truck sounds like soda cans in the back

Ok, a couple questions. My truck sounds like I have a bunch of cans in the back rattling around. Not only that but I think im losing a lot of SPL. 

As far as performance goes does dynamat extreme perform better than brown bread? Now for those of you reading this and responding to it, take price out of your mind and give me your opinion on sound dampening.

Last thing. Those pop cans I was talking about, well, is sound dampening going to reduce this? I used dynamat once a while ago and it helped my stereo sound a lot better, as far as rattles go I didnt have many in the first place so I didnt even notice.

Thanks

Brown bread is definately better than dynamat.   Its hard to say if it will stop your rattles.  If its panels, then it will make a good difference, ,  but if its things behind the panels, then that will take a lot of work to brace them.

Just turn on your stereo and sit in the back trying to listen for every rattle, , grab it with your hand, , if it stops buzzing then thats your rattle, , and move on to the next one.

just take the cans out of the trunk! DUH!. haha, just kidding. I've yet to use any name brand sound dampening products, so I cant answer you on that, but they will definitely increase your SPL. rattling is a sound waves enemy. The cleaner it can move, the better it will sound.

I think this might be helpful to those who also have the same question as I do. http://www.b-quiet.com/compare.html  Looks to me that they are comparable. As you can see the sound dampening material absorbs best at roughly 68 degrees F whic would be a decent tempature inside a vehicle. On top of that dynamat barely performs better at that tem and at 32 F as noted by the specs. I dont know about some of you but if Im in my car and its freezing im not listening to my stereo that loud. I would have to say overall it looks to me like BB is the winner. I will be ordering some of that soon.

Anyone else with any comments?

BB and Dynomat perfrom pretty much the same, IMO.  Buy based on price.  Now as far as trying to kill the rattles in your truck with 4X12's in your custom enclosure, you may be, as they say, SOL.  You have way too much SPL capability in a very small space, and anything short of removing EVERYTHING from the cab, sanding it to bare metal and welding in new bracing may just not be enough.

The first and easiest place to start, though, is to make sure none of your soda can sounds are coming from the enclosure itself.  Take it out of the vehicle and turn it on sitting by itself next to the truck, and see if it rattles on its own.  Start by fixing those first.  Then go for the easy fixes like securing your trim with RTV, etc.