Well, I'll assume that you've at least connected the stereo headphone out of your iPad to the stereo input of your SL device.... So, go into the Setup screen on Scratch Live, and check out the scope views. Make sure that Tonetable is playing. Do you see a circle in the scope view? If not, does adjusting the volume of your iPad up or down allow the scopes to become circles? If not, then is there anything in the scope circles while adjusting the volume?