0 to 255
The two parameters Shape and Spread work together to control the contour of the initial envelope of the reverberation sound. Shape controls the actual amplitude contour of the reverberation envelope.
Many small and large spaces have an uneven build-up of initial reverberation, and it is this behaviour that Shape and Spread control.
At low settings, the reverberation builds up extremely quickly and then starts to decay immediately.
As Shape is increased, the reverberation builds up more slowly.
Although the Shape and Spread parameters have been around since the early Hall algorithm, the settings for Random Hall and Ambience do not match. We suggest that if you switch from a Hall to a Random Hall while designing a sound, that you adjust Shape and Spread accordingly.