The answer to this question is yes. However, too often people don't notice it because this type of bias, liberal bias, is the standard, and people confuse that with neutrality and objectivity.
i am pretty sure if you only read/hear about a topic in the WSJ/the WAPO ....OR...only on Fox/BB you are going to be pretty knowledgeable anyway...but.....the number of used angles in the WSJ/WAPO are obviously more numerous and would give you an easy advantage.
even if, as a constructionist i am pretty liberal in that area, even the most neutral and well-meaning person coming from a specific social background is going to report on a topic more from a liberal angle than a conservative angle....you would still learm more from him than from paid pundits who are paid to be pundits.