Hi/Low Level Line Converter
Use a high level to low level line converter when adding an amplifier to a factory radio to convert the radio's speaker level output to the lower amplifier (RCA) level input.
Since most factory sound systems provide a decent amount of sound quality, a typical 4 speaker setup can not reproduce the low end of the frequency band or deep bass.The most common use of the line converter would be to add it to a factory sound system which in turn will provide for RCA pre outputs to an amplifier for a subwoofer.
Hi/Low Level Line Converter Installation
Hi/Low adapters are devices that installers use to convert a speaker level stereo to RCA levels so it can be hooked to an external car stereo amplifier. You can cut the speaker wires and hook the hi/lo adapter right up or you can tap onto existing speaker wires without cutting them so the speakers still play while the tap gives you a connection to the hi/lo device for adding something like a subwoofer amp to the existing speakers.
Full System With Factory Unit