my speaker got engine noise when i accelerate,wat the problem ? how to fix it ?

engine noise? or u mean like whistling sound ?

ya whistling sound,it connect through my speaker..do u know how to fix it ?

im nt so sure...did u just install any new accessories? says pre-amp or some sort lke tht... anyway I think there are device that u can install to cut tht annoying sound out... juz bring to workshop and they wil knw... a small cube thng...orelse...some voltage stabilizer sellin on market can help also....

u need additional grounding...use thick copper cables....welding cables are the best....dont bother with those HKS imitation type....u can also use the thick power amp cables they use for sound system.....goodluck

The above statement is hiding the issue.
Much better way, is to locate the source of the problem and rectify it. Dat u will need installer help as they are too many variables to consider