Alternative to Dynamat?

that's the carpet under pad.

yeah that's some pretty dense stuff. you could use spray adhesive to help keep it in place I guess

!

Yikes this thread is so full of bad information and terrible advice.  I'll spare the offenders my usual quotations.

Anyway - roofing supplies are a poor substitute for any particular butyl rubber based, aluminum skinned deadners.  I can't stress this enough.

Please remember that few people have experience with more than one deadner and everyone that does thier car with roofing supplies always gets on forums and touts thier genius for the next year - having no idea what a proper Dynamat (extreme) or Copymat installation will really do.  These asphalt based roofing supplies do nothing more than add minimal mass - which does deaden resonance a bit - but nothing on the order of what viscoelastic butyl rubber based-aluminum skinned products like Dynamat or B-Quiet or Damplifier do - these products absorb vibration by virtue of thier molecular makeup - not just by the mass they add to the car panel.

Asphalt-based roofing supplies not only have a particularly strong-odor, which some people report NEVER goes away - but they fail at temperatures that can easily be exceeded by a car parked in sun on a summer day.  Most anecodotal evidence here (from people that stick with forum life and aren't embarassed to be honest about the results of thier peel & seal attempt) point to complete adhesion failure during the second or third summer after installation - after which you can look forward to scraping gooey ashphalt from parts of your car that your hands don't really reach.

Please remember that these products are not "sonic shields" in the sense that people seem to think - I rarely see deadner installed correctly - the purpose of deadner is to remove vibration from metal.  The benefits here are when it is applied across large, flat panels that resonate as sound waves travel through them - car doors, trunk lids, quarter panels.

Also - this discussion of carpet padding - products like these DO absorb airborne soundwaves, but this is a goal for luxury vehicles that want a quiet ride.  For someone installing a stereo, propagation of airborne soundwaves is the GOAL - propagation of soundwaves thru sheet metal and the car body however, is what causes resonance and the majority of rattles - again - the idea here is to deaden the car itself - so stuffing car panels with padding will quiet the ride a bit - and by virtue of that create the impression of increased SQ.  However, obviously the easier and more elegant way to do this is to deaden the panels properly with a butyl based product.

i offer an extreme solution to noise that wont go away it's not pretty or easy but it has worked for myself in the past.  you can use liquid nails* on the  inside of the bodie panel(outside lines), then take polly fill (pillow stuffing) and cram a good amount in the exsisting space then take good old dynomat* and place that over the inside structure where the actual interior panels attach to.  another quick tip for the trunk is to tighten the trunk latch(move down/up) a millimeter or two, it might take more force to close the trunk but it will be much tighter as well.  after your done doing this the car bodie should be a solid as fiber glass.  down side is your car will be heavier and any type of bodie work will be next to impossible.

I have no idea what you are saying here.  Could you rewrite/re-explain this?  Maybe with a picture? 

this computer dosent have any type of drawing softwhre and i cant find any pictures.  i agree with your post that dynomat is the way to go.  the smells associated with the roofing/construction material are awful.  i havent done this since the days before spray deadner so i used liquidnails(or something like it). today,i would actually use spray deadner to get into the tight areas behind the oem speaker mounts. i hope this makes it clearer for you as far my meaning.

Huh?

http://www.woofersetc.com/index.cfm?fuseaction=product.display&Product_ID=1344

Street price on that stuff is comparable with any competing product.

Damplifier Pro is a very nice looking product - I can't stand all the half cut Dynamat logos that look back at you when you open my trunk lid - I'm thinking of doing it again with Damplifier Pro.  That clean aluminum look of all the Copymats is really slick. 

Well said, sedate, and a welcome dose of reality for this un-12volt-like thread.