Question about fine resolution in plugins

I sometimes do SFX work which requires very fine envelope work. I’m already a Spectro fan and I’m currently trying out Sculpto. When looping content and editing the parameters in Sculpto, I’ve found that setting certain parameters a certain way can result in repetitions not sounding the same. And for example, I’m processing a 150 ms sample using Spectro in Reaper and every time it plays, the Spectro graphic gets redrawn differently even though it sounds the same. I’m just wondering why these differences occur? What I usually end up doing when there is an audible difference is copying the sample, render the multiple copies and then keep what I want.

This has been going on for years as most audio processing is geared towards music rather than sound design which doesn’t have the same time and predictability constraints. I’m curious to know what the reason is for the variation in the code execution and what the limit of time granularity is for the Schwa plugins in particular and how much of it is limited by the hosts’ capability.


Hi! The visual difference is probably due to interaction between the actual floating-point time location of each sample (which doesn’t change), the exact sample location of the playback start (which does change), and the audio buffer size. When playing back in a loop, the exact sample location of the playback start can vary on every iteration because the loop length will not be an exact multiple of the audio buffer size. Since Spectro measures its drawing from the first sample it sees, if the exact time location of that first sample moves around (even though the actual audio content still plays at the same time location every time), the pixels will be redrawn.