okay i realised that i need mixer for my synths.. pluggin in the cables and out from my soundcard interphace is anoyying. can you tell me how do i set up a mixer with my soundcard and synth racks?

also do i really need a mixer for this or i could do it the anoyying way?

 

you could get a line mixer cheaper than a console; and it would take up much less space, or even get a rack unit. You could get an audio interface with a good number of analog ins. A 1/4" patchbay would deal with your unplugging complaint, but it would not increase the amount of devices/synths you could send in to your interface simultaneously. These are some of the more common ways people setup their synths.