I go 4 fingers down from the collar on the front, and just under the front collar impression on the backside of the shirt. everyones fingers are different so I measured mine and the 4 fingers measure 3.5. I also use my left hand to guage where to put left chest logos.
Grey noise then, has a sound frequency that, if translated to a light frequency, would roughly be the color grey. Grey noise is a random sound that is distinguishable from other types of sound because it sounds the same, to the human ear, at all frequencies.
Black noise is also called silent noise. 1  Silence. 2  Noise with a 1/fÎ² spectrum, where Î² > 2. 3  Noise that has a frequency spectrum of predominantly zero power level over all frequencies except for a few narrow bands or spikes. 4  Noise with a spectrum corresponding to the blackbody radiation (thermal noise).