How can I make the amp envelope corresponding to note length

Thought I had this figured out, but ever since switching to mpc, it seems like the amp envelope has little to no bearing on how the notes sound as I play them. If anyone could let me know how to tighten up my amp envelope, I'd greatly appreciate it!

Make sure your sample play pad mode is Note-On, and not One-Shot. With One-Shot, the note length really doesn't mean anything, it's like a drum hit.