Hopefully @amirm will correct what I thought I understood!I don’t think he said that at all.
Hopefully @amirm will correct what I thought I understood!I don’t think he said that at all.
We use psychoacoustics so that we don't have to run out and perform double blind tests every minute. I explained why perceptual masking does not help you here. You can't counter that with "I don't think so" and demand a double-blind test.
Look at this graph:
That high distortion goes way down to 20 Hz as it should since the circuit is operating well outside of its design metrics (due to amp clipping). So -now take that 1 kHz tone and move it down in frequency such that those harmonics land in 2 to 5 kHz. Then look at Fletcher-Munson curves:
See how the thresholds for hearing anything there is actually negative SPL? And therefore way way lower than the harmonics we are seeing here?
Those harmonics keep going higher where the amplitude of content is very low. It mixes with them and potentially makes them higher pitched.
So your skepticism is not based what we have measured and what we know about science of what we hear.
There is no such thing as "audibility of 0.25% distortion." THD+N is not instructive that way because it is a single number. This is why I show the spectrum. You use that to perform the analysis that I showed you to determine audibility.I’m aware of Fletcher-Munson type curves. I’m not aware of any research that shows audibility of 0.25% distortion.
So you know then that the range of human hearing range should from 0-120 dB?
There is no such thing as "audibility of 0.25% distortion." THD+N is not instructive that way because it is a single number. This is why I show the spectrum. You use that to perform the analysis that I showed you to determine audibility.
I was going to walk him through it, @amirm. I'll first confirm his understanding of F-M. Then I'll introduce him to even/odd order harmonics. Next, I'll convert 0.25% THD to -54 dB. Then I will show him what that means against a primary frequency (or series of frequencies) played at reference levels. I will then explain the limits of masking. Next I will superimpose spls on the F-M curves.
I was going to walk him through it, @amirm. I'll first confirm his understanding of F-M. Then I'll introduce him to even/odd order harmonics. Next, I'll convert 0.25% THD to -54 dB. Then I will show him what that means against a primary frequency (or series of frequencies) played at reference levels. I will then explain the limits of masking. Next I will superimpose spls on the F-M curves.
He'll sense the trap when I get to the part about reference levels and start to deny the validity of science, his super human hearing, the brain's marvellous and medically unexplained ability to be a notch filter into to Tetrahertz range, etc.
He'll then say I'm insulting him, trying to embarrass him, and am a rude and ignorant twit. He'll be joined by other surrealists, subjectivists and anyone who has taken exception with anything I've ever said (including grammatical errors and typos).
Having mapped out all of that, what do you say about leaving him to figure it out on his own?
@Theriverlethe: You're on your own.
I was going to walk him through it, @amirm. I'll first confirm his understanding of F-M. Then I'll introduce him to even/odd order harmonics. Next, I'll convert 0.25% THD to -54 dB. Then I will show him what that means against a primary frequency (or series of frequencies) played at reference levels. I will then explain the limits of masking. Next I will superimpose spls on the F-M curves.
He'll sense the trap when I get to the part about reference levels and start to deny the validity of science, his super human hearing, the brain's marvellous and medically unexplained ability to be a notch filter into to Tetrahertz range, etc.
He'll then say I'm insulting him, trying to embarrass him, and am a rude and ignorant twit. He'll be joined by other surrealists, subjectivists and anyone who has taken exception with anything I've ever said (including grammatical errors and typos).
Having mapped out all of that, what do you say about leaving him to figure it out on his own?
@Theriverlethe: You're on your own.
With THX reference peaks at 105dB, that puts the third harmonic at 53dB, below the noise floor of most rooms. Of course, noise below the room’s noise floor could still be audible, were it not for the fundamental peak more than 32 times louder.
No room has "53 dB" of noise. That is what a dumb SPL meter shows. The actual noise in the room is heavily biased to low frequencies because those are the ones that walls don't block easily. In mid-levels where our hearing is most sensitive, many rooms come close to threshold of hearing. See this article I wrote for WSR magazine and please don't keep repeating this myth: https://www.audiosciencereview.com/forum/index.php?threads/dynamic-range-how-quiet-is-quiet.14/With THX reference peaks at 105dB, that puts the third harmonic at 53dB, below the noise floor of most rooms.
And btw, @Theriverlethe, you're presenting an incorrect view of the sound levels too. It's not 105 dB peak, it's 85 dB that you should be using. That's the spl that is predominant (mode or mean) when listening at reference levels.
It would very useful if someone did this explanation that fit together X different metrics - absolute and ratios - thrown about into a coherent, self-explanatory description and relate it to audibility. Not to spite someone but I suspect a vast majority of the readers here don’t have a clue of what all this means even if they agree with the conclusion.
Such a thing, placed in a FAQ or a community Wiki could be very useful to newcomers as well.
Full amplitude content is quite common and has been since loudness wars started. It is routine to get content at 0 dB.Yes, but the clipping only comes into play with a full scale signal like Amir’s test tone.
I don't think he is trolling. He has the unit and is defending it.Maybe. But for the moment it seems to me that @Theriverlethe is trolling. Why do I think this?
I don't think he is trolling. He has the unit and is defending it.
Gives us a chance to dig into the topic a bit so not entirely bad.Oh... another one of "those".
This is as tedious as trolling. Ha ha.
Gives us a chance to dig into the topic a bit so not entirely bad.