Review on Enhance Audio Quality with Scosche EF014F 10-Amp Noise Filter by Jon Cherian

100% perfect solution to my problem. I found that the high-pitched hum coming from my speakers at low engine speeds was being generated by my alternator and fed to my radio through the antenna wire. If this is your problem (it's easy to check by simply unplugging the radio antenna while the radio is on and seeing if the hissing stops) I'm pretty sure this is what you're looking for. The negative reviews are hard to understand unless it is installed correctly or the noise is NOT fed to the radio through an antenna.