Stuck there are we X? Where are the studies that correlate these too what we hear? The only one i've seen says it is meaningless. And 45 years of experience.
Distrotion is important.Measures aswe dothem know is avery poor indicator of what that is.
You need low information loss to get there. But your measures do not tell you much about that.
It's everywhere.
Sort of. It is bigger than that. It has been shown the humans can hear signalwell into the noise.
Not really what we are talking about.
Equation? At this point it is a concept, a way of thinking. At some point i truly hopd it will be quantifible. But we have a lot tolearn about measuring audio. And probably even more important what the ear/brain needs to create an enjoyable illusion.
dave
Not hard to find research on the topic of HD audibility.
http://www.almainternational.org/assets/PapersLibrary/2013WinterSymposium/measurement%20of%20harmonic%20distortion%20audibility-listen%20inc-alma%20ws%202013.pdf
Also see this very good paper and references therein:
http://www.bksv.com/doc/bo0385.pdf
Perceived distortion is affected by frequency it occurs at (400 Hz and above is more important) and duration of the signal. But certainly it is audible and makes a difference.
It is audible otherwise manufacturers would not use so many things to make the drivers lower distortion - like shorting rings.
http://www.almainternational.org/assets/PapersLibrary/2013WinterSymposium/measurement%20of%20harmonic%20distortion%20audibility-listen%20inc-alma%20ws%202013.pdf
Also see this very good paper and references therein:
http://www.bksv.com/doc/bo0385.pdf
Perceived distortion is affected by frequency it occurs at (400 Hz and above is more important) and duration of the signal. But certainly it is audible and makes a difference.
It is audible otherwise manufacturers would not use so many things to make the drivers lower distortion - like shorting rings.
Some interesting reading. Having more of a history on visual side of things [photography and HT], I can see a lot of parallels in specific terms being used here.
I was intrigued with Dave's DDR... to me this is a measure of 'Contrast'... Play a twin tone [or two instruments]. Keep the Primary at a constant level and drop the level of the secondary. Measure or listen, until the secondary is lost amongst the harmonics of the primary [or can't be heard by ear], the difference is the your personal/measured range of contrast ... Perceivable/measurable contrast, DDR.
But that'd be the highest level of contrast in a black against white way, music isn't that simple 🙂
Just a thought...
Paul
I was intrigued with Dave's DDR... to me this is a measure of 'Contrast'... Play a twin tone [or two instruments]. Keep the Primary at a constant level and drop the level of the secondary. Measure or listen, until the secondary is lost amongst the harmonics of the primary [or can't be heard by ear], the difference is the your personal/measured range of contrast ... Perceivable/measurable contrast, DDR.
But that'd be the highest level of contrast in a black against white way, music isn't that simple 🙂
Just a thought...
Paul
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Lower distortion is important. Just that how we measure it is not that useful in determining what things sound like.
dave
1st line slide 2 "Conventional distortion measurements such as THD do not show reliable correlation to the ear’s perception"
Exactly what i have been saying. They are exploring other ways to measure that correclate with what/how we hear.
A typically well written piece by B&K (a company selling measure equipment) on how traditional distortion measures work.
dave
Planet10,
I agree THD is not the best but I am referring to looking at other harmonics and the paper does use other orders of harmonic distortion for their neural network based algorithm to derive the Perceptual Total Harmonic Algorithm (PTHD). They are not saying harmonic distortion is not useful. This is exactly the point of the research - that there are other ways to define distortion.
I agree THD is not the best but I am referring to looking at other harmonics and the paper does use other orders of harmonic distortion for their neural network based algorithm to derive the Perceptual Total Harmonic Algorithm (PTHD). They are not saying harmonic distortion is not useful. This is exactly the point of the research - that there are other ways to define distortion.
They can be a useful design tool, but far to may people put way too much faith in what they represent.
Being an FFT one also needs to take care of the resolution limitations.
dave
But you talk as if it is.
Distortion is distortion. What we measure is a small subset. This paper tries to take what we do measure already and run it thru an algoritm that attempts to present it in a way that gives them some correlation to perception because as it comes out of the box it is not.
dave
I seem to recall Toole goes into this a bit in his recent book.
THD? Worthless. As a summed total its value is roughly equivalent to the square root of Jack. Individual distortion levels = much more useful, but they don't tell you everything. Wish they did, life would be a whole lot easier.
THD? Worthless. As a summed total its value is roughly equivalent to the square root of Jack. Individual distortion levels = much more useful, but they don't tell you everything. Wish they did, life would be a whole lot easier.
If a speaker had a THD of Jack, I think it would be a better speaker than one with THD greater than Jack.
Irrelevant. The point I made is that a summed total THD tells you nothing of practical use. Independent values for xyz orders can tell you something you might actually want to know, but not all.
My point is if THD was Jack or zero, by definition, all n'th harmonics are zero as well - you have a pure tone output for a given sine input. If nonzero then having the n'th order harmonics, preferably up to 5 are useful. But zero distortion is better than finite distortion.
I'm aware of what your point is, and it remains irrelevant to what I said, which was not about levels, but the fact that a summed THD number tells you nothing useful. It's about the practical utility of the measurement, not distortion or the lack thereof. Individual levels per order can tell you something of value.
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I'm scratching my head here.....The fact that you have a summed thd usually means that you have visibility of the individual levels......or am I missing something??
is there a piece of software/kit that just shows the total??
is this with respect to having measured the amplifiers thd immediately beforehand to isolate it's contribution...I too, may have missed the point.🙂
That's the problem. Some do lump them together in sum unfortunately, sans the individual levels which are actually useful. Or a total is simply cited, without reference to specifics.
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