That is correct. You will have to run one of the outputs of your mixer (master, booth, record [if it has recording output]) into your other soundcard and use a separate program to record (audacity, soundforge, etc.).

Ok now would I be able to plug my sl2 into my sound card and record into ableton live? I use ableton and have yet to use scratch live. I want to run both scratch live and ableton on the same computer and work out of both of them. I read about the bridge but I am just confused on how scratch live and ableton work together. My idea is to use scratch live to run my turntables and then record that into ableton well using ableton to add effects and other sounds, and also to transfer sets from ableton into scratch.