15m of Speaker Cable OK?

Hey folks, First post here - I'm loving searching through the threads so far! I'm an instrumentalist / midi composer and a recent house move has meant that I can finally have a bigger, quieter studio with a machine room. The studio is currently being built in the garage and my machine room is the old study in the house (large window- good ventilation!). My cable run is 15m minimum as I have to go up into the study ceiling, over the kitchen in the loft and down into the garage. I've managed to find good 15m VGA's, and optical cables, firewire extenders and USB over LAN - but am a bit stuck when it comes to my amp / speakers. I have an ol' O2R in the machine room that sums the lightpipe from my Mac and 2xPCs, and my amp is quiet enough to be in the room with me.... So do I run 15m instrument cables from the O2R out's and have my amp and shorter speaker cables in the control room - or have the amp in the machine room and run 15m speaker cables? I guess the question really is which type of cable suffers the most over that distance? Also, could anyone vouch for a good place to buy the cables? Many thanks - any other advice on machine rooms with this set-up would be gratefully received!!! Tony.

If your amp is not noisy, put it in your control room. If it is the opposite, a pair of powered monitors should be the easiest way

Thanks Serge, So I'm guessing you're of the opinion that it's better to run long instrument cables to the amp rather than long speaker cable? T

I would not use high impedance/unbalanced cables. It would be preferable to use low impedance balanced cables (XLR or TRS connectors)if your monitors have them. Unless you have gauge 10 for speaker cables (compensation for a long running cables) in a situation you have unamplified monitors.