Yeah, that probably wasn't the best way to describe the problem. The reason for the zipper noise is that the changes in level are handled by the control rate thread. For smooth level changes we'd have to add smooth ramping between levels on the DSP thread. When we first added this feature, we were adverse to implement it in this second way, because it was going to be a deeper change that would require more work and might push a few algorithms over the resource limit. So, we implemented this in the first way, reasoning that even if it wasn't ideal to do it in the first way there were still a fair number of users who would find the feature helpful and make use of it.