Adding or changing your RSS feed's category
In order to submit your RSS feed to iTunes, you must choose a category that reflects what your podcast is about. This way, listeners that are interested in that subject area can find you easily in iTunes.
Go to your Content Settings page, and choose your podcast’s category.
Choosing a subcategory, or second category
It is not currently possible to choose a subcategory, or a second category for your podcast through SoundCloud.