Fans are begging Bradley Cooper to raise his pitch. “Maestro” viewers slammed the actor-director’s performance in the musical biopic on social media, complaining that they couldn’t understand the film’s dialogue to Cooper’s “incessant mumbling. “The mumbling maestro,” one fan wrote on X (formerly Twitter). “So dull and so hard to hear the convos when he and his wife are talking over each other and his deep mumble Ugh. Turned off after an hour.” “Just watched ‘Maestro’ on Netflix. Mixed feelings but wish the diction had been more clear – much mumbling,” a second person wrote. “Trouble is cast and director...