The high-pitched whine that goes up and down in pitch with engine RPMs comes from the alternator and is entering the power wire on your stereo. Or, it is being picked up in an “upstream” component like a receiver or equalizer and entering the amp through RCA leads: that requires a different type of suppressor. Re-grounding components is the first course of action. If a suppressor becomes necessary, you may have to install more than one or more than one type, depending on the your system’s complexity. Use the process of elimination to determine where to locate suppressors. Tips Writer Bio
