subwoofer rattles like hell

Verify the polaity of those speaker cables since the sub is seeing a full range high level speaker signals.

SET UP CALIBRATION

For best results when setting up your system, assume your normal listening position and have another person perform the following adjustments:

1) Start with the Subwoofer Level Control to its zero position. Set the Subwoofer Low Pass Filter Control to 50Hz.
IMPORTENT: Set any loudness, bass/treble, and/or equalization controls on your intregrated amp to their normal or mid-point positions.
2) Play a familiar CD, Record or Video Soundtrack that has substantial bass content.
3) Gradually turn the Subwoofer Level Control clockwise until you achieve a neutral balance between the subwoofer's deep base output and your main/satellite speakers.
4) Slowly turn the Subwoofer LP Filter Control clockwise to reach the best mid base blend with your main/satellite speakers. This will be the point at which the bass retains solid impact and fullness.
If the bass becomes "boomy" or ill defined you have gone to far and should turn the control counter-clockwise to the best balance point. If the sound is too thin (ie. male vocals are not full sounding) then turn control clockwise to the best balance point.

NOTE: The Subwoofer Level Control is design to control the balance between your sub and main/satallite speakers and should not be used as a substitute for the bass or loundness controls on your intergrated amplifier. Adjust the subwoofer's level for smoothest low frequency performance. If more bass is desired, then advance the bass and/or loundness controls on your intergrated amp.

Good luck

Room placement and interaction with reinforcing and null modes will be another story.

Common sense dictates that, if the unit contains 2 identical drivers, and only one rattles, there is a problem with the rattling one. As was mentioned, check the tightness of the screws on both drivers (always a good idea on subs!). You may also wish to carefully open the sub to make sure nothing has come loose that the cone might be hitting. If there is no obvious reason for the problem and you purchased the sub new, it should be repaired (or they may send you a new driver to install yourself) under warranty.
My credentials: I have been an audio manufacturer for over ten years, an electronic technician for over 30 years, and an audiophile even longer. (IMHO, anybody offering advice beyond what components they like or dislike should indicate their technical background).

Alrau1, it is a push pull configuration so i think if the drivers are pushed too hard it might overload just one of them. what you say does make sense though. problem being i bought it used and it seemed to work pretty good until i made all my adjustments and break in time of the other components, so manufacturers warranty is not an option. it, sadly, was a stretch for me to purchase even used (i'm saving for a bigger house) and i fear repairing will be out of the question. i guess i was hoping for a different answer but thanks a ton for everybodies input!

I just look at the owners manual. The sub has BOTH Hi-level inputs AND outputs with the inputs being the BOTTOM row. Verify your connections, just covering all bases.
Otherwise contact the manufacturer. (go to Audiongon's home page and see manufacturer's list link on the right side for contacts and website).
Good Luck.

thanks for your attention, i had done all those things, i am contacting mirage.