Feedback loops I am familiar with, that's a common problem I dealt with performing music. That is distinct from what I'm talking about.
Typically, a feedback loop in music situations is due to a resonance at a particular frequency and can therefore be dealt with by a high Q notch filter. Sometimes though it’s several resonances, which can require several notch filters (or another solution) and this type of feedback loop can sound uncannily like a scream, especially when it causes still more tones/freqs due to clipping distortion and IMD, as the amp, speakers, tape or digital recorder approach their limits/saturation.
You are right about my experience with audio oddities/errors, it is certainly limited. That's a part of the reason why I don't blindly believe every allegation of captured EVP because it's possibly coincidental.
I’ve come across some real oddities over the course of nearly 30 years working in film/TV sound. Someone apparently whistling Yankee Doodle Dandy over a take, and someone saying “are you riding a donkey?” over another take, which couldn’t have been coincidence because it occurred twice, on different days. No one had said or whistled that, no one heard it at the time, it only occurred on a certain channel (or channels) but was completely non-existent on others and pretty much everyone who heard it on the recording later recognised it, without being told before hand what to listen for. It wasn’t pareidolia, the freqs were identifiable in a spectrogram and these are just two of numerous examples I’ve experienced over the years, both of which were explained, though only after a considerable time in the latter example.
But I find it difficult to believe that all of it is pareidolia given how much circumstantial evidence there is about how much we have yet to uncover in the hard and soft sciences …
Two points: Firstly, it’s not all pareidolia, the two examples above weren’t and there are numerous other examples that weren’t, although there are also other numerous examples where that is the explanation, for example the old reversing of various recordings and hearing messages about the devil was a popularly famous example a few decades ago. In addition to pareidolia (and the two examples above, which were not a quirk of human perception), there are numerous other ways that human perception can be fooled, some of which have again been routine procedure for Dialogue (and other film sound) Editors for many decades, some of the tricks we can play with phonemes and other sounds for example.
Secondly, I’m not sure exactly what you mean by “
hard and soft sciences” but it’s a quite common trope for audiophiles to claim that science doesn’t know everything and/or that it’s constantly evolving. This is true of course but only in certain areas. At the cutting edge of mathematics and physics we don’t know everything, science in these areas is constantly evolving and there is still more to uncover but what many audiophiles don’t seem to understand (largely because they simply don’t know and have been misinformed) is that we’re not dealing with the cutting edge of physics or mathematics, we’re dealing with good old classical physics, effectively put to bed ~130 years ago and maths from mostly ~200 years ago, although one could argue that Shannon’s maths ~75 years ago was at least somewhat innovative. There really is nothing ”
we have yet to uncover” but again, even if there were, then we cannot record or reproduce it anyway. Audiophiles often like to see themselves as ”special”, an especially discerning community, specifically concerned with a far higher class of consumer equipment than the average consumer. In reality, they are just a very tiny group within the telecoms industry, which has had, arguably, more R&D resources thrown at it (both in terms of money and scientists/researchers/engineers) than any other industry and, for well over a century. So the chances of coming across some completely new, previously undetected, un-hinted at audio/sound phenomena is minuscule, at most! The exception to all the above is the field of psychoacoustics, where we definitely don’t know everything, it is still evolving and there almost certainly is still more to uncover but that
ALL pertains to how our brain interprets/perceives/evaluates/responds to sound, not to the sound itself!
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