I have just plugged in my speakers into my new iMac, that were formerly attached to my now replaced PC. They are Creative I-Trigue L3800, which is a 2.1 system. The speakers work fine, but the sub is not producing anything, but is okay when plugged into my PC. I've just tried the speakers on my MacAir and have the same result as for my iMac. Could it be that Macs are not able to drive the speakers?