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diyAudio Member
Join Date: Dec 2003
Location: The Wilds Of Canada
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The human ear works as a 'diode' and only hears the leading edge of a given note. perhaps, if you played withthe DUTY CYCLE of the given sqare waves, the percieved answer may alter itself in some manner, compared to the original observations.
Also, the ear is timing and transient sensitive, which should be a logical extrapolation (follow the logic trail) of the statement that the ear works as a diode. This means, harmonics, timing (time related components surrounding the transient information) and amplitiue of the transient components are critical for human Observation.
If the 10% and the 90% points of the square wave (as normally considered) are cleaned up, via a small dose of inductance, the answer may pop out in a more clear fashion.
The fact that the human ear is capable of resolving transient information down to less than 100,000th of a second (timing issues, not frequency) is interesting. This is due to the timing of arrival of signals between each ear for spatial recognition of information, at the very least, and is a known human skill and phenomena,
This means, clocking of digital systems and the like, due to nyquist, must exceend 225khz sampling in extreme accuracy, to meet the minimum requirement for exceeding human resolving capacites, as recognized ---at this time---. Who knows, that figure may have to be revises YET AGAIN....and again..as it has been over the years.
I suspect you are hearing simple negative or postive edges of the given waveform, and the brain 'mixes up' the leading edge, depending on the phase transition at a given frequency. This may be why a low frequency was specified, so the area of frequential overlap between the two frequencies is as large as possible.
What I mean, is the time factors involved as an issue, at the transition point for both the square and sine are enlarged, at the lower frequencies,and the phenomena may be easier to resolve, or confuse the mind-brain, at the lower frequency. Simple signal ear-brain phasing issues. We recognise the transient, not the phase of it. Low frequencies create negative and positive rarefraction-compression of the air, regardless of the frequency of the signal, that can be easily recognised, even with the pahse being reversed. Otherwise, signals would be more garbled when they are, when they are wired out of pahse with regard to your speakers and speaker systems.
Some people, like me, due to exposure in the world of design on a very regular basis, have taught ourselves to recognise these issues and resolve (with listening, and completing large numbers of 'single cause analysis' experiments) them to a very high level, simply due to a larger understanding of what I am hearing when I listen to audio signals, in any fashion. Many experiments, many correlations, etc. It puts me one step ahead of the next guy who is designing audio gear.
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"Never forget that only dead fish swim with the stream." -- Malcolm Muggeridge.
"Truth cannot be brought down, rather the individual must make the effort to ascend to it." -- Jiddu Krishnamurti
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Sine and square waves percieved pitch, why?
As a special pun to Pass one could mention the title of one of Borges' books - The Aleph.
