Thanks, Arny -- good tips, great links!

-PW-


Arny Krueger wrote:

"PW" wrote in message




Question: is there a common *range* of percentages
or proportions which seem to represent the smallest
perceptible difference between two stimuli -- also
known as the Just Noticeable Difference -- common to
numerous senses or conditions?



Yes.



So far I've found, in researching this, that a range does
seem to show up -- around 4.8% difference for audio
intensity (i.e., 1dB), around 7.9% for brightness differences
between two lighting levels, around 5% for common
commodity goods prices.



4.8% is about half a dB in terms of intensity. That would be pretty close to
the JND for intensity. Half that isn't generally noticeable for *anybody*.

There's pretty a well known JND related to pitch and frequency modulation.
Check google.

JNDs for things life phase shift and nonlinear distortion are way more
complex.

http://www.pcavtech.com/soundcards/t.../2nd_Thrsh.gif

http://www.pcavtech.com/soundcards/t...m/DifTonTh.gif