Freesound Forums

I want to mix by adding sounds over and over to making nature sound or sleeping sound with a picture or video and I want to use it for commercial use in youtube. Can i use CC BY 3.0 licenced sounds ? If i can use What should I pay attention to?

You can use CCBY licensed sounds for this. You must however attribute/credit the authors of the sounds included in the videos. this can be done either in the Youtube video description or even better, included in the video credits.

Please check the Creative Commons Best Practises for Attribution guide on their website.

If you can't/don't want to give credits then I suggest you use only CC0 licensed sounds.