Crash with group xfades and Synthesizer Group

[tomekslesicki]

How to reproduce:

1. create a Synthesizer Group, add two samplers
2. load two sample maps into each of the samplers, the sample map needs to have some rr groups
3. enable group xfades on both samplers
4. play any note

You'll get an instant crash. I also noticed the voice count goes crazy high, which might be a clue as to what's happening.

This is on the newest develop branch, and the master.

@Christoph-Hart - could you please take a look at this?

Thanks!

[Christoph Hart]

@tomekslesicki The problem is that the XFade starts multiple voices for the same note which the SynthesiserGroup does not handle well and there is not an easy fix for this - the synthesizer group is a very specialized use case for adding FM & unisono on a voice level and isn't suited to handle multimic voices or Fade samples very well.