World's Ten Most Colorful Flags. Here are ten of the most colorful flags from around the world. While it is fairly common for flags to have just three colors, like the red, white, and blue of the United States or the black, red, and gold of Germany, some flags are much more colorful than that. What makes a flag colorful tends to be a subjective decision, however.
The wind noise spectrum is dominated by the lower. frequencies (< 500 Hz), although at 27 mph when. saturation is present, the wind noise level can be greater. than 60 dB SPL at 8 kHz. It is clear that wind noise is at. high levels at commonly encountered wind speeds and. needs to be suppressed.
The frequency of most dog whistles is within the range of 23 to 54 kHz, so they are above the range of human hearing, although some are adjustable down into the audible range. To human ears, a dog whistle makes only a quiet hissing sound. The advantage of the dog whistle is that it doesn't produce a loud irritating noise for humans that a normal whistle would produce, so it can be used to train or command animals without disturbing nearby people.