What data values to map the parameter within.
Mapping within "series" will make the lowest value point
in the series map to the min audio parameter value, and the
highest value will map to the max audio parameter.
Mapping within "chart" will make the lowest value point in
the whole chart map to the min audio parameter value, and
the highest value in the whole chart will map to the max
audio parameter.
You can also map within the X or Y axis of each series.