dbrown  length lo hi step
dibrown length lo hi step

Demand rate brownian movement generators.

lo              - minimum value
hi              - maximum value
step            - maximum step for each new value
length          - number of values to create

Dbrown returns numbers in the continuous range between lo and hi,
Dibrown returns integer values.  The arguments can be a number or
any other ugen.

> n <- dbrown 32 0 15 1
> let x = mouseX KR 1 40 Exponential 0.1
>     t = impulse KR x 0
>     f = demand t 0 n * 30 + 340
> audition (out 0 (sinOsc AR f 0 * 0.1))