I just purchased a Mackie ProFx8v2 for my live sound setup, but someone was telling me that it could be used as a audio interface in recording. My question is, is it compatible with Sonar x3 and if so, does anyone know how to set it up? I couldn't find any good tutorials or instructions on how to set it up on a PC.
 
Thanks!

Read the Mackie manual pages 7 and 8. This covers connecting the device to your PC. The the device and SONAR version on this page for SONAR setup instructions.