Calculates the rate for an envelop parameter for a given amount of time.
time: time in seconds. Can be a fraction of a second.
freq: the frequency which the envelope generator is being updated at (e.g. sampling frequency)
high: the higher value of the envelope stage.
low: the lower value of the envelope stage.
Note: The high and low values must be kept in order even in case of an ascending stage.
Calculates the rate for an envelop parameter for a given amount of time.
time: time in seconds. Can be a fraction of a second. freq: the frequency which the envelope generator is being updated at (e.g. sampling frequency) high: the higher value of the envelope stage. low: the lower value of the envelope stage.
Note: The high and low values must be kept in order even in case of an ascending stage.