Has the FTC Failed Consumer Audio Regarding Amplifier Power Claims?
What is the FTC?
The Federal Trade Commission (FTC) was established under President Woodrow Wilson in 1914 to protect consumers against trusts via the elimination and prevention of anticompetitive business practices, such as coercive monopolies. Section 5 of the Federal Trade Commission Act, 15 U.S.C. § 45 grants the FTC power to investigate and prevent deceptive trade practices. According to their own commission, federal law states that an “ad must be truthful, not misleading, and, when appropriate, backed by scientific evidence”. This sounds similar to our very own mission statement of "Pursuing the truth in audio".
The same standard is said to apply to all forms of media, be it print, online, mail, or on billboards, etc. The FTC supposedly closely examines advertsing claims that can affect consumers’ health or their wallets – claims about food, over-the-counter drugs, dietary supplements, alcohol, and tobacco and on conduct related to high-tech products and the Internet.
This all sounds great. We have an advocacy in our own government to keep the manufacturers honest. But do they really? The focus of this article is to determine that answer in the narrow scope of how it relates to the consumer audio industry, particularly power claims in amplifiers and AV receivers. This article does NOT attempt to judge sound quality of different products based solely on power ratings.
Join our Movement by signing our TiP (Truth in Power) Petition NOW!
FTC on Amplifier Power Claims
On May 3, 1974, the FTC instituted its Amplifier Rule to combat the unrealistic power claims made by many hi-fi amplifier manufacturers. "Unrealistic" meaning manufacturers specifying power solely as peak, dynamic of summed two or more channels would not be tolerated. This rule prescribes continuous power measurements performed with sine wave signals for advertising and specifications of amplifiers sold in the US. This rule was later amended in 1998 to cover self-powered speakers such as those commonly used with personal computers or portable devices.
Editorial Note on Powered Subwoofer Claims by Steve Feinstein
Probably the biggest omission by the FTC are the bogus, unverifiable power claims of powered subwoofers. The customer buying a $60 set of computer speakers doesn’t know or care if they’re 25-watt or 150-watt. But someone shelling out $1,500 on a powered sub that goes flat down to 20Hz deserves to know and wants to know what that “1000-watt” amp really does.
There is a very legitimate point to be made that power ratings are irrelevant in a ‘closed’ system—a system that is self-powered, to which external speakers cannot and never will be connected. Power ratings are really only relevant in ‘open’ systems, those where external 3rd-party passive speakers will be connected to the amplifier in question. Still, above a certain price/performance/sophistication level, the customer (say, an SVS sub owner) wants to know what the product really does.
Typically, an amplifier's power specifications are calculated by measuring its output voltage (RMS), with a continuous sine wave signal, at the onset of clipping, stated as a percentage of total harmonic distortion (THD), typically at 1% into a specified load resistance of 8 or 4 ohms (depending on how the amplifier is rated). Continuous power measurements do not actually describe the highly varied signals found in audio equipment but are a reasonable way of describing an amplifier's maximum output capability. For audio equipment, this is nearly always the nominal frequency range of human hearing, 20 Hz to 20 kHz.
=> Example: 100 watts/ch, 2 channels-driven at 8 ohms from 20 Hz to 20 kHz < 1% THD+N
As a quick refresher using Ohm’s Law we get: P = V*I where Vrms*Irms = Pave = V^2 /R. So for an amplifier to be rated 100 watts/ch into an 8-ohm load, it must be able to swing 28.3Vrms unclipped.
Power vs Distortion Graph for Denon AVR-X3300W AV Receiver
It's important to understand how to read a power vs distortion graph when assessing amplifier power. The region where the lines are horizontal represents clean (unclipped) amplifier power. As the traces begin to go vertical, distortion goes up dramatically and anything to the right of the vertical lines represents gross distortion. With just two channels driven, the AVR-X3300W exceeded its 105 watts/ch rating. But with five channels driven, the receiver was unable to deliver rated power though it still managed an impressive 88 watts/ch (1% THD+N).
When you see AV recevier companies rating power at 1% or 10% THD, just realize they are rating power out of the linear operating portion (horizontal line) of the power vs distortion curve and are either doing it at the knee or where distortion dominates and increases exponentially as it goes up vertically on the curve.
Editorial Note about Peak Power
Peak momentary power output and peak music power output are two different measurements with different specifications and should not be used interchangeably. Manufacturers may often use their own standard system of measurement or nomenclature to derive peak or max power but usually with an unknown method of how they derived it. The Federal Trade Commission attempted to put an end to this with Federal Trade Commission (FTC) Rule 46 CFR 432 (1974), affecting Power Output Claims for Amplifiers Utilized in Home Entertainment Products.
Understanding AV Receiver Power Ratings YouTube Discussion
16 CFR Part 432 is the Trade Regulation Rule Relating to Power Output Claims for Amplifiers Utilized in Home Entertainment Products. In this section, it is declared that all "associated" channels be driven at full power and bandwidth for up to 5 minutes. A preconditioning period of one hour shall be done prior to measuring full power by driving ALL channels at 1/8th rated power at 1kHz.
Editorial Note on De-rating Power Ratings by Steve Feinstein
This was originally 1/3 rated power, in 1974. The FTC had no idea that 1/3 power was smack dab in the middle of a Class AB amp’s least efficient operating range and as a result, all the amps under test ran extremely hot during the preconditioning—even before the actual testing! Many of these amps failed during the preconditioning! The manufacturers either had to de-rate them so they wouldn’t run as hot at a lower power level or they had to redesign them with additional heatsinking. The Dynaco SCA-80—a very popular integrated amp at the time—had to be de-rated from 40 wpc to 30 wpc, because 1/3 of 40 was too hot for the amp to handle. Be wary of bureaucratic interference, even when well-intentioned!
The ruling recognizes that multi-channel amplifiers beyond two channels exist but leave it up to the manufacturers to decide which channels are "associated". In fact, the ruling even recognizes that running ALL channels simultaneously may be too taxing on an AV receivers common power supply. However, it still is implied that at least two of the channels (namely left/right front stereo pair) should be associated and tested as such. In fact, back in 2002, when the Consumers Electronics Association (CEA) noted that presently there was no industry consensus on testing, measuring and specifying power output of multi-channel amplifier products. In the absence of a voluntary industry standard that adequately addressed multi-channel amplifiers, the CEA suggested that "associated" channel groups could be tested, though not all groups simultaneously. This was left for further study to be revisited in 2008.
As of 2008, the FTC acknowledged that although the CEA issued a voluntary standard designated CEA-490A, which pertained to measuring multi-channel amplifiers with "associated" channels, wide spread adoption of the standard in advertisements of product specifications was not achieved and as a result there was no further ruling. Thus, the FTC would NOT enforce multi-channel amplifier power testing beyond two "associated" channels.
A HTIB with a claimed "1000 watts" of power
Editorial Note from an Industry Veteran about HTIB Power Claims
The industry has been playing the power game for years. Also as explained in this article, so many things have changed that is impossible to come up with a consistent standard especially with the appearance of multi-channel amplifiers and receivers that offer 9,11, or more channels of amplification. "ACD" is becoming a nearly impossible standard to achieve unless a manufacturer wants to cut their power claims by 50 to 60%. And so it has become a free for all where every company plays with the conditions in their declaration of watts.
The power game was actually worsened a few years back by some big box mass merchandisers. in the glory days of HTIB's (Home Theater In a Box). In one brutal example, a number of manufacturers were asked to submit samples of a complete 5 speaker, subwoofer and control section HTIB that delivered 1000 total watts. The retailer required that the 1000 watt power be printed on the display box in large print along with the other features of the system. The entire system was going to sell for $249.00! Due to manpower, workload and budget restrictions the FTC was powerless to do anything about these false declarations.
The spillover from those declarations has had its effect on unsophisticated consumers who were astounded to see power ratings on real AV receivers that were on display in legitimate hi-fi retailers, especially when the brand names of the HTIB's were the same as the brands in the smaller hi-fi shops.
So Where Are We at Now with Power Ratings?
Best I could tell is all work has ceased as of 2008 from the FTC and CEA regarding how to measure multi-channel amplifiers beyond two channels. However, it seems clear that the ruling of at least two channels rated should be enforced and agreed upon by amplifier manufacturers regardless of whether or not their products have 2, 5, 7 or more amplifier channels. One would assume that when a consumer buys such a product, the power ratings specified by the manufacturer should be with at least two channels driven at full bandwidth under a specified load impedance (8 or 4 ohms, typically) and under 1% THD+N. This assumption would have been correct when two channel amplifiers dominated the audio marketplace, but is it still a safe assumption today when we've got manufacturers cramming 7 or 9 channels into an Atmos receiver for under $1000 retail price? What about the new crop of efficient Class D power amplifiers?
Join our Movement by signing our TiP (Truth in Power) Petition NOW!
Has the FTC Failed Consumer Audio Regarding Amplifier Power Claims? P2
Up until the recent explosion of Dolby Atmos in the consumer marketplace, most AV receiver manufacturers were rating power with two channels driven at a specified distortion (usually <0.1% THD+N) at 8-ohms. Only a rare few companies (i.e. NAD) would also specify an "All Channels Driven (ACD)" rating. However, things seemed to get really mucky once manufacturers stamped Atmos on their receivers and started cramming 9 or more channels into the same sized chassis, with the same sized power supply that their 7-channel predecessors had only a year prior. Instead of getting a 2-channel rating at less than a specified distortion into an 8-ohm impedance, we started seeing something far more dubious.
It started with Onkyo, but others followed suit shortly after. Instead of rating at 8 ohms, 2 channels driven at a low distortion level, they started rating power with only 1 channel driven, at 6 ohms, at near clipped distortion levels. The reality of the situation is rating only 1 channel driven isn't very realistic of how a consumer uses an amplifier or receiver since both channels typically draw nearly the same power simultaneously with stereo program material. Also, rating an amplifier at say 0.1% THD+N vs 10% THD+N represents very different behavior of that amplifier. The 0.1% case is arguably an inaudible amount of distortion while the 10% case is not only visible on an Oscilloscope as a clipped wave form but is also very audible. It's at the point where the amplifier can no longer supply additional voltage and instead is turning a sine wave into a square wave with very high audible 2nd order harmonics and potentially damaging signal to the loudspeakers tweeters. Again this is power rated on the vertical trace in the power vs distortion curve previously mentioned.
This allowed the manufacturer to inflate power claims by a good 35-40%, which looks impressive to the uninitiated. More power must be better right? Sadly, most casual shoppers don't realize what's going on and come home with a much less powerful product than they thought they’d purchased.
When the first generation Atmos receivers popped up, some manufacturers were only listing the 1-channel power measurement. After we called them out on it, they all changed their websites in unison to list both ratings methods (1 channel, 1kHz @ 6 ohms clipped, 2 channels 1kHz per FTC). Though, the FTC states full power bandwidth must be specified, not just one discrete frequency (1kHz).
For an expanded discussion on this topic, read: Power Manipulation in Dolby Atmos AV Receivers
Onkyo TX-RZ3100 & Pioneer SC-LX901
MSRP: $3,099 & $3,000, respectively
Onkyo and Pioneer Both Showcasing inflated 1CH power rating above the 2CH FTC Rating
Still, some manufacturers are a bit craftier and stamp a power sticker on the front panel of their receivers. Take for example the new Denon AVR-X8500H 13.2 channel flagship receiver. That 260-watt sticker on the front panel looks impressive. Denon got this magic number by rating only 1 channel driven, at 6-ohms and 10% THD+N (hard clipping). This is a completely ludicrous way of rating power, similar to peak power rating that FTC Rule 46 CFR 432 warned against. The AVR-X8500H is already a very powerful receiver when honestly rated at 150 watts/ch with 2 channels driven. It's doubtful most consumers plopping down $4k on an AV receiver wouldn't at least be aware the 260-watt rating is inflated, so why bother if it only serves to cause doubt among your core customers?
Denon AVR-X8500H 13.2CH AV Receiver with 260 watt front panel sticker
Yamaha does similar with their JEITA power rating (1kHz, 1 channel, 8 ohms, 10% THD), but at least they don't slap a sticker on the front panel. They also disclose 2 channel power at 1kHz and full bandwidth with specified 8-ohm load impedance and distortion levels. However, not too many years ago, they used to give you a summed power rating of all channels (i.e. 100 wpc x 7 = 700 watts), despite the fact that the receiver was incapable of delivering that power with all channels driven. At least they've moved away from that rating style in their more recent product releases from what we've seen.
Yamaha RX-A3070 Power Ratings various methods with 2CH ratings shown first
NAD T787 Receiver
NAD T787 7CH Receiver is ONLY major brand rating ACD Power
Now in comparison, look how NAD rates their AV receivers. Full disclosure of power per FTC for ALL channels driven. They are stating rated power more honestly at 120 watts/ch x 7 then you're getting with the examples above with only 1 or 2 channels driven at 6 ohms, 1kHz and high distortion. Sure, the number doesn't look as impressive, but it's real. Bravo!
The reality is the Denon receiver previously mentioned has a pretty beefy power supply (900 watts) spread across 13 channels, while the NAD has around a 1100-watt power supply spread across 7 channels. The latter clearly can hit its more honestly rated 120 wpc x 7 while the Denon cannot do 150 wpc x 13, let alone for 7 channels. NAD rates this receiver as 200 wpc x 2 and de-rates for all channels driven. Denon could have simply rated their AVR-X8500H 150 wpc x 2 and probably still achieve 115-120 wpc x 7 based on the size of the power supply and how their predecessor 7200WA performed on the bench. This is an example where both products are very capable despite one manufacturer being more conservative in how they rate the power of their amplifiers. Manufacturers know this, but they're banking on the fact that you may not know as much, in order to make their product stand out among its competitors as being more "powerful."
Loose power specifications aren't limited to just AV receivers. We are also seeing this trend with dedicated power amplifiers, most commonly with Class D topologies. The reason for this is most Class D amplifiers can easily deliver high power ratings at 1kHz, 8 ohms, but some have varying performance based on load impedance. We've seen older ICE modules, for example, that did great at 1kHz at 8 ohms but couldn't deliver more than 1/3 rated power into 4 ohm loads above 3kHz. This is something often missed in most AV review magazines that only test at 1kHz and something that isn't usually disclosed in manufacturer specifications of these types of products.
Lyngdorf TDAI-3400 Integrated Amplifier
Here is an example of a very expensive two-channel integrated amplifier from a company named Lyngdorf. Their 2 x 400 watt (4 ohms) and 2 x 200 watt (8 ohms) power ratings look impressive upon first glance. But, when you look closer, they don't disclose bandwidth or distortion at full power but instead, only at 1 watt. For a product of this caliber, that's simply unacceptable especially when many of their competitors still using Class AB amplifier topologies give full disclosure of power. It is possible that this product can deliver full rated power at full bandwidth with both channels driven. But, you'd never know it from their poor specsmanship.
The next example can be seen from a company called Wyred4Sound. Their SX-1000R Monobloc retails for $1,799/ea and is rated for 625 watts into 8 ohms, and an impressive 1225 watts into 4 ohms. Again, no specifications for distortion or bandwidth are given.
Wyred4Sound SX-1000R Monobloc Amplifier
These may be great products and I'm not debating their fidelity. However, the manufacturers should be embarrassed to offer so few objective performance metrics. As Dr. Floyd Toole says, "You usually get more useful information from the sidewall of a tire than you do from loudspeaker manufacturer specifications...." I'm going to extend the usefulness of that phrase to how Class D amplifiers are being specified and sadly how the FTC is letting this go under the radar.
Monoprice Monolith-7 Specifications
Yet when we look at relatively inexpensive amplifier from Monoprice ($1,799 for 200 wpc x 7), full disclosure of power is given for ALL channels driven per FTC testing protocol. In fact, their website even shows full test data from the same Audio Precision audio analyzers we use for our product reviews! It makes you wonder just how many of these "high end" amplifier companies have access to this type of test gear or if they're just taking amplifier modules from chip vendors and just stuffing them into a box and hoping for the best.
Outlaw Model 5000 5CH Amplifier
If you take a look at every amplifier Outlaw Audio sells, they too give full disclosure of power. In fact, we measured this very amplifier and it exceeded the 120 watts x 5 ACD. How is it possible that a company can offer so much transparency on such an inexpensive product while another manufacturer of a product costing 10 times the amount cannot? Incidentally, both examples disclosing full power are classic AB linear amplifier designs. Again, we typically see the lack of specifications on Class D power amplifiers and hope this article exposes that deficiency in order to nudge manufacturers to be more forthcoming with their power specifications.
So, what have we learned from all of this? Basically, the FTC has bigger fish to fry (like the Russians hacking our election) than worrying about amplifier power claims for consumer audio. Since the work by the FTC to further study how to properly rate multi-channel power amplifier claims ceased over a decade ago, we don't expect much enforcement these days. Also, don't count on most manufacturers to do the right thing and offer full disclosure of power. In fact, some receiver and most HTIB manufacturers are showcasing their bogus power claims via a sticker on the front panel or as the primary power rating in their online product page. Sadly, consumers often have to be extra vigilant on seeking out the true 2CH, full bandwidth, 8 ohm power ratings to not be mislead by these inflated ratings.
Editorial Note about the FTC by Steve Feinstein
The FTC never evidenced any particular expertise for the finer points of audio amplifier design, and that lack of expertise was—and is—apparent in the many loopholes and inconsistencies in their power guidelines. The FTC should have hired experienced audio designers and industry professionals as consultants to implement their rulings, but to our knowledge, this was never done, or if it was, they never said so. Although the initial 1974 effort was well-intentioned, if a bit naïve (per the ridiculous and ignorant 1/3-power preconditioning requirement), their haphazard approach since 1974 makes it obvious that the FTC never really had the technical or organizational wherewithal that was required to do a truly credible, complete job.
At what point does full disclosure even make sense as we start seeing multi-channel amplifiers serving 10 or more channels from a single chassis? The reality is, we don't listen to music or even watch movies with all channels driven. However, that doesn't mean we should just accept inflated power ratings with little to no specifications of how they were derived does it?
At Audioholics, we test 2-channels driven, full bandwidth for 8 and 4 ohm loads and ACD for up to 7 channels at 1 kHz for 8-ohm loads. We also do CEA 2006 dynamic power testing as well to see how capable the amplifier is at delivering dynamic performance similar to how we listen to music. This isn't a perfect test, but it will usually identify shortcomings in an amplifier’s ability to deliver stable power under heavy loading conditions.
For more information, see: Audioholics Amplifier Measurement Standard
As a consumer, it's of paramount importance to read the fine print in how manufacturers are specifying power, so you can make as close to an apples-to-apples comparison as possible. If you see your favorite manufacturer fudging their power ratings like the examples shown herein, it wouldn't hurt to pop them an email asking them to do better. Don't forget to tell them Audioholics told you so. Be sure to vote in our online poll in the associated forum thread. Let your voices be heard!