A wild guess - you have an unbalanced patchbay.

What happens if you go directly from the synth to the mixer line input with balanced and unbalanced cables, bypassing the patchbay?

When I plug into the line on the mixer its the same problem, less volume when I use the balanced patch cable. This is coming out of a motif rack. My MS2000 doesent have this problem, it goes through the patch bay and is balanced and I dont have to touch the trim knob. What gives?

To make a balanced cable work, the gear at both ends has to be designed to work with a balanced connection. That doesn't necessarily mean it have to be balanced itself, but that the designer has thought about what happens when using both balanced and unbalanced connections.

A sufficient explanation for your effect is that the output socket on the Motif (you don't say whether it's TRS jack or XLR) has only the hot pin and ground connected, leaving the cold pin floating. You could re-wire the plug or buy an adaptor that will ground the cold pin, but is there actually a great need to use a balanced connection here if there are no problems with the unbalanced one?

the motif has a 1/4" out, 2 of them infact, its stereo, Left socket and Right Socket. Left being the mono socket. im only using it for a lead so there isnt a real noticable differance in mono or stereo. so your saying that it doesent matter if i use a balanced or unbalanced except that i lose volume?

No, in your case it clearly does matter. I'm suggesting you stick with the unbalanced cable since that seems to work, unless you have an overriding reason to use balanced, in which case you will have to crack the problem of gain loss. This may involve opening up the synth and inspecting the output jacks. Without that, it could be that the only way of making a balanced cable work is to unbalance it.