-T

 

[gene]

T;

If I had a dime for every mistake I have made, I have been able to retire before I became a teenager

Just realize that at price constraints of many of these receivers, heat sink area, power devices and power supplies are at a premium and design compromises are almost a certainty. In order to meet UL requirements while driving 4 ohms, many of these products must be tested in at a limited max unclipped power rating, hence the 4 ohm switch. In most cases, with todays moderately efficient home theater speakers, 4 ohm loads usually won't present a problem, especially when bass management is applied to them.

 

[aarond]

Lets see what thee FCC has to say
FCC regulations
Part 432-Power output claims for amplifiers utilized in home entertainment products

432.2 (a) Whenever any direct or indirect representation is made of the power output, power band or power frequency response, or distortion characteristics of sound power amplification equipment, the following disclosure shall be made clearly, conspicuously, and more prominently than any other representations or diclosures permitted under this part: the manufacturer's rated minimum sine wave continuous average power output, in watts, per channel (if the equipment is designed to amplify two or more channels simultaneously) at an impedance of 8 ohms, or, if the amplifier is not designed for an 8 ohm impedance,at the impedance for which the amplifier is primarily designed, measured with all associated channels fully driven to rated per channel power
(bold added for emphasis), word for word from FCC)
So where is the fallacy in all channels driven?
It appears to be required by the FCC

Aaron

 

[Buckeyefan 1]

Aaron,

That's only if the amp is not designed for an 8 ohm impedance.

The restriction with amps designed for 8 ohm impedences are per channel, meaning one channel (all manufacturers rate power at 2 channels since their amps are manufactured to run at least two channels simultaneously).

Every amp we discuss here is designed for 8 ohm impedences. Some will handle 4 ohm, but there's always an 8 ohm rating.

 

[aarond]

Aaron,

That's only if the amp is not designed for an 8 ohm impedance.

The restriction with amps designed for 8 ohm impedences are per channel, meaning one channel (all manufacturers rate power at 2 channels since their amps are manufactured to run at least two channels simultaneously).

Every amp we discuss here is designed for 8 ohm impedences. Some will handle 4 ohm, but there's always an 8 ohm rating.

The 2 channel ratings come from the old stereo regs. With the new home entertainment regs its 5,6 or 7
What does "measured with all associated channels fully driven to rated per channel power" mean? 2 channels? I think not!
The reason they rate with 2 channels driven is because that's how they have always done it. If nobody complains to the FCC then they will keep doing it even with new requirements in place.

There is not always an 8 ohm rating most panasonics are rated at 6 ohms and the bottom of the onkyo line are rated at 6 ohms

 

[Buckeyefan 1]

You need to read between the lines.

if the amplifier is not designed for an 8 ohm impedance

Panasonic and low end Onkyo's, although rated at 6 ohms, are also designed to run an 8 ohm impedance. Panasonic and Onkyo never say they are primarily designing amps to run 6 ohm loads. They state this to reach certain wattage figures to sell units (just as they increase thd figures to almost audible levels). These ratings are based on 2 channel bench tests, and not multiple channels.

No doubt about it - the FTC needs to revamp their system. Clearly people are buying for the wrong reasons. This is especially true in big box stores who sell lower end units, as well as 990 watt HTIB systems.

 

[aarond]

Disregard the 6ohm 8 ohm language in the regs. That was rallied for by manufactures to side step the regs.

The fact of the matter remains, with the new regs the amplifiers are supposed to be measured with ALL associated channels driven to rated per channel power.
These are the requirements for amplifiers utilized in home entertainment products.
The manufacturers will continue to rate with the old regs untill people start complaining to the FCC.

 

[gene]

So where is the fallacy in all channels driven?
It appears to be required by the FCC

First off its an FTC NOT FCC PROPOSAL NOT A RULING.

Did you even bother to read it? This PROPOSAL deals mostly with sub/sat systems and computer speakers and how they should be rated.

http://www.ftc.gov/os/1998/07/63FR37237.pdf

If you don't see why the ALL CHANNELS DRIVEN test is a fallacy for multi channel receivers and power amps after reading all of the posts in this thread, than I am not sure I can help other than to restate a few key points such as:

1) This is NOT a real world test condition. Music isn't a continuous sine wave with ALL CHANNELS DRIVEN.
2) It isn't even achievable continuously for most dedicated amps let alone receivers which utilize linear amp designs and a single power cord.
3) Most magazines test using a VARIAC to hold the line voltage up, thus exceeding the typical 15A circuit to achieve these inflated #'s
4) Most magazines use an AP sweep tone which isn't a continuous RMS test and represents more of a max instantaneous power rating

 

[Audioholics]

We're really not interested in arguing this point further. What we're about is educating the public - one that is apparently willing to be led around by the nose with bogus test procedures and impractical power ratings.

Now, a few select people keep doing everything they can to steer people away from the truth and back towards the all-channels-driven nonsense. Unfortunately, these people apparently have trouble reading, let alone understanding the concepts behind these tests, so their information is a bit skewed. This forces us to continually intervene and re-hash the same things we've said all along.

Please do not make our jobs more difficult. We're not wrong on this and we have more important things to do than argue this topic ad infinitum. It's not as if some company is paying us to debunk all-channels-driven. It is a significantly flawed test and we are working up much better solutions to compare products in more real-world scenarios.

For those interested, the FTC is in process of developing multi-channel test procedures that are more representative of real world scenarios. Stay tuned.