I really do not think so. Flat freq + <2% THD are very simple conditions, oversimplified. Regardless we may discuss THD profile (like 0.5% THD completely created by crossover distortion - very audible!), please do not omit noise profile, S/N and noise spectrum, PSR + interference rejection - these are key parameters. Flat freq response and THD low enough is easily achievable.
I'm not sure whether this is a serious question or just a debating point. If a serious question then your knowledge of science in general and electronics in particular is even more limited than I imagined. If a debating point then I can't quite work out what your aim is in asking it.yldouright said:
Page numbers are not a good way of referring to previous posts, as they depend on reader settings. You need to give post numbers, as these are unique.
Now you appear to be asking for perfection again.
I would regard it as an honour to join them. I may reciprocate.
I think it is time I stopped feeding.
This is a disaster of a question, the only answer is they should be emphasizing every parameter with 100% of the effort.
The idea that amplifier designers should eschew certain parameters that they currently don't in order to satisfy the ego maniacal claims of audiophile ghost whispering would destroy the industry.
The standard power rating considers a sine wave, mainly because of repeatability.
And being steady, by definition it does not have dynamic range.
Real music does, of course, I hope you don't ignore that important fact.
So to compare transparent amps , music must be played at such a level that we do not meet clipping.
I already suggested a couple clippers for those who want to compare such things.
No, in theory they are the same.
But since *just* reaching clipping opens a BIG can of worms, I'd rather add a dB or two of extra distance/padding/safety_margin/you name it.
Good Engineering practice.
By the way, do you consider good practice airplanes reaching their destination airport with just a spoonful of fuel remaining in the tanks?
Well, same thing here.
A much better analogy is this, http://www.diyaudio.com/forums/loun...lifier-general-discussion-82.html#post4038279; IOW, the audio can genuinely do what it claims to do ...
Of course, the big can worms opened is that power supplies are usually pretty dreadful under dynamic conditions; the voltage rail becomes a glorious, very messy echo of the input signal at higher power levels - so there is every chance that transient clipping will occur, because the rail has sagged and is modulating too greatly.
IME, if extremely stiff supplies are used, then transient clipping is undetectable - the audible artifact is so short in duration that it is not heard ... why normally "clipping" is heard to be so bad, is because the power supply has virtually collapsed in its ability to maintain any semblence of a decent voltage rail ...
Of course, the big can worms opened is that power supplies are usually pretty dreadful under dynamic conditions; the voltage rail becomes a glorious, very messy echo of the input signal at higher power levels - so there is every chance that transient clipping will occur, because the rail has sagged and is modulating too greatly.
IME, if extremely stiff supplies are used, then transient clipping is undetectable - the audible artifact is so short in duration that it is not heard ... why normally "clipping" is heard to be so bad, is because the power supply has virtually collapsed in its ability to maintain any semblence of a decent voltage rail ...
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Just a small, tiny tin of worms for today:
Where does clipping start?
The makers of my power amps define the onset of clipping as when THD exceeds -70dB (0.03%), the people who made my phono pre when THD+N exceeds -80dB (0.01%) while most HiFi manufacturers seem to use -40dB (1%).
Clearly some pro audio manufacturers set very much more stringent limits (I use pro amps and the phono pre was made for radio stations) then HiFi and tube amps under those conditions would be pretty much regarded as clipping at all times.
Mildly confused here...
I am not a lawyer, but I'd say the moment distortion starts going up because of an inability to deliver more voltage.
I've always thought all amplifiers should have way more features to indicate internal behavior on the front panels.
These guys do it right: https://www.youtube.com/watch?v=yPLOMUHaR6U
https://www.youtube.com/watch?v=B6h_3hCu_0o
Just crank down that voltage until it's within what the speaker can handle and be done with it. This is 2014, and we're still in a place where only a few pro amps have decent features...probably because audio guys spend so much time arguing about cromulence. Clipping should not be something that we worry about with modern technology.
This is the same as asking "at what forward voltage does a silicon diode turn on?". There isn't a 'correct' answer.Charles Darwin said:
A useful answer may be: the point at which THD doubles (or increases by some other specified ratio). Another useful answer may be: the point at which waveform clipping becomes visible on a scope (typically around 1%). Or how about: the point at which output compression causes power to drop by 10% below the expected power?
This is one of those questions where the answer will depend on why you are asking the question.
Just for myself and my measurements, I define it as a point when high harmonics in spectrum analysis start to raise suddenly. It is well below visible clipping and well below 1%. It may happen as soon as at 0.04%, e.g.
Thread temporarily closed for a clean up. Guys It is fine (and encouraged) to put forward opposing views. To question suppositions, and to generally try to enlighten people when you feel that they are missing something.
However please be mindful of the fact that not everyone shares your view, and some people no matter how much you put forward will ever accept it. In those cases the best thing to do is walk away.
Whilst you may find crapping up a thread amusing. It *IS* against the rules of this forum, and as such I would request that everyone who is not contributing serious arguments to the debate cease posting (once the thread has been re-opened).
If someone crapped on your thread, you wouldn't be happy. Do unto others as you would have them do unto you.
OK I have cleaned up the last few pages of posts. I deleted a LOT of posts. Yes some of them were funnny, but they were rules breaking. yldouright it has not escaped my attention that there is a possibility that this thread was started as a trolling activity, so don't think of this cleanup as a victory.
I would suggest that anyone who has got fed up should walk away.
Anyone who has decent arguments that they wish to put forward (from either side) please do so. Just don't expect that you are going to convert anyone to your way of thinking. Epiphanies do happen, but don't hold your breath (take that as a neutral statement aimed at both sides, because from where I am sitting it seems that there is closed mindedness happening regardless of viewpoint).
As Pano said earlier there was an opportunity presented in this thread, even if you don't agree with the OP's suppositions. I hope that those that are not interested in taking up that opportunity will let those that are do so.
Thread will now be reopened.
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Mostly curiosity.
Since I've done the Klippel test regarding audibility of (added) THD I find 1% too high.
Through my speakers I could hear added THD down to 0.5%. Below that I was guessing which may be due to my ears or my speakers, impossible to tell until I get hold of speakers which produce significantly less than 0.5% by themselves and that could well be a long, long wait! ;-)
The chances that my amps get anywhere near clipping are practically nil since I run my fairly efficient (91-95dB/1W/1m) active speakers with roughly 900W per channel.
So for the time being I guess I'll side with PMA on this one.
Clipping is never a problem for me- old farts don't like loud music, and I consider any speaker that wanders down into the sub-ohm impedance area has something wrong with its design (open to a rethink under certain dynamic conditions), so this should be pretty easy. Earlier I threw out some numbers- input and output subtracted and no difference greater than 0.01% with any music signal. I believe that is entirely achievable, actually has been for quite a while. Can anybody make a case that there is some artifact, harmonic or other defect within that limit that's audible?
I find the Sony Receiver example fascinating, because it is about the absolute limit (in my opinion) of the perfect test for both ABX testing and what we can fairly obviously hear openly. IF DBX testing shows a complete null, typically, then I would like to note it, by comparing this Sony to other higher priced stuff, like the Parasound A-21 power amp, and even the A-23. Maybe even measured improvements mean little or nothing. Worth a look.
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If I read you right, you're saying that peeking is the gold standard, and if you can't hear the difference using only your ears, then using only your ears is somehow discredited?
If you're saying the opposite (i.e., if you can't tell the difference just using your ears, then peeking is not giving you an accurate picture of actual sound differences), then we've made a lot of progress.
If you're saying the opposite (i.e., if you can't tell the difference just using your ears, then peeking is not giving you an accurate picture of actual sound differences), then we've made a lot of progress.
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