2000 renault megane stereo

i have got a 2000 renault megane. the stock system is a cd player (factory fitted) with 2 front tweeters, 2 side door speakers and 2 rear speakers (speakers that are fitted in the trunk). i took out the 2 side door speakers and replaced them with some jbl speakers that fit perfectly. no problem there. but when i run my alpine speakers (SPR - 176A) off the rear speakers it creates a lot of unwanted sound. it is like a shaking sound but is coming from the speaker and not from the car. how do i get rid of it? and also how do i get the best from my speakers without using an amp or a new HU?

SPR - 176A speakers are component speakers they are 2 way speakers a woofer and a 1 inch silk tweeter. are you hooking these speakers up with out the crossovers that came with them? that would do it. if you did hook them up check to see if there grounded or can be grounded.yup