Animated sound waveform Make an animated sound waveform using any programming language your prefer, the squares of the spectrum can be of a single color (no rainbow effect).
The animation must be infinite and not a loop sequence (must be a random animation).  

You can use any kind of external library you prefer.

This is a code-golf so the shortest code will win.

Example of waveform:


(a screenshot of the result is appreciated)

Edit:
I thought was obvious,but the waveform must be horizontal.
APL (61)

{∇n⊣⎕DL.1⊣⎕SM←1 1,⍨⊂' '⍪⊖⍉↑⍴∘'▇'¨,0,⍪n←24⌊0⌈⍵+3-?5/⍨⍴⍵}?24/40


It starts with random-sized bars, and changes the height of each of the bars by a random number between -2 and 2 each frame.

Screenshot: