a >* b
a >=* b
a <* b
a <=* b
a ==* b

Greater than, written '>*'.  The star extensions are because the
result of the operatros is not of type Bool, as is required by the
signature for the class Ord.

The resulting signal is 1.0 if a > b, otherwise it is 0.0. Similarly
less than is <*, greater than or equal to is >=*, and so on.  

These operators can be useful for triggering purposes, among other
things.

> import Sound.SC3

> let { o = sinOsc KR 1 0
>     ; t = [o >* 0, o >=* 0, o <* 0, o <=* 0, o ==* 0
>           ,(o <* 0.001) * (o >* (-0.001))]
>     ; f = [220, 330, 440, 550, 660, 770]
>     ; p = envPerc 0.01 1
>     ; e = envGen KR (mce t) 0.1 0 1 DoNothing p }
> in audition (out 0 (mix (sinOsc AR (mce f) 0 * e)))