@Mighty23 To avoid pops/clicks at the loop points you need crossfade, which means you need some space before and after the loop point.
The property constants are part of the Sampler class, not a specific sampler.
Try something like:
x.set(Sampler.LoopStart, Sampler.SampleStart); x.set(Sampler.LoopEnd, Sampler.SampleEnd);