You can assign your outputs as; Left+right (standard/normal) Left+left (dual left) Right+right (dual right) Summed L+R both outputs. The summed output increases the output level as, as the name suggests, the L+R are “summed” and delivered as the same mono signal to both outputs. Works for some users. I cant recall from memory but it may be possible that the “main” out and “aux” out can be configured independently. (Dont quote me- need to check the settings to confirm)