Unfortunately there is nearly no volume control in Bosca Ceoil, let alone a mixer of any sort. You cannot change any aspect of any instrument's performance outside of the built in lowpass filter, and that effect is applied to all patterns using a specific instrument. It seems that I can't use it for any finished work more complex than chiptune work since any chords or use of instruments with attack or release settings of any kind result in a muddy sound. Bosca's a nice sketching tool but I don't think I can make the actual sound quality any better.