Attendees listen to music with Polk Audio Inc. UltraFocus 8000... Photo d'actualitéAmérique du Nord,Apple Incorporated,Californie,Casque audio,Continent américain,Dispositif portable,Finance,Horizontal,Industrie électronique,MacWorld Expo,Moscone Center West,Musique,San Francisco - Californie,Technologie,Écouter,États-UnisPhotographer Collection: Bloomberg 2013 BloombergAttendees listen to music with Polk Audio Inc. UltraFocus 8000 headphones at the Macworld/iWorld conference at the Moscone Center West in San Francisco, California, U.S., on Thursday, Jan. 31, 2013. This year's conference, titled 'The Ultimate iFANEvent,' brings together attendees to celebrate Apple Inc. technology and learn more about products and services for Apple users. Photographer: David Paul Morris/Bloomberg via Getty Images