Excerpt from Clark Johnsen's landmark article on Absolute Polarity in Issue 1 Positive Feedback Online:
"Oh, the Wood Effect. Discovered by Charles Wood at the Defense Research Laboratory in 1957, it was first reported in 1962 in the Journal of the Acoustical Society of America. "Wood used as a signal a sinusoid partially clipped during half of each cycle. The resulting sound had a different timbre when the flat-topped portion was presented to the ear as a rarefaction, than it did when leads were reversed and the flat-topped portion was presented as a compression." There you have it, ladies and gentlemen: An asymmetric sinusoidal signal, presented those two dissimilar ways, with no other distortion, was proven to sound very different each way. Let’s see, what else in the sonic realm generates asymmetric signals? Well, ta da! That would be musical instruments! Which explains how polarity permeates our entire audio world, albeit through negligence, because we hear normal and inverted polarity (more accurately, compression and rarefaction) so very dissimilarly, ,yet rarely are they differentiated by us in playback.
The abstract to The Wood Effect says it best: "Masked by random combination with other distortions in the music reproduction chain, an unsuspected major contributor has lain hidden: Aural sensitivity to ‘phase inversion’ — the Wood Effect."
"Music normally creates compression waves. Electronics, however, often invert that natural, positive polarity to unnatural, negative rarefaction, thus diminishing physical and aesthetic impact. The term Absolute Polarity uniquely describes the correct arrival to the ear of wavefronts from loudspeakers, with respect to actual musical instruments."
"Wrong polarity, when isolated, is obvious to everyone. Its present neglect results from habitual disregard for phase response, especially in loudspeakers."
But as to why I’m on the case again, there are problems in those Ultimate Audio articles by Mrs. Herron and Fredell—and elsewhere too, notably in an e-zine, in a piece authored by Doug Blackburn, outstanding for its wrong-headedness. These writers (and many others, too) confuse small-case polarity with Absolute Polarity. Also, they use "polarity" interchangeably with "phase." Phase could mean any degree, while polarity denotes precisely the 180° condition. Third, they all seem to think that the Absolute inheres in recorded media, whereas in truth it occurs only at the final impingement point: your ear. To quote Mr. Herron: "Absolute polarity can be lost... and again restored in many places in the recording and playback chain." No, Keith! You mean, simply, polarity. And not "lost," either: polarity never disappears, it only reverses itself, time and again."
"Oh, the Wood Effect. Discovered by Charles Wood at the Defense Research Laboratory in 1957, it was first reported in 1962 in the Journal of the Acoustical Society of America. "Wood used as a signal a sinusoid partially clipped during half of each cycle. The resulting sound had a different timbre when the flat-topped portion was presented to the ear as a rarefaction, than it did when leads were reversed and the flat-topped portion was presented as a compression." There you have it, ladies and gentlemen: An asymmetric sinusoidal signal, presented those two dissimilar ways, with no other distortion, was proven to sound very different each way. Let’s see, what else in the sonic realm generates asymmetric signals? Well, ta da! That would be musical instruments! Which explains how polarity permeates our entire audio world, albeit through negligence, because we hear normal and inverted polarity (more accurately, compression and rarefaction) so very dissimilarly, ,yet rarely are they differentiated by us in playback.
The abstract to The Wood Effect says it best: "Masked by random combination with other distortions in the music reproduction chain, an unsuspected major contributor has lain hidden: Aural sensitivity to ‘phase inversion’ — the Wood Effect."
"Music normally creates compression waves. Electronics, however, often invert that natural, positive polarity to unnatural, negative rarefaction, thus diminishing physical and aesthetic impact. The term Absolute Polarity uniquely describes the correct arrival to the ear of wavefronts from loudspeakers, with respect to actual musical instruments."
"Wrong polarity, when isolated, is obvious to everyone. Its present neglect results from habitual disregard for phase response, especially in loudspeakers."
But as to why I’m on the case again, there are problems in those Ultimate Audio articles by Mrs. Herron and Fredell—and elsewhere too, notably in an e-zine, in a piece authored by Doug Blackburn, outstanding for its wrong-headedness. These writers (and many others, too) confuse small-case polarity with Absolute Polarity. Also, they use "polarity" interchangeably with "phase." Phase could mean any degree, while polarity denotes precisely the 180° condition. Third, they all seem to think that the Absolute inheres in recorded media, whereas in truth it occurs only at the final impingement point: your ear. To quote Mr. Herron: "Absolute polarity can be lost... and again restored in many places in the recording and playback chain." No, Keith! You mean, simply, polarity. And not "lost," either: polarity never disappears, it only reverses itself, time and again."