Patent ID: 7697698

Claim:
A safety system for a host vehicle whose driver can be protected from audible noise, said safety system comprising: (a) one or more directionally discriminating microphones on said host vehicle that discriminate against audible noise made by said host vehicle, (b) one or more loudspeakers positioned so that said driver can clearly hear sounds produced by said loudspeakers (c) signal processing means whose functions include amplifying signals from said microphones and feeding amplified signals from said microphones to said loudspeakers, said microphones sensing sounds made by objects in said host vehicles environment, and said safety system is configured so that said driver hears reproductions of the sounds made by nearby vehicles that are close enough to said host vehicle that said driver should be aware of said nearby vehicles for purposes of safe driving, said driver can approximately locate by ear the position of said nearby vehicles that he or she apparently hears, and said driver is generally unaware of sounds from said safety system that originate from said host vehicle, whereby said driver is made aware of the presence of said nearby vehicles behind or beside said host vehicle, and said directionally discriminating microphones in combination with said signal processing means greatly improve the quality of sounds provided to said driver so that said driver is not annoyed by additional noise from said host vehicle, said signal processing achieving said improvement in signal quality in part by continuously, or nearly continuously, changing the gain for at least one part of the audio spectrum based on signal intensity in another part of the audio spectrum, thus exploiting the directional property of said microphones and the frequency characteristics of the sound of vehicle tires rolling on pavement.