This is easy to test:
- Pick Drumkit “Power Kit 1” and listen to how the snare normally sounds
- Add an “AUX FX 1” send to the Program Bus
- Add an effect that requires look-ahead to the AUX FX 1 send, such as the Compressor or a limiter/maximizer
This results in very obvious comb filtering, which doesn’t go away until you remove the effect or switch to the Compressor’s live mode.
This affects all Halion engine instruments that use sends, such as Groove Agent 4 (where using compressors and limiters as sends for parallel processing is most useful).
If this can’t be fixed or made into a setting, there should be at least a warning in the manual about this.