The curve display update speed is controlled by the ballistics settings.
The release time determines how fast the main curve falls back to zero. Default is 300ms.
The controls the release time of the optional Max curve, which serves to display the medium-to-long term tendency of the magnitude spectrum. Longer times mean curve maxima/peaks will be seen for a longer period.
Default is 50 seconds.
The attack time is zero so the curve displays reacts instantaneously to a rising amplitude.