Dolby Noise Reduction in Automotive Applications

In the past decade, the high frequency response of automotive tape playback equipment has been extended, the efficiency of loudspeakers has increased and the cost of high power amplifiers has been reduced. Consequently, tape noise can be a significant problem when listening in the car. This paper discusses the design philosophy of the Dolby B-type and C-type noise reduction systems that are now widely used throughout the in-car entertainment industry to overcome the tape noise problem. Information relating to basic tape parameters, to other approaches to noise reduction and to noise reduction system defects is also included.