Well apparently I do have super hearing! I often hear things that happened far away and usually a while ago!
As to ferrites decreasing fidelity, the route I looked at was what a DC offset in the AC power line that could cause a line filter ferrite core to saturate, producing an effectively asymmetric clipping on the AC primary of the power supply transformer. That in turn would have some higher frequency hash that would appear as an increase in the noise floor.
As to ferrites decreasing fidelity, the route I looked at was what a DC offset in the AC power line that could cause a line filter ferrite core to saturate, producing an effectively asymmetric clipping on the AC primary of the power supply transformer. That in turn would have some higher frequency hash that would appear as an increase in the noise floor.
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My bad! A knowledgable friend informs me the dog is clearly smarter. She cleans up after it not the other way around!
Interesting theory and possible mechanism for AC powered equipment, however IME I find just now that clamping a ferrite around headphone cable connected to cell phone (battery powered and floating) playing Youtube dialogue causes change in sound with change in mids and empahasis on essing and 'hardening' of the overall sound, also sounding as though recording has been 'sped up' slightly.
On first impression they may be interpreted as improvement (increased 'detail' due to HF emphasis) but long term I find them fatiguing and unnatural and removal sounds preferable to my ears.
Bruno Putzeys has offered an explanation of hysteresis distortion, a type of memory-effect IMD, that could be what you are hearing. At least, that's what he says about iron core output inductors for class D power amps. Interesting that the particular distortion does not show up using sine wave testing 😱
Bruno did say: "... what came out of tests on iron parts in loudspeakers was that hysteresis has a long term memory so you can get intermodulation between things that happen now and things that happened 10 minutes ago. With music this distortion sounds like half correlated noise..."
He went on to say, "...We have a strong suspicion here that the most audible distortion in typical class D amplifiers may very well be that."
When asked by his partner, Lars, "...Wouldn’t you say that speakers with drive units that explicitly tackle hysteresis distortion like ours and like DALI’s, are much more revealing of the differences between class D amps?" Bruno responded, "...I’d say so."
Doubtful anyone would want to push the audibility thing too far though, lest they find themselves having to spend all their time on human subject testing to find thresholds. Otherwise they would find themselves accused of snake oil blah, blah. blah. We all know how it goes.
He went on to say, "...We have a strong suspicion here that the most audible distortion in typical class D amplifiers may very well be that."
When asked by his partner, Lars, "...Wouldn’t you say that speakers with drive units that explicitly tackle hysteresis distortion like ours and like DALI’s, are much more revealing of the differences between class D amps?" Bruno responded, "...I’d say so."
Doubtful anyone would want to push the audibility thing too far though, lest they find themselves having to spend all their time on human subject testing to find thresholds. Otherwise they would find themselves accused of snake oil blah, blah. blah. We all know how it goes.
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OK, gag me with a spoon... Cant wait to read the explanation on how their drive units "explicitly tackle" some long-term "hysteresis distortion" supposedly within a tiny inductor operating at 100's of kHertz...
I think I'll go waste my oxygen allocation enjoying some music and remain blissfully ignorant as to whether some barely perceptible, unmeasurable anomaly I think I heard was the result of something that occurred 15 minutes ago (setting things up within my amp's output inductors...) ...and not simply a transient artifact in the original recording of this song playing now, versus something physically carrying over from that song playing previously.
What human imagination can cook up never ceases to amaze me. I suppose they have a sequence of source material that consistently makes this happen and is repeatable in their own and other's listening labs.
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BTW here is the whole article without edited highlights to try and make someones point!
PURIFI Audio and the Audiophile Style reader's Q&A with Lars Risbo & Bruno Putzeys
PURIFI Audio and the Audiophile Style reader's Q&A with Lars Risbo & Bruno Putzeys
You seem to misunderstand what was being said. Bruno and Lars make speakers and class-D power amps. Their speakers are very low distortion, and to get them that way one of the things they had to do was reduce the speaker's hysteresis distortion at audio frequencies.
Armed with that experience, they then think they found hysteresis distortion in the output inductor of their class-D power amps. The are using super fast switching transistors now, so they are able to use an air core inductor at the higher switching freqeuncies (unlike Bruno's last generation of class D amps).
Understanding all that, they think (1) class-D amps are audibly different, (2) they think using a low distortion speaker makes it easier to hear the audible differences between class-D amps, and (3) they think the iron core output inductor found in most class-D amps (like in Bruno's other amp company) is probably responsible for most of the audible distortion produced by the amp.
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The only point was that if ferrites are reported to have audible distortion effects that don't show up in sine wave tests, its possible that there is some real distortion. No need to immediately jump to the conclusion that the person reporting an audible effect is crazy, a liar, or a snake oil salesman. There may actually be a plausible scientific explanation. I only raise the point because I don't like to see innocent people maligned.
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Mark, I guess you are referring to this
This Thing We Have About Hysteresis Distortion - PURIFI
There, Bruno showed with animations what happens with minor loops inside the major loop. The intriguing part was the asymmetric (about the origin) minor loop. Not something unexplored or unexplained up to now.
The ‘memory effect’ has in classic texts been given the name retentivity (the ability to retain magnetization after the removal of the magnetizing force). You have to apply an opposing magnetizing field H to nullify the flux density B (that’s called coersivity).
This is why assymetric minor loops can be generated .
Check it (*) when you apply on a transformer a sinusoidal signal with some harmonic distortion added (like Bruno did). Fundamental frequency component will generate the major loop. Harmonic component will generate the assymetric loop fixed in place (constant phase btn main and harmonic frequency component).
When applying music -superimposed sinusoidal signals of different frequency and amplitude- hysteresis loop is juggled as there are many assymetric loops not fixed in place but running along some major loop due to varying relative phase.
Bruno (in the above article) has not written that memory effect does not show up using sine wave excitation.
George
(*)
https://www.diyaudio.com/forums/att...s/120802d1228077568-curve-tracer-dscn6128-jpg
Plotting Magnetization Curves
Yes they intermodulate. No **** sherlock. We accepted years ago that sine wave tests are not more than a wet finger. You get IMD. Bruno uses heroic amounts of NFB to sort that.
No need to get rude.
Speculation is all you have. Why not wait till there is a conclusive evidence.
What was said.
IMO a poor choice of words, there is technically no intermodulation, they are describing a magnetic domain relaxation going on akin to Barkhausen noise.
