length of interconnects for passive preamp

Many thanks to all; I'll go with 1/2 meter. I did not realize the quality of IC mattered more with a passive preamp. The IC that was recommended was made with mogami 2549 cable and neutrik rean connectors.  I'm very much looking forward to seeing what improvement there is going from  3 meter to .5 meter. 

My passive sucked the life out of my system when I was using very inefficient speakers and monoblocks, which required  3 meter ICs. I recently switched to very sensitive speakers (horns) and a stereo amp  and the passive sounds great even with the same ICs. the reason for my q was I want to purchase shorter interconnects to get it to sound even better (and the fact that I do not require this length). I will purchase 1 meter or .5 meter ICs - question is what brand - to be honest I do not quite understand the specifics of some of the previous posts but want to express my thanks and appreciation for your contributions. 

The speakers cables were made for me by a local tech and I do not have the specs. I will report back after I try the shorter ICs. Regarding my prior 3 meter ICs I I started with cardas microtwin, which seemed to "round out" the sound and were a little muddy,  then I changed to a more expensive cardas - I can't recall the specific model - which was a step up - and then I had 3 meter ICs made by Stephen Sank, who is a tech/modifier of equipment based in Arizona -   they are unshielded and were inexpensive - but were MUCH better than the other 2 - so I may purchase shorter ICs from him or send the 3 meter back and have him make 2 pair of shorter ICs.