Inside the headphones' booming popularity, especially in Eastern Europe. Our OQ On the Street column goes over the ears. Marshall is best known as the maker of amplifiers for many of the world's most legendary acts. The company began breaking into consumer sound with headphones and speakers a number of years ago, with their most successful pair of cans - the Major series - mirroring the shape of those famous amps. They never quite took off in large developed markets, though,