A vehicular audio system receives audio inputs from audio sources and a radio receiver. The LED backlight unit includes a chassis, insulating resin layer, and one or more light source modules. The cooling arrangement is characterized in that the averaged diameter of the solid particles fed the said solid particles ingress means is essentially less than 6 mm. Furthermore, the recording time at a data position may be adjusted to increase the energy directed to the data position by increasing the amount of time the recording beam is impinged on the data position.