"When I set the audio to my Saffire nothing happens" is too less information for troubleshooting. "...sounds like garbage" as well. From that, nobody can figure out what happens on your system.
Please post a OBS logfile and a description of how the audio is set up at your PC. A possible issue for sound distortion may be if the sample rate of the Windows audio device and the sample rate of OBS doesn't match, of if the sample rate of the Windows audio device is different to the sample rate of some external input.