Been using my X3 Live for practice and a back up for live rigs. Today, I connected to it today to practice and it's weird. The Master Volume just effects the guitar signal; the manual says it should do the MP3 In also, but it does not. The headphone out just gives me the left channel. I see nowhere to change anything pertaining to the Phones or MP3 In. Before I connect it up to the laptop, does GearBox have a setting for them? Very frustrating. The MP3 is quiet and distorted and the guitar is over powering. I have set this up earlier and it worked great. The MP3 was a little weak, but both sides worked. I try the headphones direct to the MP3 player and they sound great.