Oscillator 1 and 2 are used. Qscillator 3 and 4 are turned off. I dial in a sound with filter 1. When I select oscillator split and parallel the volume decreases (and also the sound changes a bit). Why? Oscillator 1 and 2 should go 100% through filter 1 with this setting, right? So it should sound exactly the same.
(Of course you may ask why I use Osc split when I only use Osc 1 and 2, but this is only for trouble shooting.)