Obs audio distortion

I’ve been trying to get obs configured on my macbook for the last few weeks. I’ve set up an aggregate device in midi setup with Ishowu audio output and my soundcard. I can get the audio to actually show up in my headphones and into obs finally, but I’m getting crackling audio distortion that I can’t figure out how to fix. Everything works fine until I fire up Obs. Wondering if anyone has any idea what is causing it as I feel like I’ve tried everything.

I’m using an audibox usb sound card (it sucks…)
macbook pro retina 15 inch(mid 2014)
os x 10.10.5
obs 20.1