References : Posted by neolit123 at gmail dot com
Here is a short tutorial about vintage-styled VU meters:
from : User[AT]host[DOT]com
comment : This tutorial has almost no DSP, mostly graphics. Also, the author doesn't seem to realize that abs(x) is not necessary when using sqr(x) because the square of any number is always positive, even if x is negative. I don't really trust a tutorial that is this sloppy.