Reply to Possible soundcard problem?

Hello, so I was just broadcasting live on mixlr and someone informed me that there was a loud buzzing on the audio, I checked it out and sure enough there was.

But I can't work out what was causing it, I checked all the connections but nothing was loose. I stopped the broadcast, opened up audacity and recorded the audio that way and it was crystal clear.

Restarted my laptop, changed the usb port, checked all the settings, but every time I broadcast the buzzing is there. I was live last week without anu problems too, I've checked the saved recording on the mixlr site.

I'm using 2 CDJ 2000s with a DJM 800, going via the record out into the line in of a Numark DJ IO USB soundcard.

Anyone got any suggestions?

Thanks.