Lift gate on 97 s-10 blazer rattle
 

I have a 4x4 blazer with two Rockford Fosgate p2 12 inch subs in it. The subs rear fire towards lift gate but the rattle they cause is absurd. Wondering I anyone has had the same problem and if they have a solution. The whole gate rattles it's not just components inside. Putting weight on the door helps significantly.

Cars are not meant to handle sound waves that aftermarket subwoofers put out. Companies make some type of insulation that you can put around the factory insulation to help tighten everything up and reduce the rattle effect of the subs. But, if your jammin with the radio turned up, the bass will always make it rattle. You could possibly turn the speakers in another direction...that might help a little but your still going to have a rattle.

There should be some way to help it. Sound deadening won't help much at all I need to hold the door tighter in its spot

I would have to disagree with the last statement. Rattles are nothing more than two objects impacting each other. Typically in a vehicle it's the plastic covers/door cards/door panels/etc. that are impacting the sheet metal or another panel and causing the noise.

There are three different products typically used for sound deadening in a vehicle. The first is CLD (constrained layer dampener) which typically comes in foil backed tiles and is applied directly to the sheet metal. Most of us have heard of and know it as Dynamat but it is sold by many other brands. It's primary function is to stop unwanted resonances in the sheet metal. The old school way of doing this was covering every square inch and many times even in layers to try to block noise from outside the vehicle which is proven the wrong way to use the product. All that is needed is 25% coverage in a single layer as any more than that begins to fall into the law of diminishing returns. It is also one of the most variable products you can buy coming on many thicknesses and materials. The thickness isn't as important as the material it's made from. Older and cheaper products used an asphalt based dampener which releases some bad fumes and don't stick well, especially in the heat. Real Butyl Rubber based products are the superior choice and will usually last much much longer than the asphalt based ones. Prices of this product are generally inbetween that of the CCF and MLV discussed below.

The next product that is used is called CCF (closed cell foam) and is typically made from a 1/8" thick fire retardant, water resistant polymer foam. It decouples the surfaces that are moving and impacting each other causing the rattling. Or in other words it pads the panels so that they can't rattle. This product is generally a fairly consistent one between all the manufacturers and the only real difference is in its resistance to permanent compression. The cheaper products won't resist as much to compression and over time their effectiveness is reduced. An easy answer is to add another layer to the point that becomes a problem. The cheaper ones may also absorb a small amount of water but they won't sponge it up and usually dry on their own easily not causing any kind of disaster. This product is used in a 100% coverage application and this is the cheapest product of the three.

The last is MLV (mass loaded vinyl) and it is actually a sound barrier, blocking sound from migrating into/out of an area. Again the majority of the products on the market all do the same job and do it fairly well. Specifications to look at are the weight per square foot which tells you how much mass it has. The more mass the better it is as a barrier but typically that means it's heavier and thicker which can make it difficult to install, tuck and hide behind the panels in a vehicle. This product is also used in a 100% coverage application and is the most expensive product of the three due to the fact it's installed with 100% coverage and is quite heavy.

While utilizing all three products can yield results you could never imagine inside any vehicle it can and does get expensive to do a full sound deadening treatment. If rattles are the worst of your worries doing a 25% coverage of CLD and some CCF (multiple layers are doable) to eliminate the rattles on your tailgate. There's a problem with doing this though, once you eliminate the rattling in the tailgate you'll hear another place in the truck that is rattling as well. If you treat that one then there will be another because you're hearing the worst one over all the rest. Once you've treated the worst one the next worst of the bunch becomes more audible and easier to locate with your ears. You'll have to decide when you've eliminated enough of the rattles to make you happy with the results.

The brands I recommend most for sound deadening products are SDS (Sound Deadener Showdown), Second Skin, and RaamAudio. While I do feel that SDS and Second Skin have the superior products RaamAudio's products do very well and their prices are the lowest between the three. You can pick up a package deal of their BXT II CLD tiles and IUO CCF together for $160 and it's about enough to fully do two doors.

I have reversed the direction the subs face and that has greatly reduced the volume of the rattle but unfortunately i lost a decent chunk of volume. Thanks you for the info altoncustomtech

i have a 97 with 2 10's and the rear hatch is sound deadened. no rattles at all. i put about 8 square foot of deadener in my rear hatch though. go to amazon and look at gt mat. extremely cheap and good quality sound deadener