[SentraStyleEMW]

More info please

We really need more information before we can direct you to a solution. What type of speakers are they? Do you have an amp running them? What other components do you have in your stereo setup?

 

[SentraStyleEMW]

I have a Pioneer DEH1100 HU putting out 4x40 watts to 4 stock sized Kenwood speakers. They are the ones with the blue cones.

Anyways, sometimes I can play a certain song pretty damn loud with the bass up with no problem, but other times with the same song it will make the popping noise at normal volume levels. I know the speakers are NOT blown cause I've taken the covers off and looked. Oh yeah the sound only comes from the rear speakers, and I have the fade set in the middle.

I would venture to say that you are simply trying to overdrive your speakers. That radio puts out maybe 15 watts rms at most to the speakers. And you cannot tell if a speaker is blown simply by looking at it. Unless it's severely blown...I mean like the voice coil shot up through the cone (which rarely happens). Try adjusting the bass and midbass frequencies as mentioned above to tone it down a bit and you should be fine. If that doesn't work...it is possible that you simply have a bad unit. Which very well could be seeing as you have the same speakers front and rear and only the rear speakers are popping.