Space Designer IR Start controls in Final Cut Pro
The Space Designer effect’s IR Start parameter enables you to shift the playback start point of the impulse response, which effectively cuts off the beginning of the impulse response.
This can be useful for eliminating level peaks at the beginning of the impulse response sample. Its use also affords a number of creative options, particularly when combined with the Reverse function. See Space Designer button bar in Final Cut Pro.
Note: The IR Start parameter is not available or required in Synthesized IR mode because, by design, the Length parameter provides identical functionality.