Decent Sampler is a great free Sample playback engine with a ton of user configurable synth parameters and effects. We use it on our own Decent Sampler Instruments (available on our Patreon and YouTube memberships)
One of the things that you often want to be able to do is have controls behave more like actual synth parameters. For example, a straight line linear response is fine and dandy, but often you want more detail at the lower and upper values, so you would want something more exponential or custom. Figuring out how and what those values should be is a bit mathematical to be honest.
But don't worry, Sonicstate Patreon member and musician Cephid has created an editor that will spit out custom look up values for programming your own Decent Sampler instruments - you can find it here (as well as a link to his music)
https://sample-tools.moraymacdonald.com/#/translation-table
Find our more about Dave Hillowitz's excellent Decent Sampler here;
https://www.decentsamples.com/product/decent-sampler-plugin/
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