Power amplifier tests with respect to FTC: 16 CFR Part 432 (July 5, 2024) requirements on output power claims

[Doodski]

If you only saw my backlog of gear to test, you'd understand as well.

LoL... I'm still waiting for a review of the red gaming Sennheiser headphones that I gifted to you about 2 years ago. No biggie I know you are run off your feet and have a very busy schedule and agenda.

 

[amirm]

The concern about enforcement is valid, as previously acknowledged, but dismissing the regulation entirely ignores how these combined measures could finally curb misleading marketing.

By creating an unworkable and useless spec? It can't possibly do that. Tell me why 8 ohm spec is useful to you when vast majority of speakers are 4 ohm.

 

[mhardy6647]

How would a consumer know 50 watts from 100 watts???

Worse than that -- the typical consumer has no notion that 100 watts is, practically speaking, a minimal "improvement" over 50 watts (i.e., 3 dB) -- even if they might, vaguely, know that 3 dB isn't very much difference.

 

[kyuu]

I think even in the "heyday" of hi-fi, a lot of the enthusiasts weren't terribly technically-minded and didn't know much about what any of the specs meant any more than many do now. They simply went to their local shop and bought whatever the nice salespeople sold them, or what they saw and lusted after in some magazine.

 

[mhardy6647]

As a 1970s survivor -- I can assure you that, at the least, power was very important indeed to the emerging market of slightly addled but fairly cash-flush late adolescents that staggered onto college campuses across the US.

The ad above, for example, appeared in that noted, highly specialized audio engineering periodical National Lampoon in October 1977.

 

[mhardy6647]

... or at the other end of the spectrum (from National Lampoon Sep. 1976):
Note the price, "RMS" output power spec... and the bandwidth.

 

[kyuu]

Well sure, they knew they wanted big numbers.

 

[mhardy6647]

Well sure, they knew they wanted big numbers.

Yes, exactly so!
That hasn't changed.

 

[jomo]

Tell me why 8 ohm spec is useful to you when vast majority of speakers are 4 ohm.

Where do you get this information? I just checked Crutchfield floor/bookshelf speakers as a sample and 8 ohm was the most common by a wide margin (340 speakers), followed by 4 ohm (177 speakers). I would consider that their speakers are typical of what the masses purchase in the US.

The "major" reason is much more likely to be apathy of mass market when it comes to technical specs such as watts. It has no meaning to them. I posted early in a thread that a Sony AVR I looked up did not even mention the output power in specs! How would a consumer know 50 watts from 100 watts???

Sony's website has been a mess for quite a while in regard to finding information. With a little effort, you can find rated power in the Specification section of the AVR's Operating Instructions (Manuals).

 

[amirm]

Where do you get this information? I just checked Crutchfield floor/bookshelf speakers as a sample and 8 ohm was the most common by a wide margin (340 speakers), followed by 4 ohm (177 speakers).

From actually measuring 250 speakers. The manufacturer specs are complete nonsense. Example: from Crutchfield (which came from Revel): https://www.crutchfield.com/p_265F228BES/Revel-PerformaBe-F228Be-Metallic-Silver.html

• impedance: 8 ohms

Actual measurement: https://www.audiosciencereview.com/forum/index.php?threads/revel-f228be-review-speaker.23659/

As you see, the impedance is highly variable but gets down to minimum of just 3.4 ohm in bass. It is not remotely "8" ohm until you get to 600 Hz at which point, you don't need anywhere near the power you need in bass.

 

[amirm]

Sony's website has been a mess for quite a while in regard to finding information. With a little effort, you can find rated power in the Specification section of the AVR's Operating Instructions (Manuals).

You wouldn't have seen this kind of mess 40 years ago. It is messy now because no mass market consumer really cares about specs anymore. And they know it.

That aside, here is a random AVR spec from their manual: https://www.sony.com/electronics/su...5cd375e0f9e7103f2b6baa747ed9072/47269061M.pdf

"Amplifier section1)Speaker impedance use 6 ohms – 16 ohms
Minimum RMS Output Power(6 ohms, 20 Hz – 20 kHz, THD 0.09%)90 W + 90 W
Stereo Mode Output Power(6 ohms, 1 kHz, THD 0.9%)105 W + 105 W
Surround Mode Output Power2)(6 ohms, 1 kHz, THD 0.9%)145 W per channel"

Spec claims that you can't even use the thing for the most common impedance in speakers, i.e. 4 ohm! Of course, it works perfectly fine for 4 ohm. Why do they not state that it does? Because it gets too hot under the strict testing of UL. So what they do, just like what FTC will force to happen, is give you bogus specs that are not useful at all.

 

[Old_School_Brad]

Well sure, they knew they wanted big numbers.

The situation remains unchanged today.
The examples shown are good and a bit funny with the 20 W. But I'm sure it'll be on the very conservative side of ratings.

Just like the economy, power ratings have suffered from crazy inflation. We're essentially back to PMPO power.
I blame AVRs for starting this trend and Class D amplifiers for pushing it further with exaggerated figures.

Generally, specifications are unclear not due to a lack of consumer interest, but because no one is taking the initiative to measure according to regulations and there is no penalty.
Today's consumers are caught in this and thus believe they need a 600 W amplifier to pair with their stand-mount speakers. Surprisingly, this 600 W amplifier can supposedly fit in a small cigar box and be conveniently stored away in a cabinet.

What is a watt? Many people are unaware because the definition has been poorly handled and misapplied for such a long time.

Hopefully, the FTC will intervene to enforce its regulations and help get things back on track.

 

[restorer-john]

... or at the other end of the spectrum (from National Lampoon Sep. 1976):
Note the price, "RMS" output power spec... and the bandwidth.
View attachment 425151

It was common with low end receivers and amplifiers to rate from 40Hz as they simply couldn't hit their power and THD at 20Hz due to inexpensive PSUs. But there also was no requirement to specify 20Hz-20K. It was whatever the manufacturer decided. Plenty of amps were power specified from 40Hz-15kHz in the early days (low end ones).

The 20Hz-20kHz is unnecessary as long as the bandwidth chosen is specifically mentioned. But it is what it is now.

 

[mhardy6647]

It was common with low end receivers and amplifiers to rate from 40Hz as they simply couldn't hit their power and THD at 20Hz due to inexpensive PSUs. But there also was no requirement to specify 20Hz-20K. It was whatever the manufacturer decided. Plenty of amps were power specified from 40Hz-15kHz in the early days (low end ones).

The 20Hz-20kHz is unnecessary as long as the bandwidth chosen is specifically mentioned. But it is what it is now.

Yes, indeed, and that was fine... I just wanted to point out the lower power rating and the decreased LF bandwidth (specified at full power) commensurate with the lower price.

The funny thing is that the consumers thought a spec that didn't go to 40 Hz absolutely meant a lower-quality component -- which was a bit narrow minded.
Allowing the manufacturer to pick (and specify) a bandwidth for their "FTC" power rating seems (ahem, seemed) reasonable to me. Very reasonable.

 

[MaxwellsEq]

The funny thing is that the consumers thought a spec that didn't go to 40 Hz absolutely meant a lower-quality component -- which was a bit narrow minded

Especially since their main source of music would have been LPs which have little of any musical content below 40Hz anyway.

 

[restorer-john]

Especially since their main source of music would have been LPs which have little of any musical content below 40Hz anyway.

Very true back then. Until at least 1982 realistically.

I think the FTC has somewhat missed the mark with the mandated 20Hz-20kHz thing. I get it, they want a level playing field, and they know consumers have absolutely no idea, but bandwidth limiting is not evil, as long as it is clearly and prominently advertised. They are damned if they do and damned if they don't.

 

[Old_School_Brad]

Especially since their main source of music would have been LPs which have little of any musical content below 40Hz anyway.

Not intended content, at least. But you did correctly mention "musical" content…

 

[MaxwellsEq]

Not intended content, at least. But you did correctly mention "musical" content…

View attachment 425520

I wouldn't buy a phono preamplifier that didn't have a High Pass filter option. Once you get near the 10 to 15Hz maelstrom of resonances, you are simply wasting amplifier power.

 

[mhardy6647]

I wouldn't buy a phono preamplifier that didn't have a High Pass filter option. Once you get near the 10 to 15Hz maelstrom of resonances, you are simply wasting amplifier power.

And, in some cases, torturing loudspeakers.