Currently the max audio sources that can play at once time is 3... after 3, additional sources will refuse to play...
I can only assume this was implemented to prevent people from putting 10 of the same audio source to make loud earrape whatever, but for creators this is a severe limitation.
In my case, i am very prideful of dealing with quality audio, and making good use of audio source placement and so on. Using right/left channel splitting for stereo, using mono sources for individual effects and so on. But with only 3 active audio sources, it's basically impossible to do anything really inventive and dynamic with use of audio sources. It doesn't stop people from making loud shit, it just makes it harder to make more legitimate stuff to show people.