In addition, the 2014 BMW 5 Series offers customers a new rear-seat entertainment system with tablet-style displays, a Harman Kardon Surround Sound system and a new version of the ambient light option with a facility which allows the interior lighting to be alternated in tone between orange and white. Classic F10, the 677 option was Hifi Professional which was an unbranded 16 speaker system with basic Dirac processing. (The high-end B&O option has higher-end Dirac processing). LCI F10, the 688 option is branded as Harman Kardon. The US site makes no mention about Dirac processing and BMW NA is unable to answer the question of whether or not Diract processing is included. The international brochure says that the Harman Kardon sound setup has Dirac processing. With the July/August 704 M-Sport Suspension story, I'm going to assume that Dirac processing is limited to the EU models. Harman has good technology also, AuraVox. There are 7x 26mm tweeters. 3 in front, 2 in the rear door, 2 in the rear shelf. These are Harman's Metal Matrix. There are 7x 100mm woofers to go with the tweeters. I haven't taken delivery of my car yet, but I believe these are Alumaprene. Harman doesn't say what this is other than to say that it's better than woven aramide (kevlar). There are 2x 217mm subwoofers under the front seats. These probably go down to 60Hz only. The amp is a Class D amp which is rated at 600W but I don't know what the breakdown is. Since it's class D and they claim a lower wattage for the lower-end BMW's, it's probably a legitimate rating.