Car Stereos: Speaker rattles?, pressure waves, rear speakers

Question
QUESTION: Hey Brian i have an brand new sound system in my car, about 3 months old. My two front speakers are amplified but the two rear are not. One of my rear speakers rattles when i turn my music up. Im not sure if its blown or not. What do you think?

ANSWER: Hi Matt,

It's hard to say without hearing it.  

It's possible that the woofer suspension or surround has been damaged.  That's what most people mean when they talk about a "blown" speaker.  However, that's not the only possible cause of a rattling speaker.

Another possibility is that the speaker is poorly mounted.  Maybe one or more of the mounting screws has worked loose.  In this case, the speaker itself may be bouncing up and down in its mount.

I've also seen the center tweeter pod come loose.  Sometimes the mount holding the center tweeter runs through the magnet to the back plate.  It's secured by a screw through the middle of the back plate.  I've seen the screw come a bit loose, resulting in a rattly center tweeter pod.

Or, it's possible that some interior panel in the vehicle isn't well secured, and is rattling from the vibration.  In this case the rattle isn't coming directly from the speaker, but from something near the speaker.

If you can get to the bottom side of the speaker, you might try bracing it with your hand while it's playing, to see if that affects the rattling.  Similarly, you can try using your hands to dampen nearby panels while it's playing, in case the rattling is coming from the panels.  In the end, though, you might have to remove the speaker from its mount entirely.  If it still rattles when dismounted from the vehicle, then you'll know it's a problem with the speaker itself.

Hope this helps!

Brian

---------- FOLLOW-UP ----------

QUESTION: Thanks for the reply, i also heard that pressure waves from a subwoofer could also damage a speaker. I recently turned my ported 10 inch sub box so its facing this speaker, but this was 2-3 weeks ago. Could it have been the pressure waves? If so it would help prevent this from happening again.

Answer
Matt,

I've seen cases of air flow from a ported or bandpass box causing distortion in rear speakers, in cases where the port output is right next to the speaker; but I haven't seen a case of speaker damage as a result.  I'm doubtful that this was a factor in your system.

Brian