Wow! One would think that would hit the news but nope.The FTC has ruled on this and they side with me and 548 other people who bothered to comment or provide submissions to their requests.
The updated Rule requires any and all amplifiers being advertised for sale in the US from next month (August) who wish to advertise a power output of any value above 2W to rate them in accordance with the regulations or suffer the consequences.
Does this "all frequency same level gain, phase and deliverable voltage" have a real world audible use or is just for your own peace of mind?Not misleading at all.
Amplifiers must be linear devices, which means they treat ALL frequencies with the same level of gain, phase and deliverable voltage and current (power) across their rated bandwidth and rated power.
No excuses.
It's part of a definition of a good amplifier that I think is valid as far as it goes, but it's also not strictly required to achieve good sound quality in practice.Does this "all frequency same level gain, phase and deliverable voltage" have a real world audible use or is just for your own peace of mind?
What a coincidence that you mention Neumann in this thread which deals partly with different amplifier classes and partly with the level of SINAD that can be suitable, acceptable on an amplifier.-50dB to -60dB THD for 5Khz and above @ 90dB SPL from Neumann's own data for the KH120 II.
So, purely academic.
My definition of a good amplifier (or any other part of the audio chain) is that it's objectively below a threshold (which is not nearly as strict as many here tend to put it) where humans don't really hear the distortion, noise etc, below that I don't really care and will prioritize other things instead.It's part of a definition of a good amplifier that I think is valid as far as it goes, but it's also not strictly required to achieve good sound quality in practice.
Edit:
But if I had to choose, I would still choose a used class AB amplifier. For example, the NAD C 320BEE with its 67 watts that I mentioned in a post earlier. A good amp with SINAD around 95 (the NADs power amp alone at 5 watt), even in the higher frequencies. But that choice is mostly because the physical size doesn't bother me plus a NAD C 320BEE can be bought and sold for around $120 where I live. A safe card, so to speak, as long as it doesn't break, but it's always a risk you take if you buy used.![]()
I'm interested in how this is going to play out; for example, will it be adopted more widely and whether consumers will be made aware. Usually manufacturers find a way round it by inventing their own metrics ("music watts", or "ultrafast power").The FTC has ruled on this and they side with me and 548 other people who bothered to comment or provide submissions to their requests.
The updated Rule requires any and all amplifiers being advertised for sale in the US from next month (August) who wish to advertise a power output of any value above 2W to rate them in accordance with the regulations or suffer the consequences.
Those regulations provide for THD+N from 250mW to rated power and across the entire audio bandwidth (20Hz-20kHz). So, whether you think HF THD+N is relevant or not doesn't matter one iota. Class D amplifiers will have to be advertised and rated the same way as all other amplifiers. They will have to be honest for once. If their amplifiers descend into noise at the low end- bad luck. If their THD+N skyrockets at high frequencies, bad luck- rate them properly.
And there's plenty of other classes, brands and designs of amplifiers that have been rorting consumers through false and misleading specifications. It's not just Class D, but a few major players have been egregious in this regard.
Get your wife a nice toe manicure, hands too and also the hair needs a touch-up and you'll be fine.I regret selling my NAD C320BEE. It was my first real audio purchase. I babied the thing, even replaced the connectors and power cable with expensive audiophile versions. (Forums were so much worse back then.) Funny enough one of the last favors it did for me was to open my mind up to an objective perspective. It had served as the center of my second system after I replaced it with a monstrous Nelson Pass associated Class A 50W Forte Model 4. I always sort of hated the latter. The size, the insane amount of HEAT it produced, the cost of running it. But it had "prestige." (I do not miss those types of amplifiers AT ALL. Good riddance! For fun, I just got a toy SMSL A50 PRO mini class D amp and in all honesty I would pay you $500 to use it over that Forte.) Once I started learning about measurements it was time to sell the Forte as its resale value was at its peak. I used it one last time and then I decided to compare it to the NAD. It wasn't a proper comparison, no output matching, not real AB testing, but man, I did not hear any difference. My mind was trying so hard to find it. I didn't fully believe myself until later when Amir reviewed it and it was all there for me to see. I have so much audio gear now but I still want to get myself another one. My wife is going to kill me.
We need a thread "Shouldn't we downgrade the 20-20 audible range ?!"I'm interested in how this is going to play out; for example, will it be adopted more widely and whether consumers will be made aware. Usually manufacturers find a way round it by inventing their own metrics ("music watts", or "ultrafast power").
Since I probably can't easily detect the 2nd harmonic distortion artefacts of an 8kHz fundamental, I don't care as much about distortion at high frequency, but I care more about noise.
No to the thread and no to the downgrade.We need a thread "Shouldn't we downgrade the 20-20 audible range ?!"![]()
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And no to a thread downgrade (knowledgeable people arguing from a different viewpoint)
Instead we should try to underline the difference between measured performance on a test bench, specification standards and minimum required performance for music reproduction and underline what matters for human hearing and transducers response to such applied power levels.
Both @restorer-john and @staticV3 are 'right' and make valid points (IMO) from their respective standpoints.
I am pretty sure John never listens to music with 200W of power through his tweeters and enjoys that music and static knows what a good measuring amp looks like on a test bench.
So if the price of lower but not audible distortion above 5khz is a more expensive, bigger size, warmer, less effective amplifier then I'm not interested whatsoever. But if there is a valid argument for audibly lower distortion then I'm curious. But tbh since my other amplifier is broken atm I'm running a very cheap TPA3118 amp with a SINAD of around 65dB and I think it sounds more than fine across the whole range so I don't think I actually care![]()
You mention 80dB.The general information is people don't hear distortion if it is kept below -60 db (.1%). And that is with test tones in the range we are most sensitive. It is worse at other frequencies and worse again with music itself. I really wouldn't want to relax to less than -60 db plus the amp is only one part, so for safety -80 db (.01%) is too easy with modern tech. I would say beyond that, it likely doesn't matter, but who would complain about less distortion? None of this is anything most of you don't already know.