gigedit

Gigedit is a graphical instrument editor for sample based virtual instruments, based on the GigaStudio/Gigasampler (.gig) file format.

The .gig file format is one of the major sampler formats supported by LinuxSampler and hence you can use Gigedit both as stand-alone instrument editor, or in conjunction with LinuxSampler for editing such instruments "live" while playing them with the sampler.