Ci1 connecting two instruments *confusion*


I am not sure if it is even possible, but by all the limited information I have obtained it should work.

For example, I am trying to connect both a Korg ESX (sampler/drummachine) and a Korg Microkorg synth, the HI/Z port ( 1/L) recognizes the instrument I connect with it, but the when I connect to the 2/R it gives out no sound - on the interface it shows that the channel is peaking if I put gain on it (in recording devices too, it shows the level rising according to pressing the keys), but no sound comes. I somehow heard the both instruments working, but that was distorted and for 0.5 seconds. I think I’ve tried all the various button variations, but still… my nerves are being stimulated in a unhealthy way.

Any solutions? or am I doing something wrong.

Thank you!