Has the FTC Failed Consumer Audio Regarding Amplifier Power Claims?

[gene]

The Federal Trade Commission (FTC) purpose is to investigate and prevent deceptive trade practices. In 1974, the FTC instituted its Amplifier Rule to combat the unrealistic power claims made by many hi-fi amplifier manufacturers. However, we've noticed a trend of grossly inflated power ratings lately with many Atmos AV receivers and Class D amplifiers. Has the FTC become too complacent with validating and enforcing amplifier power claims since their efforts to rule on multi-channel power amplifiers ceased over a decade ago? And, are manufacturers taking advantage of this?

Read: Has the FTC Failed Consumer Audio Regarding Amplifier Power Claims?

 

[Bookmark]

All companies by nature, bend and on occasion break the rules. Back in the Victorian era it became necessary to regulate ice cream because of unscrupulous vendors adding "extras" to the mix items such as saw dust. The dust maybe gone but we still seeing skating around the definition of "cream" 150 years later.

I think there is a general consensus that if it costs more, then they are more inclined to be truthful. Additionally certain brands cultivate a more open approach to their testing and definitions and farm out the process to reputable 3rd parties and sites like this.

As a general rule myself, I take the quoted channel figure, multiply by channel count and compare with the power usage. If they claim 100w per channel on a 7.1 Amp/Avr and have power draw of 450w then I know it won't get to 100w per channel anytime soon. Does not mean it is useless or bad, just that raises an alert.

I believe if you have a muli channel Amp/Avr then it had better be able to drive all the channels to the rated power, not just a couple or worse just one. The type of amp section A, AB,D, G etc does not circumvent the laws of physics, just the effecincy at how the reach their target.

The comment in the article about 1/3rd power being the worst for AB Amps is a good point and if it fails because of heat then it should be seen to fail. No Amp/Avr is use at 100%, 100% of the time. If its prone to fail due to poor heat management then the manufacturer should be forced to redesign.

The phrase "Buyer beware" should always be considered with a purchase. You could introduce a raft of regulations and standards, but in the end, if it has any loophole it will be exploited. Just look at MPG in cars and the VW emissions scandal.

Safety however is paramount and there should be no fudge here, padding the output figure I can live with.

 

[JohnBooty]

There's clearly a point at which government regulation becomes counterproductive and harmful. Maybe I'm just ignorant but I've certainly never heard of any great stereo gear being produced inside 1960s Soviet Russia.

However, this article an excellent illustration of what happens when there's too little government intervention.

It's not practical for consumers to become fully educated experts on every product they might buy in their lifetimes. Amplifier power ratings (and their relationship to the sound one actually hears in one's home) are poorly understood even by many dedicated hobbyists, and in the absence of a reliable power rating specification manufacturers are able to tell outrageous lies to customers. The result is bad for consumers: why should companies bother to produce better goods, when they can simply lie to consumers who aren't equipped to understand the murky technical depths of these fake numbers?

Then again, maybe this is an argument for the private sector after all.

Why? Even when strictly adhered to, the FTC power rating specification kind of sucks.

• It's easy to cheat. There are no restrictions on THD, so you can specify your amp's output at a nasty 10% THD.
• The importance of the numbers themselves, even when honest, are counterintuive: how many consumers realize that a 100wpc amp is only slightly (3dB) louder than a 50wpc amp?
  
• How many consumers realize music is highly dynamic, which means that a system's ability to handle peaks is more important than its ability to play pink noise?
  
• How many consumers realize their speakers' sensitivity generally has far more effect on your system's output levels than your amplifier? In terms of SPL, moving from 85dB efficient speakers to 91dB efficient speakers is equivalent to quadrupling your amplifier output.

The best stabs at useful, objective metrics have come from private entities like THX and Audioholics themselves.

I don't know the intricacies of THX's various standards, but as far as I know they boil(ed) down to: "ability to play at 85dB with 20dB dynamic peaks at acceptable distortion levels" which, dammit, is pretty genius because to hell with all the other numbers... that is essentially the end goal we're trying to achieve. Audioholics' subwoofer rating categories are similarly useful because they answer the only question that really matters: is this subwoofer going to perform in my room or not?

Not sure what the best outcome would even be here. Somewhat useful yet mediocre standards, widely enforced? Or genuinely useful standards applied to only a tiny fraction of the marketplace?

Ideally, we'd see a genuinely great standard enforced by the FTC. But I doubt it. Too much industry pushback.

 

[lovinthehd]

Isn't the FTC prevented from using actual science/scientific evidence just as the other agencies are required to ignore such now?

 

[randyb]

Dennis Murphy knows the history of the FTC power ratings. Perhaps, he will post to this thread.

 

[M Code]

The FTC moved back from the power amplifier status many years ago... Next the EIA took it up and came went through their electrical standards committee which was made up of Panasonic, Sony and Bose called EIA 490...
The big carry over complaint was that the # of channels and power level driven was relaxed down to 1/8th power. Being that most AVRs were 7.1 thats where the (2) channel driven standard came about, 1 channel driven to rated power, THD, bandwidth the other 6 channels to 1/8th power. So (2) channels driven is now the defecto norm.

Once the FTC backed out the industry went out of control, here is a (1) example..
Here is an amplifier rated @ a KW for $135..
https://www.amazon.com/dp/B00LLEGZ76/ref=psdc_11974031_t3_B078YKXYK8

Also car amplifiers are out of control, see this example..
Here is a 1500W one for $57..
https://www.amazon.com/Pyle-PLA2200-2-Channel-Bridgeable-Amplifier/dp/B000CHRK6S/ref=sr_1_12?s=car&ie=UTF8&qid=1522710016&sr=1-12&refinements=p_4:Pyle

Bottom line..
Stay with established brands....

Just my $0.02...

 

[M Code]

Situation is out of control..
Has been for many years when the FTC backed away. In fact, in many instances the published power output specifications found in brochures and websites are frequently done by the advertising/marketing boys with no input from the engineering/design department...

Just my $0.02...

 

[Bucknekked]

if a potential amplifier/AVR purchaser would do a simple search on the audioholics forums and perhaps enter a post or two, I would wager most of the bad purchases could be avoided. If you come here, look around, ask a few questions, you will get solid advice with only mild brand bias. The crap out there gets called out pretty quickly in here and the good stuff gets plenty of praise. Just try and slip a bad amp's numbers passed @PENG .

 

[Dennis Murphy]

Although I retired from the FTC in 2010, I have kept up with developments there, and despite the evil DT may be doing to other agencies, he has had no impact on the FTC. The Commission continues to require scientific evidence for product performance claims. The problem is simply that the FTC doesn't have the in-house expertise or the resources it would take to develop a reasonable power rating system for multichannel receivers, particularly since the industry itself is deeply divided on an appropriate approach. I tried at least 3 times to obtain helpful input from the industry and came up empty handed each time. In the end, I simply recommended that the Commission interpret the FTC Rule to mean that the most prominent power disclosure for all amplifiers, irrespective of the number of channels, be the standard stereo rating of 2 channels operating simultaneously at full rated continuous power with a stated power bandwidth and maximum total harmonic distortion, all into 8 ohms. Manufacturers are free to provide additional power ratings once this spec is disclosed. It would appear that a number of manufacturers are violating this requirement, and I intend to pass on this information to the FTC's Division of Enforcement.

 

[gene]

This is feedback I received from this article by Bill Dudleston of Legacy Audio who gave me permission to post in this thread:

Nice job on all aspects of this article. Sharing of power supplies certainly limits the output of receivers.

I would think the receiver makers for $25 more could beef up the power supplies to rated levels, or rate all power legitimately at under 1% distortion with all channels driven for a specified time duration. This time period could be as short as 5 to 15 seconds for music applications. Most electronic church organs today have only 150watts driving the pedal notes, even in larger cathedrals.


Perhaps they should use Bob Carvers old trick of inverting the channel inputs on the right bank of channels and flipping the binding post polarity labeling. Best use of power supply capability for sure. We did this internally on DVC subs for years. Kills hum on long RCA cable runs also. Just have to know that black does not infer ground.


Regarding pre-heating, when we test a fresh batch of our raw subwoofer driver, we usually examine a batch of 150 units at a time. Multiple ten-second sweeps 10 Hz to 500 Hz, followed by up to 50 volt pulses with excursions exceeding an inch each case. We also run modulated simultaneous tones of 25 and 70 Hz looking for buzzes and rubs. We are very finicky and usually reject 10 to 12% of the drivers for mechanical noises due to rubs or non-centric coils or noisy spiders. That is a good days’ work for any amplifier for sure.


It may be of useful interest that these latest high power class D amps (ICEpower in our case) get through the testing periods handily whereas my trusty class A/B amps require a cool down after twenty pieces or so, despite their massive heat-sinking and 20 output transistors per side. The recent class D high power designs don’t go through fuses like the A/B units either.


Thanks for holding this issue up to a brighter light. Compliance to guidelines is the obligation of each manufacturer. Hopefully our industry will not allow rating to become meaningless as the car audio market has.
- Bill Dudleston
Legacy Audio

 

[Speedskater]

'Jonny2Bad' just wrote this in another forum:
The original FTC (1974) Rule required a pre-conditioning at one-third rated power into each rated impedance.

The current FTC rule has been modified (about 20 years ago, under pressure from audio manufacturers, in particular Home Theatre manufacturers) and now requires a pre-conditioning at one-eigth rated power into each impedance.

I avoid confusion by just referring to a one-third pre-conditioning as complying with the "FTC (1974) rule" so as not to confuse it with the currently enforced power rule, which I refer to as "FTC (2000) rule".

This distinction is helpful as both (and all subsequent versions) are technically called "FTC 16 CFR Part 432" and "Trade Regulation Rule Relating to Power Output Claims for Amplifiers Utilized in Home Entertainment Products."

Although not really related to your post, it is also worth remembering that the FTC 1974 rule also specified that the most prominently displayed advertised power output be rated into 8 ohms impedance only (even if the amplifier was designed primarily for output into other impedances). For other impedances, power claims had to be in smaller / less prominent text. The FTC (2000) rule also eliminated this impedance limitation, allowing ratings into other than 8 ohms to be the promeinent advertised rating. Similarly the requirement for power to be over a 20~20,000Hz power bandwidth was eliminated, and power could now be specified into 1KHz alone.

Finally the requirement that advertised power be at a specified THD distortion level was eliminated, although it was assumed this would only affect High End vacuum state amplifiers of greater than 1% THD where buyers were not as significantly concerned with very low distortion (and text specifically stating that was expressed in the rule change release), it was not anticipated it would lead to the (unspecified) 10% THD ratings we see now with many transistor designs, especially offshore eBay boards.

In all cases an amplifier had to survive the pre-conditioning and then meet the rated power output without issue; if there was any interruption of service over that time period, no power claim into the impedance under test could be made at any place in advertising or in a specification sheet.
__________________
" ... Go back to the beginning of a technology before the priesthood was established; that was the time when people were communicating information, not proving why there needs to be Priests. This is why the old texts tend to be so good. ..."

 

[BoredSysAdmin]

Gene, It's solid article for most part and I do agree that in Ideal World FTC should intervene and better regulate this issue, however Russian hackers aside(but not FTC, but this is matter for another gov agency which also 3 letters and starts with F) as Dennis very correctly stated - FTC is very much understaffed and under-budgeted. This is done on purpose by influence of very large lobby groups who obliviously not interested in consumer protections, quite the opposite.
So recent Russian election and policy meddling aside (again, matter for other agencies), IMHO FTC should focus it's limited resources at keeping ISPs at bay, especially since current FCC clearly wants FTC to be in charge of regulating ISPs.

 

[NickMoore]

You are not wrong at all for calling out Lyngdorf on the minimal power rating disclosure on their latest integrated amp, the TDAI-3400. But note that this product was just announced within the past few weeks, and probably isn't even available for sale quite yet. The full owners manual has not yet been published. In the past, Lyngdorf has published specs "in accordance with AES-17" in the owners manual.

The TDAI-3400 appears in every way to be a refinement of the predecessor TDAI-2200, which had similar features and power ratings, but specified with THD+N at 1KHz, the same as John Atkinson's measurements at Stereophile. The owners manual for the TDAI-2200 with more inclusive power, distortion, noise, and bandwidth specs at 4/8 ohms is still available on Lyngdorf's site. Page 34.

I own the TDAI-2200 in my system "B," and I can tell you that one is a genuine muscle amp, a real cool-running beast. I bought it because the RoomPerfect automated EQ system immaculately cleaned up a very tricky semi-open 30'x14'x12' room we used to have, combined with highly compromised placement (WAF, immovable large furniture) of my Sonus Faber Cremona M speakers.

Whatever disadvantages this implementation of Class D may have, in that system in that room they were completely overwhelmed by the fine performance of the preamp/DAC/EQ.

 

[PENG]

'Jonny2Bad' just wrote this in another forum:
The original FTC (1974) Rule required a pre-conditioning at one-third rated power into each rated impedance.

The current FTC rule has been modified (about 20 years ago, under pressure from audio manufacturers, in particular Home Theatre manufacturers) and now requires a pre-conditioning at one-eigth rated power into each impedance.

I read and downloaded the white paper, and I actually felt the change from 1/3 to 1/8 was the right thing to do. Insisting on the 1/3 rated power preconditioning may sound reasonable when 5,7,9,11 channel amps are not very popular. Besides, as the rationale stated by CEMA members, the original intent was not so much about QA but more about bring the components up to temperature.

IMO to insist on the large heat sink or fans requirements that won't practically make a difference for actual in home use would make less sense. Reality is, at a given budget, the manufacture has to pick and choose what to keep and what to give. So it is better to keep better quality components that affect audio quality than bigger/heavier components to deal with thermal issues.

 

[PENG]

You are not wrong at all for calling out Lyngdorf on the minimal power rating disclosure on their latest integrated amp, the TDAI-3400. But note that this product was just announced within the past few weeks, and probably isn't even available for sale quite yet. The full owners manual has not yet been published. In the past, Lyngdorf has published specs "in accordance with AES-17" in the owners manual.

The TDAI-3400 appears in every way to be a refinement of the predecessor TDAI-2200, which had similar features and power ratings, but specified with THD+N at 1KHz, the same as John Atkinson's measurements at Stereophile. The owners manual for the TDAI-2200 with more inclusive power, distortion, noise, and bandwidth specs at 4/8 ohms is still available on Lyngdorf's site. Page 34.

I own the TDAI-2200 in my system "B," and I can tell you that one is a genuine muscle amp, a real cool-running beast. I bought it because the RoomPerfect automated EQ system immaculately cleaned up a very tricky semi-open 30'x14'x12' room we used to have, combined with highly compromised placement (WAF, immovable large furniture) of my Sonus Faber Cremona M speakers.

Whatever disadvantages this implementation of Class D may have, in that system in that room they were completely overwhelmed by the fine performance of the preamp/DAC/EQ.

I think the Lyngdorf, or other digital amps do need different rules/standards, or the existing ones be revised to reflect their different needs. It is not fair to subject such modern design to the ancient FTC requirements created when consumer digital amplifiers were not commonly found. There were class D amps at the time, and I am sure people argued for exceptions for those amps too, but the Lyngdorf amps are certainly much more digital than a regular so called class D amp.

 

[M Code]

I read and downloaded the white paper, and I actually felt the change from 1/3 to 1/8 was the right thing to do. Insisting on the 1/3 rated power preconditioning may sound reasonable when 5,7,9,11 channel amps are not very popular. Besides, as the rationale stated by CEMA members, the original intent was not so much about QA but more about bring the components up to temperature.

IMO to insist on the large heat sink or fans requirements that won't practically make a difference for actual in home use would make less sense. Reality is, at a given budget, the manufacture has to pick and choose what to keep and what to give. So it is better to keep better quality components that affect audio quality than bigger/heavier components to deal with thermal issues.

We know the original FTC statue(73) well as we testified with the FTC when they prepared the original draft. Many things have changed, back then the industry was stereo not multichannel, though there were a few quad products available. The basic requirement of 1 hour preconditioning @ 1/3 power was to get things hot, 1/3 power puts a significant strain on the power supply. The original FTC statue called for 1 hour preconditioning to be continuous that was later relaxed so that the amplifier could cycle on/off accumulating 1 hour.
Back in the mid/late 70s very few products could meet the FTC conditions especially the component power amplifiers from Crown, Phase Linear they tried improvising some kluge fan arrangement hanging on the heat sink with poor results. But the real challenge was the super powered receivers from Technics, Pioneer and Marantz, the only brand meeting its published specs under the FTC statue(73) was Marantz. As their super receiver (2500 & 2600) used a very innovative heat tunnel from their pro amplifier 510 design. Marantz single handily challenged the competition and even got Pioneer to cease/desist certain advertising. In the end, all was in vain, as the FTC moved on to other things leaving things up to to the EIA & CEA. So now we have the complete chaotic mess of misinformation and just outright BS..

Just my $0.02...

 

[PENG]

We know the original FTC statue(73) well as we testified with the FTC when they prepared the original draft. Many things have changed, back then the industry was stereo not multichannel, though there were a few quad products available. The basic requirement of 1 hour preconditioning @ 1/3 power was to get things hot, 1/3 power puts a significant strain on the power supply. The original FTC statue called for 1 hour preconditioning to be continuous that was later relaxed so that the amplifier could cycle on/off accumulating 1 hour.
Back in the mid/late 70s very few products could meet the FTC conditions especially the component power amplifiers from Crown, Phase Linear they tried improvising some kluge fan arrangement hanging on the heat sink with poor results. But the real challenge was the super powered receivers from Technics, Pioneer and Marantz, the only brand meeting its published specs under the FTC statue(73) was Marantz. As their super receiver (2500 & 2600) used a very innovative heat tunnel from their pro amplifier 510 design. Marantz single handily challenged the competition and even got Pioneer to cease/desist certain advertising. In the end, all was in vain, as the FTC moved on to other things leaving things up to to the EIA & CEA. So now we have the complete chaotic mess of misinformation and just outright BS..

Just my $0.02...

1/3 rated power for 1 hour is a thermal challenge for today's 7-9 channel amps, let alone AVRs that could have 7 to 13 channels. In fact I think it is very tough for even a lot of 5 channel class AB integrated or power amps to handle the heat without external cooling.

On the other hand, even the mid range AVRs can do, and verified in bench tests by AH and S&V, more than 1/3 rated power into 8 ohm, with 5 and up to 7 channel driven continuously (not literally continuous, but probably 5 minutes at the most). So again, it makes more sense to relax the 1/3 rated power pre-conditioning requirements and 1/8 seems reasonable, even for the 13 channel Denon AVR-X8500H. Without that change, today's AVRs would have to be much larger, heavier (higher shipping costs) and likely have multiple fans. I think the AVR-X8500H already has at least two internal fans as it is.

 

[Matthew J Poes]

Hey Gene, great article. James Larson (@shadyJ) mentioned that you wrote this article and we had a side conversation about it. As a separate issue for the FTC regulations, in general I think amplifier specmanship gets a little confusing for most. In some ways having good basic knowledge of these tests would be a big boon for the average consumer (or at least your readership).

I am not an engineer, but I have been building and measuring amplifiers for years. I recently began reviewing products for my group, AV NIRVANA, and in the course of some recent reviews, ran into some discrepancies in amplifier specs from very reputable companies. In my discussions with the folks at NAD, Paul Barton, Bruno Putzey, I began to see an interesting problem. Where's the line? You of course call out companies who have burned past that line so far as to be advertising fairy dust specs. What I was dealing with was the idea of just defining clipping itself. NAD defined clipping as .1%, Bruno defined it as 1%, Paul did the same. In the amplifier in question, this lead to a 20 watt difference (80 vs 100). Same amp of course. To you or I, this is a meaningless difference, but it certainly is confusing to the average consumer.

Now with so many amplifiers coming about that are absurdly low in noise, this becomes a more interesting question (even if not so important sonically). Look at the THX AAA based amplifier from Benchmark, the SPL amplifiers, the Hypex NCORE and you see amps with noise and distortion specs near the limits of the common audio precision measurement devices. Where the knee in the distortion plot is at .001% or sometimes even .0001% THD, so by .1% we are well into the vertical. With these amps the vertical is a shear wall, the difference in power between .0001% and .1% at the knee is a handful of watts. None the less, I've always wondered if a more empirical method could be used to avoid rating an amp to far into the vertical. The use of a rate of change in distortion per watt, the slope basically.

That thinking (which I've had before) brings up the other problem, where is the knee? In a lot of amps, especially most typical low noise Class A/B or Class D amps, the Knee is very obvious. With a lot of unusual Class A amps, low feedback or no feedback amps, the distortion and noise rise with output more evenly and actually surpass .1% before the knee becomes very obvious. In some cases, the knee is not so obvious. A lot of Pass amps would rate out at 2-3 times their actual rated power if you used a .1% rule, and my "Knee" rule would be hard to apply as there is no obvious Knee. Class H has two or three knees, but of course, the .1% or the 1% rule would work fine.

The other question I have related to this is the audibility piece. My understanding (<=remember, not an engineer) is that clipping normally is associated with a rise in 2nd order distortion. In that case, it would seem that the use of THD is generally ok, especially with typical amps. What I wonder is if it makes sense to use a distortion audibility metric that is better than THD however. So the question really is, does clipping always cause a rise in 2nd harmonic, or could some amp topologies show a rise in higher order distortions while still having very low 2nd harmonic, but where the slight clipping is associated with a more audible change in the sound?

Class G amps: I've heard/read from Carver (I believe) that Class G amps interact with the reactive load and put out more power under those conditions. Never understood this, nor can confirm its even true. It was used as an argument for why their sub amps (and Parts Express Class G amps) didn't meet power specs with a resistive test load. Is this true? If so, should a reactive load be a testing option? I think this would be difficult to do. I know that in the guitar world there are power soaks made from voicecoils that are claimed to handle 100's of watts, maybe an actively cooled coil could be made to allow high power testing with a reactive load?

Final Thought here, It seems that Class D amplifiers may need a special test, or a better standardization of the test. I've seen some really odd results of lesser amps, including problems due to ultrasonic noise. Further, some amps which would pass with flying colors at 1khz oscillate terrible. The Behringer DSP amps that are so popular are a good example, they oscillate at high frequencies and aren't great amps for full range use (yet some people love them ).

Now as for the ACD, has there been any thought about developing a more real world test procedure. Maybe 3 channels driven to max but the rest driven just a percentage that reasonably reflects what we see in realistic use? Maybe 7 channels full out and 4 driven (in the case of 11 channels) partially. I've always thought the ACD is a little too extreme. Even with the advantageous of DIY I've never built a power supply for a multi-channel amp to allow all channels to reach their full power into a low impedance load at the same time, the power supply would simply be too big and expensive (for high powered amps anyway).

Related to that, I've also learned the hard way that switching supplies have changed how we must design amps. I'm sure the engineers know this, but I'm not sure its always being put into practice. When I built my first amp using a switching supply, the amp modules could do around 500 watts into a 4 ohm load each. They were Class A/B amps so the supply needed to be about 1500 watts to allow full power. I bought a 1500 watt switching supply made in Spain for audio purposes and customized to my needs. It would not allow the amp to reach full power into an 8 ohm load, shutting down when the amp reached around 150 watts per channel! I replaced it with a 1200 watt supply from another company who I am confident designed it right and specified it accordingly, and once again I ran into the same problem. What I've since been told is that these power supplies basically hit a brick wall and can't produce any more current while regulating the voltage. It isn't like a linear supply. As such, you need to over-spec the supply by 2-3 times (that was the suggestion of this second manufacturer).

 

[M Code]

1/3 rated power for 1 hour is a thermal challenge for today's 7-9 channel amps, let alone AVRs that could have 7 to 13 channels. In fact I think it is very tough for even a lot of 5 channel class AB integrated or power amps to handle the heat without external cooling.

On the other hand, even the mid range AVRs can do, and verified in bench tests by AH and S&V, more than 1/3 rated power into 8 ohm, with 5 and up to 7 channel driven continuously (not literally continuous, but probably 5 minutes at the most). So again, it makes more sense to relax the 1/3 rated power pre-conditioning requirements and 1/8 seems reasonable, even for the 13 channel Denon AVR-X8500H. Without that change, today's AVRs would have to be much larger, heavier (higher shipping costs) and likely have multiple fans. I think the AVR-X8500H already has at least two internal fans as it is.

As I mentioned the original FTC statue was created back in the days of stereo not multichannel, so yes absolutely some revisions and updates are needed for the multichannel products and those with Class D solutions. IMHO.. U can't compare the original standards with the testing MO of S&V.. S&V does no preconditioning and typically measure only @1kHz. But here something is better than nothing.

Since we have developed/sourced AVRs for some of the mentioned major brands, I can honestly state that certain published power output specifications are BS.. I know of multiple instances of certain major brands where the published power output specs were created by the sales/marketing teams without any confirmation by the design/engineering groups. Another point to keep in mind is that published specs become part of the product and are covered under the respective warranty conditions.

Regarding test results by S&V and others, note that the submitted test samples are often tweaked and/or handpicked to be of the highest yields. So a stock unit purchased from a normal seller that its actual power output specs may vary by up to 40% lower from the published specs.

Just my $0.02...

 

[PENG]

As I mentioned the original FTC statue was created back in the days of stereo not multichannel, so yes absolutely some revisions and updates are needed for the multichannel products and those with Class D solutions. IMHO.. U can't compare the original standards with the testing MO of S&V.. S&V does no preconditioning and typically measure only @1kHz. But here something is better than nothing.

Yes, and we are almost saying the same thing, just a little differently. No I am not trying to compare S&V or AH's methods to FTC's, totally different things.