mainstream media

mainstream media: medios dominantes de comunicación

This rendition caught my eye in the article Traducción y compromiso by Manuel Talens at rebelion.org. He actually renders it as medios dominantes globales but I think they can be medios dominantes in a local context without being globales, though more and more of course they are indeed tied to global conglomerates. El Tiempo, the "leading" newspaper of Colombia, was recently bought by the Planeta group, for example.