When you want to switch stereo modes using the remote all you have to do is press the "Stereo" button repeatedly to cycle through the various formats. Make sure the input you are using is configured for the format you want to hear and then all you have to do is swap to it. None of the Dolby or DTS modes will work well for a two channel system as they are designed to take two channel and make it into 5-6-7 channel. I would expect to lose some information to the mains if that were the case because some of the sound is being routed to non-existent speakers. Make sure the Macbook is configured to output the 2.1 signal. Not being familiar with Apple products I can't give specifics but it must have a sound output program you can adjust. It sounds like the Macbook isn't putting out the LFE channel and if the crossover is set above 60 hz you would lose a lot of the bass signal.