Scale economies, well established car maker supply relationships and new product ranges are enabling these four leading system suppliers to meet the ever increasing competition in the automotive audio. Together, Blaupunkt and Siemens VDO represent 55% of audio head units shipped into European vehicle production in 2006, while Delphi and Visteon represent a total of 66% of the audio head units shipped in North America. Alpine, Harman International and Bose, however, are mounting strong and well targeted competition in the premium audio sectors of the market, Strategy Analytics says.