are there any cheaper alternatives to Dynamat?

I've heard that spray-on truck bed liner works well, as does rubberized undercoating (but it doesn't dry as well)

 

edead from www.edesignaudio.com

 

I've heard good things about Rammat.

 

www.b-quiet.com
I swear by this stuff.

 

ok, forget about spray on truck liner. there is a spray on urethane liner that they put on truck beds to abosorb the impact of tools, ladders, or anything that could scratch or dent a truck bed. these applications offer a non-skid resistant coating for prices anywhere from $250 $1000 bucks. quite frankly i forget, and i'm pretty sure you 'could' theoretically use it to deaden in your car, but i'm pretty sure you'd be the first idiot to try it. so more power to you. just use b-quiet (http://www.b-quiet.com) as dave said, or you can use RAAMat (on sale at http://www.cureline.net/lex/raamsale.htm or just regular price at http://www.raamaudio.com/products.htm). i post RAAMat links only because this is what i'm hoping to try. to tell you the truth, there is no difference in the deadening capacity of some dynamat that maybe 45 mils thick and another brand that is 45 mils thick, it's the same ****, just a matter of what is cheaper really.
peace

 

when i rebuilt my trunk, there were some odd spaces, especially on the trunk lid itself. to fill those and eliminate rattle, i used expanding foam from lowes. it works great, you just spray and it expands and hardens.

i wouldnt use it to coat everything, just to fill odd spaces and gaps between metal. it runs for like 5 bucks a can

 

best thing I found was the rubberized undercoating. Put about 4 coats, and your drunk will pump the bass through your car, without all the rattle.