Listening test on math added harmonic distortion

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PMA

PMA

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pmacura.cz/audiopage.html
#1
Here is the new test, on harmonic distortion, that was added purely mathematically to the original data.

https://www.dropbox.com/s/joo2yic2swmwq1c/Test3.zip

There are 3 samples in the zip. One is original data and two are more or less distorted. The goal is to decide, by listening, which one is original, which is the more distorted one and which less distorted one and also please see Edit below.

This follows the discussion we have had with Frank here:

http://www.diyaudio.com/forums/ever...st-part-2-active-circuitry-5.html#post3809713
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Edit: the question about distortion is which file is subjectively more distorted one and which less distorted one, and also which is pure 3rd harmonic distorted and which is 'comb' distorted, see plots in the next post.
 
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#2
To make your task easier, here are the distortions used, re full scale. I am one ear and looking forward your listening results!
 

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#4
Thanks Tony, of course everyone please send results through PM and do not post file analysis here.

In the end, I will provide you with the difference file, which is similar to "distortion and noise with fundamental notched out". You will see, that ANY harmonic distortion, when isolated, is totally NASTY, there is nothing like euphonic distortion. Only marketing hype when they explain that 2nd order or 3rd order harmonic distortion is audibly innocuous.

I need to correct the labels I assigned to distorted files. Please write your impressions like this:

file X: .... original
file Y: .... 3H distortion (pure third harmonic)
file Y: .... multi distortion (the plot with many spectral lines hereabove)
 
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#7
I am not telling, for now. Please feel free to make any analysis, but do not post your results here, until the test is disclosed.

I can only tell that distortion is quickly reduced with decreasing amplitude, for the reason that the nonlinearity is generated by math equation, and distortion is zero at zero amplitude.
 
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#9
Distortions used expressed as THD.

"3H" is pure third harmonic distortion, THD = 1.08% re FS

"comb" are all odd harmonics up to 19th, THD = 0.36%

Which is worse for listeners? Which is more tolerable? Your answers, by now, are extremely interesting! 😉
And some of you have very good ears. But only some. Some like it distorted 😉
 

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#10
PMA said:
.You will see, that ANY harmonic distortion, when isolated, is totally NASTY, there is nothing like euphonic distortion. Only marketing hype when they explain that 2nd order or 3rd order harmonic distortion is audibly innocuous.
Click to expand...

Only in isolation right? But a tube amp does not deliver h.d in isolation...

G0bble



Sent from my GT-N7000 using Tapatalk
 
#14
PMA said:
It is quite individual if the people find listening with distortion bad or not. Some have very good abilities to hear it and to tell the difference.

As a hint, here is the difference (distortion) between two of the files in this test, in a sound file:

https://www.dropbox.com/s/wd005qj07mfjizq/harmdist.zip
Click to expand...

Thanks I will do a listening test today.

But your statement leads to the question- what exactly are we assessing then via listening tests? The distribution of individuals with good hearing versus bad, who can tell the difference, or evidence that is statistically proven that h.d is always bad? How can the latter be concluded if the former variable is always present?

G0bble

Sent from my GT-N7000 using Tapatalk
 
#17
Gobble said:
But your statement leads to the question- what exactly are we assessing then via listening tests? The distribution of individuals with good hearing versus bad, who can tell the difference, or evidence that is statistically proven that h.d is always bad? How can the latter be concluded if the former variable is always present?
Click to expand...

I think first and foremost we are determining whether there are some individuals who can pick out the distortion, and from what Pavel has said it would appear that there are some. We will probably also find that some people can't (which won't really be a surprise).

It may be interesting to know the proportion of those that can to those that can't as well, as that may explain some of the religious wars over what is audible and what is not 😉

I don't think personally that this test is about proving that distortion sounds bad. I said to Pavel in my PM (without giving anything away) That any one of those tracks given to me to listen too in the abscence of the others, and I would have commented that it was an excellent quality recording, and I would not have picked anything wrong with it. But I do think that I can hear a difference between them, when compared one against the other.

Tony.
 
#19
wintermute said:
I don't think personally that this test is about proving that distortion sounds bad. I said to Pavel in my PM (without giving anything away) That any one of those tracks given to me to listen too in the absence of the others, and I would have commented that it was an excellent quality recording, and I would not have picked anything wrong with it. But I do think that I can hear a difference between them, when compared one against the other.

Tony.
Click to expand...

Thanks for your very good comment, Tony. That's how it is and I am very happy to read such observations.
 
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