Outdoors, where you can put some distance between yourself and them?

Sure, if it's one person. Where I used to live, the nearest park would have multiple groups engaged in loudness wars, each upping their volume in response to the others, so nobody could enjoy the park. Public spaces shouldn't be held hostage by assholes who don't understand how to behave in public, to the detriment of everyone else.

As far as what to do, it would be nice if the existing rules would be enforced that prohibit this behavior, but people cry racism for being told off for bringing a massive speaker to blast merengue and dembow in the park and somehow find support, rather than people asking why they're blasting any type of music in the park to begin with.