good day mga gurus! i have a problem regarding my sound system. Everytime i turn on my stereo, there is a loud "THUMP" coming from my speakers especially sa subs!lalo na when i turn it off!minsan nga nagulat pa mom ng gf ko when i turned it off sa lakas!what could be the problem?straight targa ang set up ko!12" ang subs and v12 amp!thank you mga sirs!